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Commit ea272257 authored by Mauro Carvalho Chehab's avatar Mauro Carvalho Chehab Committed by Jonathan Corbet
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docs: histogram.txt: convert it to ReST file format 

Despite being mentioned at Documentation/trace/ftrace.rst as a
rst file, this file was still a text one, with several issues.

Convert it to ReST and add it to the trace index:
- Mark the document title as such;
- Identify and indent the literal blocks;
- Use the proper markups for table.
Signed-off-by: default avatarMauro Carvalho Chehab <mchehab+samsung@kernel.org>
Acked-by: default avatarSteven Rostedt (VMware) <rostedt@goodmis.org>
Signed-off-by: default avatarJonathan Corbet <corbet@lwn.net>
parent 60a86668
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Documentation/trace/events.rst
View file @ ea272257
......@@ -524,4 +524,4 @@ The following commands are supported:
totals derived from one or more trace event format fields and/or
event counts (hitcount).
See Documentation/trace/histogram.txt for details and examples.
See Documentation/trace/histogram.rst for details and examples.
Documentation/trace/histogram.txt → Documentation/trace/histogram.rst
View file @ ea272257
Event Histograms
================
Event Histograms
================
Documentation written by Tom Zanussi
Documentation written by Tom Zanussi
1. Introduction
===============
......@@ -19,7 +21,7 @@
derived from one or more trace event format fields and/or event
counts (hitcount).
The format of a hist trigger is as follows:
The format of a hist trigger is as follows::
hist:keys=<field1[,field2,...]>[:values=<field1[,field2,...]>]
[:sort=<field1[,field2,...]>][:size=#entries][:pause][:continue]
......@@ -68,6 +70,7 @@
modified by appending any of the following modifiers to the field
name:
=========== ==========================================
.hex display a number as a hex value
.sym display an address as a symbol
.sym-offset display an address as a symbol and offset
......@@ -75,6 +78,7 @@
.execname display a common_pid as a program name
.log2 display log2 value rather than raw number
.usecs display a common_timestamp in microseconds
=========== ==========================================
Note that in general the semantics of a given field aren't
interpreted when applying a modifier to it, but there are some
......@@ -92,15 +96,15 @@
pid-specific comm fields in the event itself.
A typical usage scenario would be the following to enable a hist
trigger, read its current contents, and then turn it off:
trigger, read its current contents, and then turn it off::
# echo 'hist:keys=skbaddr.hex:vals=len' > \
/sys/kernel/debug/tracing/events/net/netif_rx/trigger
# echo 'hist:keys=skbaddr.hex:vals=len' > \
/sys/kernel/debug/tracing/events/net/netif_rx/trigger
# cat /sys/kernel/debug/tracing/events/net/netif_rx/hist
# cat /sys/kernel/debug/tracing/events/net/netif_rx/hist
# echo '!hist:keys=skbaddr.hex:vals=len' > \
/sys/kernel/debug/tracing/events/net/netif_rx/trigger
# echo '!hist:keys=skbaddr.hex:vals=len' > \
/sys/kernel/debug/tracing/events/net/netif_rx/trigger
The trigger file itself can be read to show the details of the
currently attached hist trigger. This information is also displayed
......@@ -140,7 +144,7 @@
can be attached to a given event, allowing that event to kick off
and stop aggregations on a host of other events.
The format is very similar to the enable/disable_event triggers:
The format is very similar to the enable/disable_event triggers::
enable_hist:<system>:<event>[:count]
disable_hist:<system>:<event>[:count]
......@@ -153,16 +157,16 @@
A typical usage scenario for the enable_hist/disable_hist triggers
would be to first set up a paused hist trigger on some event,
followed by an enable_hist/disable_hist pair that turns the hist
aggregation on and off when conditions of interest are hit:
aggregation on and off when conditions of interest are hit::
# echo 'hist:keys=skbaddr.hex:vals=len:pause' > \
/sys/kernel/debug/tracing/events/net/netif_receive_skb/trigger
# echo 'hist:keys=skbaddr.hex:vals=len:pause' > \
/sys/kernel/debug/tracing/events/net/netif_receive_skb/trigger
# echo 'enable_hist:net:netif_receive_skb if filename==/usr/bin/wget' > \
/sys/kernel/debug/tracing/events/sched/sched_process_exec/trigger
# echo 'enable_hist:net:netif_receive_skb if filename==/usr/bin/wget' > \
/sys/kernel/debug/tracing/events/sched/sched_process_exec/trigger
# echo 'disable_hist:net:netif_receive_skb if comm==wget' > \
/sys/kernel/debug/tracing/events/sched/sched_process_exit/trigger
# echo 'disable_hist:net:netif_receive_skb if comm==wget' > \
/sys/kernel/debug/tracing/events/sched/sched_process_exit/trigger
The above sets up an initially paused hist trigger which is unpaused
and starts aggregating events when a given program is executed, and
......@@ -172,8 +176,8 @@
The examples below provide a more concrete illustration of the
concepts and typical usage patterns discussed above.
'special' event fields
------------------------
'special' event fields
------------------------
There are a number of 'special event fields' available for use as
keys or values in a hist trigger. These look like and behave as if
......@@ -182,14 +186,16 @@
event, and can be used anywhere an actual event field could be.
They are:
common_timestamp u64 - timestamp (from ring buffer) associated
with the event, in nanoseconds. May be
modified by .usecs to have timestamps
interpreted as microseconds.
cpu int - the cpu on which the event occurred.
====================== ==== =======================================
common_timestamp u64 timestamp (from ring buffer) associated
with the event, in nanoseconds. May be
modified by .usecs to have timestamps
interpreted as microseconds.
cpu int the cpu on which the event occurred.
====================== ==== =======================================
Extended error information
--------------------------
Extended error information
--------------------------
For some error conditions encountered when invoking a hist trigger
command, extended error information is available via the
......@@ -199,7 +205,7 @@
be available until the next hist trigger command for that event.
If available for a given error condition, the extended error
information and usage takes the following form:
information and usage takes the following form::
# echo xxx > /sys/kernel/debug/tracing/events/sched/sched_wakeup/trigger
echo: write error: Invalid argument
......@@ -213,7 +219,7 @@
The first set of examples creates aggregations using the kmalloc
event. The fields that can be used for the hist trigger are listed
in the kmalloc event's format file:
in the kmalloc event's format file::
# cat /sys/kernel/debug/tracing/events/kmem/kmalloc/format
name: kmalloc
......@@ -232,7 +238,7 @@
We'll start by creating a hist trigger that generates a simple table
that lists the total number of bytes requested for each function in
the kernel that made one or more calls to kmalloc:
the kernel that made one or more calls to kmalloc::
# echo 'hist:key=call_site:val=bytes_req' > \
/sys/kernel/debug/tracing/events/kmem/kmalloc/trigger
......@@ -247,7 +253,7 @@
We'll let it run for awhile and then dump the contents of the 'hist'
file in the kmalloc event's subdirectory (for readability, a number
of entries have been omitted):
of entries have been omitted)::
# cat /sys/kernel/debug/tracing/events/kmem/kmalloc/hist
# trigger info: hist:keys=call_site:vals=bytes_req:sort=hitcount:size=2048 [active]
......@@ -287,7 +293,7 @@
specified in the trigger, followed by the value(s) also specified in
the trigger. At the beginning of the output is a line that displays
the trigger info, which can also be displayed by reading the
'trigger' file:
'trigger' file::
# cat /sys/kernel/debug/tracing/events/kmem/kmalloc/trigger
hist:keys=call_site:vals=bytes_req:sort=hitcount:size=2048 [active]
......@@ -317,7 +323,7 @@
frequencies.
To turn the hist trigger off, simply call up the trigger in the
command history and re-execute it with a '!' prepended:
command history and re-execute it with a '!' prepended::
# echo '!hist:key=call_site:val=bytes_req' > \
/sys/kernel/debug/tracing/events/kmem/kmalloc/trigger
......@@ -325,7 +331,7 @@
Finally, notice that the call_site as displayed in the output above
isn't really very useful. It's an address, but normally addresses
are displayed in hex. To have a numeric field displayed as a hex
value, simply append '.hex' to the field name in the trigger:
value, simply append '.hex' to the field name in the trigger::
# echo 'hist:key=call_site.hex:val=bytes_req' > \
/sys/kernel/debug/tracing/events/kmem/kmalloc/trigger
......@@ -370,7 +376,7 @@
when looking at text addresses are the corresponding symbols
instead. To have an address displayed as symbolic value instead,
simply append '.sym' or '.sym-offset' to the field name in the
trigger:
trigger::
# echo 'hist:key=call_site.sym:val=bytes_req' > \
/sys/kernel/debug/tracing/events/kmem/kmalloc/trigger
......@@ -420,7 +426,7 @@
run. If instead we we wanted to see the top kmalloc callers in
terms of the number of bytes requested rather than the number of
calls, and we wanted the top caller to appear at the top, we can use
the 'sort' parameter, along with the 'descending' modifier:
the 'sort' parameter, along with the 'descending' modifier::
# echo 'hist:key=call_site.sym:val=bytes_req:sort=bytes_req.descending' > \
/sys/kernel/debug/tracing/events/kmem/kmalloc/trigger
......@@ -461,7 +467,7 @@
Dropped: 0
To display the offset and size information in addition to the symbol
name, just use 'sym-offset' instead:
name, just use 'sym-offset' instead::
# echo 'hist:key=call_site.sym-offset:val=bytes_req:sort=bytes_req.descending' > \
/sys/kernel/debug/tracing/events/kmem/kmalloc/trigger
......@@ -500,7 +506,7 @@
We can also add multiple fields to the 'values' parameter. For
example, we might want to see the total number of bytes allocated
alongside bytes requested, and display the result sorted by bytes
allocated in a descending order:
allocated in a descending order::
# echo 'hist:keys=call_site.sym:values=bytes_req,bytes_alloc:sort=bytes_alloc.descending' > \
/sys/kernel/debug/tracing/events/kmem/kmalloc/trigger
......@@ -543,7 +549,7 @@
the hist trigger display symbolic call_sites, we can have the hist
trigger additionally display the complete set of kernel stack traces
that led to each call_site. To do that, we simply use the special
value 'stacktrace' for the key parameter:
value 'stacktrace' for the key parameter::
# echo 'hist:keys=stacktrace:values=bytes_req,bytes_alloc:sort=bytes_alloc' > \
/sys/kernel/debug/tracing/events/kmem/kmalloc/trigger
......@@ -554,7 +560,7 @@
event, along with a running total of any of the event fields for
that event. Here we tally bytes requested and bytes allocated for
every callpath in the system that led up to a kmalloc (in this case
every callpath to a kmalloc for a kernel compile):
every callpath to a kmalloc for a kernel compile)::
# cat /sys/kernel/debug/tracing/events/kmem/kmalloc/hist
# trigger info: hist:keys=stacktrace:vals=bytes_req,bytes_alloc:sort=bytes_alloc:size=2048 [active]
......@@ -652,7 +658,7 @@
gather and display sorted totals for each process, you can use the
special .execname modifier to display the executable names for the
processes in the table rather than raw pids. The example below
keeps a per-process sum of total bytes read:
keeps a per-process sum of total bytes read::
# echo 'hist:key=common_pid.execname:val=count:sort=count.descending' > \
/sys/kernel/debug/tracing/events/syscalls/sys_enter_read/trigger
......@@ -693,7 +699,7 @@
gather and display a list of systemwide syscall hits, you can use
the special .syscall modifier to display the syscall names rather
than raw ids. The example below keeps a running total of syscall
counts for the system during the run:
counts for the system during the run::
# echo 'hist:key=id.syscall:val=hitcount' > \
/sys/kernel/debug/tracing/events/raw_syscalls/sys_enter/trigger
......@@ -735,19 +741,19 @@
Entries: 72
Dropped: 0
The syscall counts above provide a rough overall picture of system
call activity on the system; we can see for example that the most
popular system call on this system was the 'sys_ioctl' system call.
The syscall counts above provide a rough overall picture of system
call activity on the system; we can see for example that the most
popular system call on this system was the 'sys_ioctl' system call.
We can use 'compound' keys to refine that number and provide some
further insight as to which processes exactly contribute to the
overall ioctl count.
We can use 'compound' keys to refine that number and provide some
further insight as to which processes exactly contribute to the
overall ioctl count.
The command below keeps a hitcount for every unique combination of
system call id and pid - the end result is essentially a table
that keeps a per-pid sum of system call hits. The results are
sorted using the system call id as the primary key, and the
hitcount sum as the secondary key:
The command below keeps a hitcount for every unique combination of
system call id and pid - the end result is essentially a table
that keeps a per-pid sum of system call hits. The results are
sorted using the system call id as the primary key, and the
hitcount sum as the secondary key::
# echo 'hist:key=id.syscall,common_pid.execname:val=hitcount:sort=id,hitcount' > \
/sys/kernel/debug/tracing/events/raw_syscalls/sys_enter/trigger
......@@ -793,11 +799,11 @@
Entries: 323
Dropped: 0
The above list does give us a breakdown of the ioctl syscall by
pid, but it also gives us quite a bit more than that, which we
don't really care about at the moment. Since we know the syscall
id for sys_ioctl (16, displayed next to the sys_ioctl name), we
can use that to filter out all the other syscalls:
The above list does give us a breakdown of the ioctl syscall by
pid, but it also gives us quite a bit more than that, which we
don't really care about at the moment. Since we know the syscall
id for sys_ioctl (16, displayed next to the sys_ioctl name), we
can use that to filter out all the other syscalls::
# echo 'hist:key=id.syscall,common_pid.execname:val=hitcount:sort=id,hitcount if id == 16' > \
/sys/kernel/debug/tracing/events/raw_syscalls/sys_enter/trigger
......@@ -829,18 +835,18 @@
Entries: 103
Dropped: 0
The above output shows that 'compiz' and 'Xorg' are far and away
the heaviest ioctl callers (which might lead to questions about
whether they really need to be making all those calls and to
possible avenues for further investigation.)
The above output shows that 'compiz' and 'Xorg' are far and away
the heaviest ioctl callers (which might lead to questions about
whether they really need to be making all those calls and to
possible avenues for further investigation.)
The compound key examples used a key and a sum value (hitcount) to
sort the output, but we can just as easily use two keys instead.
Here's an example where we use a compound key composed of the the
common_pid and size event fields. Sorting with pid as the primary
key and 'size' as the secondary key allows us to display an
ordered summary of the recvfrom sizes, with counts, received by
each process:
The compound key examples used a key and a sum value (hitcount) to
sort the output, but we can just as easily use two keys instead.
Here's an example where we use a compound key composed of the the
common_pid and size event fields. Sorting with pid as the primary
key and 'size' as the secondary key allows us to display an
ordered summary of the recvfrom sizes, with counts, received by
each process::
# echo 'hist:key=common_pid.execname,size:val=hitcount:sort=common_pid,size' > \
/sys/kernel/debug/tracing/events/syscalls/sys_enter_recvfrom/trigger
......@@ -893,7 +899,7 @@
demonstrates how you can manually pause and continue a hist trigger.
In this example, we'll aggregate fork counts and don't expect a
large number of entries in the hash table, so we'll drop it to a
much smaller number, say 256:
much smaller number, say 256::
# echo 'hist:key=child_comm:val=hitcount:size=256' > \
/sys/kernel/debug/tracing/events/sched/sched_process_fork/trigger
......@@ -929,7 +935,7 @@
If we want to pause the hist trigger, we can simply append :pause to
the command that started the trigger. Notice that the trigger info
displays as [paused]:
displays as [paused]::
# echo 'hist:key=child_comm:val=hitcount:size=256:pause' >> \
/sys/kernel/debug/tracing/events/sched/sched_process_fork/trigger
......@@ -966,7 +972,7 @@
To manually continue having the trigger aggregate events, append
:cont instead. Notice that the trigger info displays as [active]
again, and the data has changed:
again, and the data has changed::
# echo 'hist:key=child_comm:val=hitcount:size=256:cont' >> \
/sys/kernel/debug/tracing/events/sched/sched_process_fork/trigger
......@@ -1020,7 +1026,7 @@
wget.
First we set up an initially paused stacktrace trigger on the
netif_receive_skb event:
netif_receive_skb event::
# echo 'hist:key=stacktrace:vals=len:pause' > \
/sys/kernel/debug/tracing/events/net/netif_receive_skb/trigger
......@@ -1031,7 +1037,7 @@
set up on netif_receive_skb if and only if it sees a
sched_process_exec event with a filename of '/usr/bin/wget'. When
that happens, all netif_receive_skb events are aggregated into a
hash table keyed on stacktrace:
hash table keyed on stacktrace::
# echo 'enable_hist:net:netif_receive_skb if filename==/usr/bin/wget' > \
/sys/kernel/debug/tracing/events/sched/sched_process_exec/trigger
......@@ -1039,7 +1045,7 @@
The aggregation continues until the netif_receive_skb is paused
again, which is what the following disable_hist event does by
creating a similar setup on the sched_process_exit event, using the
filter 'comm==wget':
filter 'comm==wget'::
# echo 'disable_hist:net:netif_receive_skb if comm==wget' > \
/sys/kernel/debug/tracing/events/sched/sched_process_exit/trigger
......@@ -1051,7 +1057,7 @@
The overall effect is that netif_receive_skb events are aggregated
into the hash table for only the duration of the wget. Executing a
wget command and then listing the 'hist' file will display the
output generated by the wget command:
output generated by the wget command::
$ wget https://www.kernel.org/pub/linux/kernel/v3.x/patch-3.19.xz
......@@ -1136,13 +1142,13 @@
Suppose we wanted to try another run of the previous example but
this time also wanted to see the complete list of events that went
into the histogram. In order to avoid having to set everything up
again, we can just clear the histogram first:
again, we can just clear the histogram first::
# echo 'hist:key=stacktrace:vals=len:clear' >> \
/sys/kernel/debug/tracing/events/net/netif_receive_skb/trigger
Just to verify that it is in fact cleared, here's what we now see in
the hist file:
the hist file::
# cat /sys/kernel/debug/tracing/events/net/netif_receive_skb/hist
# trigger info: hist:keys=stacktrace:vals=len:sort=hitcount:size=2048 [paused]
......@@ -1156,7 +1162,7 @@
event occurring during the new run, which are in fact the same
events being aggregated into the hash table, we add some additional
'enable_event' events to the triggering sched_process_exec and
sched_process_exit events as such:
sched_process_exit events as such::
# echo 'enable_event:net:netif_receive_skb if filename==/usr/bin/wget' > \
/sys/kernel/debug/tracing/events/sched/sched_process_exec/trigger
......@@ -1167,7 +1173,7 @@
If you read the trigger files for the sched_process_exec and
sched_process_exit triggers, you should see two triggers for each:
one enabling/disabling the hist aggregation and the other
enabling/disabling the logging of events:
enabling/disabling the logging of events::
# cat /sys/kernel/debug/tracing/events/sched/sched_process_exec/trigger
enable_event:net:netif_receive_skb:unlimited if filename==/usr/bin/wget
......@@ -1181,13 +1187,13 @@
sched_process_exit events is hit and matches 'wget', it enables or
disables both the histogram and the event log, and what you end up
with is a hash table and set of events just covering the specified
duration. Run the wget command again:
duration. Run the wget command again::
$ wget https://www.kernel.org/pub/linux/kernel/v3.x/patch-3.19.xz
Displaying the 'hist' file should show something similar to what you
saw in the last run, but this time you should also see the
individual events in the trace file:
individual events in the trace file::
# cat /sys/kernel/debug/tracing/trace
......@@ -1220,7 +1226,7 @@
attached to a given event. This capability can be useful for
creating a set of different summaries derived from the same set of
events, or for comparing the effects of different filters, among
other things.
other things::
# echo 'hist:keys=skbaddr.hex:vals=len if len < 0' >> \
/sys/kernel/debug/tracing/events/net/netif_receive_skb/trigger
......@@ -1241,7 +1247,7 @@
any existing hist triggers beforehand).
Displaying the contents of the 'hist' file for the event shows the
contents of all five histograms:
contents of all five histograms::
# cat /sys/kernel/debug/tracing/events/net/netif_receive_skb/hist
......@@ -1361,7 +1367,7 @@
output of events generated by tracepoints contained inside inline
functions, but names can be used in a hist trigger on any event.
For example, these two triggers when hit will update the same 'len'
field in the shared 'foo' histogram data:
field in the shared 'foo' histogram data::
# echo 'hist:name=foo:keys=skbaddr.hex:vals=len' > \
/sys/kernel/debug/tracing/events/net/netif_receive_skb/trigger
......@@ -1369,7 +1375,7 @@
/sys/kernel/debug/tracing/events/net/netif_rx/trigger
You can see that they're updating common histogram data by reading
each event's hist files at the same time:
each event's hist files at the same time::
# cat /sys/kernel/debug/tracing/events/net/netif_receive_skb/hist;
cat /sys/kernel/debug/tracing/events/net/netif_rx/hist
......@@ -1482,7 +1488,7 @@
And here's an example that shows how to combine histogram data from
any two events even if they don't share any 'compatible' fields
other than 'hitcount' and 'stacktrace'. These commands create a
couple of triggers named 'bar' using those fields:
couple of triggers named 'bar' using those fields::
# echo 'hist:name=bar:key=stacktrace:val=hitcount' > \
/sys/kernel/debug/tracing/events/sched/sched_process_fork/trigger
......@@ -1490,7 +1496,7 @@
/sys/kernel/debug/tracing/events/net/netif_rx/trigger
And displaying the output of either shows some interesting if
somewhat confusing output:
somewhat confusing output::
# cat /sys/kernel/debug/tracing/events/sched/sched_process_fork/hist
# cat /sys/kernel/debug/tracing/events/net/netif_rx/hist
......@@ -1705,7 +1711,7 @@ to any event field.
Either keys or values can be saved and retrieved in this way. This
creates a variable named 'ts0' for a histogram entry with the key
'next_pid':
'next_pid'::
# echo 'hist:keys=next_pid:vals=$ts0:ts0=common_timestamp ... >> \
event/trigger
......@@ -1721,40 +1727,40 @@ Because 'vals=' is used, the common_timestamp variable value above
will also be summed as a normal histogram value would (though for a
timestamp it makes little sense).
The below shows that a key value can also be saved in the same way:
The below shows that a key value can also be saved in the same way::
# echo 'hist:timer_pid=common_pid:key=timer_pid ...' >> event/trigger
If a variable isn't a key variable or prefixed with 'vals=', the
associated event field will be saved in a variable but won't be summed
as a value:
as a value::
# echo 'hist:keys=next_pid:ts1=common_timestamp ...' >> event/trigger
Multiple variables can be assigned at the same time. The below would
result in both ts0 and b being created as variables, with both
common_timestamp and field1 additionally being summed as values:
common_timestamp and field1 additionally being summed as values::
# echo 'hist:keys=pid:vals=$ts0,$b:ts0=common_timestamp,b=field1 ...' >> \
event/trigger
Note that variable assignments can appear either preceding or
following their use. The command below behaves identically to the
command above:
command above::
# echo 'hist:keys=pid:ts0=common_timestamp,b=field1:vals=$ts0,$b ...' >> \
event/trigger
Any number of variables not bound to a 'vals=' prefix can also be
assigned by simply separating them with colons. Below is the same
thing but without the values being summed in the histogram:
thing but without the values being summed in the histogram::
# echo 'hist:keys=pid:ts0=common_timestamp:b=field1 ...' >> event/trigger
Variables set as above can be referenced and used in expressions on
another event.
For example, here's how a latency can be calculated:
For example, here's how a latency can be calculated::
# echo 'hist:keys=pid,prio:ts0=common_timestamp ...' >> event1/trigger
# echo 'hist:keys=next_pid:wakeup_lat=common_timestamp-$ts0 ...' >> event2/trigger
......@@ -1764,7 +1770,7 @@ variable ts0. In the next line, ts0 is subtracted from the second
event's timestamp to produce the latency, which is then assigned into
yet another variable, 'wakeup_lat'. The hist trigger below in turn
makes use of the wakeup_lat variable to compute a combined latency
using the same key and variable from yet another event:
using the same key and variable from yet another event::
# echo 'hist:key=pid:wakeupswitch_lat=$wakeup_lat+$switchtime_lat ...' >> event3/trigger
......@@ -1784,7 +1790,7 @@ separated by semicolons, to the tracing/synthetic_events file.
For instance, the following creates a new event named 'wakeup_latency'
with 3 fields: lat, pid, and prio. Each of those fields is simply a
variable reference to a variable on another event:
variable reference to a variable on another event::
# echo 'wakeup_latency \
u64 lat; \
......@@ -1793,13 +1799,13 @@ variable reference to a variable on another event:
/sys/kernel/debug/tracing/synthetic_events
Reading the tracing/synthetic_events file lists all the currently
defined synthetic events, in this case the event defined above:
defined synthetic events, in this case the event defined above::
# cat /sys/kernel/debug/tracing/synthetic_events
wakeup_latency u64 lat; pid_t pid; int prio
An existing synthetic event definition can be removed by prepending
the command that defined it with a '!':
the command that defined it with a '!'::
# echo '!wakeup_latency u64 lat pid_t pid int prio' >> \
/sys/kernel/debug/tracing/synthetic_events
......@@ -1811,13 +1817,13 @@ and variables defined on other events (see Section 2.2.3 below on
how that is done using hist trigger 'onmatch' action). Once that is
done, the 'wakeup_latency' synthetic event instance is created.
A histogram can now be defined for the new synthetic event:
A histogram can now be defined for the new synthetic event::
# echo 'hist:keys=pid,prio,lat.log2:sort=pid,lat' >> \
/sys/kernel/debug/tracing/events/synthetic/wakeup_latency/trigger
The new event is created under the tracing/events/synthetic/ directory
and looks and behaves just like any other event:
and looks and behaves just like any other event::
# ls /sys/kernel/debug/tracing/events/synthetic/wakeup_latency
enable filter format hist id trigger
......@@ -1872,74 +1878,74 @@ hist trigger specification.
As an example the below defines a simple synthetic event and uses
a variable defined on the sched_wakeup_new event as a parameter
when invoking the synthetic event. Here we define the synthetic
event:
event::
# echo 'wakeup_new_test pid_t pid' >> \
/sys/kernel/debug/tracing/synthetic_events
# echo 'wakeup_new_test pid_t pid' >> \
/sys/kernel/debug/tracing/synthetic_events
# cat /sys/kernel/debug/tracing/synthetic_events
wakeup_new_test pid_t pid
# cat /sys/kernel/debug/tracing/synthetic_events
wakeup_new_test pid_t pid
The following hist trigger both defines the missing testpid
variable and specifies an onmatch() action that generates a
wakeup_new_test synthetic event whenever a sched_wakeup_new event
occurs, which because of the 'if comm == "cyclictest"' filter only
happens when the executable is cyclictest:
happens when the executable is cyclictest::
# echo 'hist:keys=$testpid:testpid=pid:onmatch(sched.sched_wakeup_new).\
wakeup_new_test($testpid) if comm=="cyclictest"' >> \
/sys/kernel/debug/tracing/events/sched/sched_wakeup_new/trigger
# echo 'hist:keys=$testpid:testpid=pid:onmatch(sched.sched_wakeup_new).\
wakeup_new_test($testpid) if comm=="cyclictest"' >> \
/sys/kernel/debug/tracing/events/sched/sched_wakeup_new/trigger
Creating and displaying a histogram based on those events is now
just a matter of using the fields and new synthetic event in the
tracing/events/synthetic directory, as usual:
tracing/events/synthetic directory, as usual::
# echo 'hist:keys=pid:sort=pid' >> \
/sys/kernel/debug/tracing/events/synthetic/wakeup_new_test/trigger
# echo 'hist:keys=pid:sort=pid' >> \
/sys/kernel/debug/tracing/events/synthetic/wakeup_new_test/trigger
Running 'cyclictest' should cause wakeup_new events to generate
wakeup_new_test synthetic events which should result in histogram
output in the wakeup_new_test event's hist file:
output in the wakeup_new_test event's hist file::
# cat /sys/kernel/debug/tracing/events/synthetic/wakeup_new_test/hist
# cat /sys/kernel/debug/tracing/events/synthetic/wakeup_new_test/hist
A more typical usage would be to use two events to calculate a
latency. The following example uses a set of hist triggers to
produce a 'wakeup_latency' histogram:
produce a 'wakeup_latency' histogram.
First, we define a 'wakeup_latency' synthetic event:
First, we define a 'wakeup_latency' synthetic event::
# echo 'wakeup_latency u64 lat; pid_t pid; int prio' >> \
/sys/kernel/debug/tracing/synthetic_events
# echo 'wakeup_latency u64 lat; pid_t pid; int prio' >> \
/sys/kernel/debug/tracing/synthetic_events
Next, we specify that whenever we see a sched_waking event for a
cyclictest thread, save the timestamp in a 'ts0' variable:
cyclictest thread, save the timestamp in a 'ts0' variable::
# echo 'hist:keys=$saved_pid:saved_pid=pid:ts0=common_timestamp.usecs \
if comm=="cyclictest"' >> \
/sys/kernel/debug/tracing/events/sched/sched_waking/trigger
# echo 'hist:keys=$saved_pid:saved_pid=pid:ts0=common_timestamp.usecs \
if comm=="cyclictest"' >> \
/sys/kernel/debug/tracing/events/sched/sched_waking/trigger
Then, when the corresponding thread is actually scheduled onto the
CPU by a sched_switch event, calculate the latency and use that
along with another variable and an event field to generate a
wakeup_latency synthetic event:
wakeup_latency synthetic event::
# echo 'hist:keys=next_pid:wakeup_lat=common_timestamp.usecs-$ts0:\
onmatch(sched.sched_waking).wakeup_latency($wakeup_lat,\
$saved_pid,next_prio) if next_comm=="cyclictest"' >> \
/sys/kernel/debug/tracing/events/sched/sched_switch/trigger
# echo 'hist:keys=next_pid:wakeup_lat=common_timestamp.usecs-$ts0:\
onmatch(sched.sched_waking).wakeup_latency($wakeup_lat,\
$saved_pid,next_prio) if next_comm=="cyclictest"' >> \
/sys/kernel/debug/tracing/events/sched/sched_switch/trigger
We also need to create a histogram on the wakeup_latency synthetic
event in order to aggregate the generated synthetic event data:
event in order to aggregate the generated synthetic event data::
# echo 'hist:keys=pid,prio,lat:sort=pid,lat' >> \
/sys/kernel/debug/tracing/events/synthetic/wakeup_latency/trigger
# echo 'hist:keys=pid,prio,lat:sort=pid,lat' >> \
/sys/kernel/debug/tracing/events/synthetic/wakeup_latency/trigger
Finally, once we've run cyclictest to actually generate some
events, we can see the output by looking at the wakeup_latency
synthetic event's hist file:
synthetic event's hist file::
# cat /sys/kernel/debug/tracing/events/synthetic/wakeup_latency/hist
# cat /sys/kernel/debug/tracing/events/synthetic/wakeup_latency/hist
- onmax(var).save(field,.. .)
......@@ -1961,38 +1967,38 @@ hist trigger specification.
back to that pid, the timestamp difference is calculated. If the
resulting latency, stored in wakeup_lat, exceeds the current
maximum latency, the values specified in the save() fields are
recorded:
recorded::
# echo 'hist:keys=pid:ts0=common_timestamp.usecs \
if comm=="cyclictest"' >> \
/sys/kernel/debug/tracing/events/sched/sched_waking/trigger
# echo 'hist:keys=pid:ts0=common_timestamp.usecs \
if comm=="cyclictest"' >> \
/sys/kernel/debug/tracing/events/sched/sched_waking/trigger
# echo 'hist:keys=next_pid:\
wakeup_lat=common_timestamp.usecs-$ts0:\
onmax($wakeup_lat).save(next_comm,prev_pid,prev_prio,prev_comm) \
if next_comm=="cyclictest"' >> \
/sys/kernel/debug/tracing/events/sched/sched_switch/trigger
# echo 'hist:keys=next_pid:\
wakeup_lat=common_timestamp.usecs-$ts0:\
onmax($wakeup_lat).save(next_comm,prev_pid,prev_prio,prev_comm) \
if next_comm=="cyclictest"' >> \
/sys/kernel/debug/tracing/events/sched/sched_switch/trigger
When the histogram is displayed, the max value and the saved
values corresponding to the max are displayed following the rest
of the fields:
of the fields::
# cat /sys/kernel/debug/tracing/events/sched/sched_switch/hist
{ next_pid: 2255 } hitcount: 239
common_timestamp-ts0: 0
max: 27
next_comm: cyclictest
prev_pid: 0 prev_prio: 120 prev_comm: swapper/1
# cat /sys/kernel/debug/tracing/events/sched/sched_switch/hist
{ next_pid: 2255 } hitcount: 239
common_timestamp-ts0: 0
max: 27
next_comm: cyclictest
prev_pid: 0 prev_prio: 120 prev_comm: swapper/1
{ next_pid: 2256 } hitcount: 2355
common_timestamp-ts0: 0
max: 49 next_comm: cyclictest
prev_pid: 0 prev_prio: 120 prev_comm: swapper/0
{ next_pid: 2256 } hitcount: 2355
common_timestamp-ts0: 0
max: 49 next_comm: cyclictest
prev_pid: 0 prev_prio: 120 prev_comm: swapper/0
Totals:
Hits: 12970
Entries: 2
Dropped: 0
Totals:
Hits: 12970
Entries: 2
Dropped: 0
3. User space creating a trigger
--------------------------------
......@@ -2002,24 +2008,24 @@ ring buffer. This can also act like an event, by writing into the trigger
file located in /sys/kernel/tracing/events/ftrace/print/
Modifying cyclictest to write into the trace_marker file before it sleeps
and after it wakes up, something like this:
and after it wakes up, something like this::
static void traceputs(char *str)
{
static void traceputs(char *str)
{
/* tracemark_fd is the trace_marker file descriptor */
if (tracemark_fd < 0)
return;
/* write the tracemark message */
write(tracemark_fd, str, strlen(str));
}
}
And later add something like:
And later add something like::
traceputs("start");
clock_nanosleep(...);
traceputs("end");
We can make a histogram from this:
We can make a histogram from this::
# cd /sys/kernel/tracing
# echo 'latency u64 lat' > synthetic_events
......@@ -2034,7 +2040,7 @@ it will call the "latency" synthetic event with the calculated latency as its
parameter. Finally, a histogram is added to the latency synthetic event to
record the calculated latency along with the pid.
Now running cyclictest with:
Now running cyclictest with::
# ./cyclictest -p80 -d0 -i250 -n -a -t --tracemark -b 1000
......@@ -2049,297 +2055,297 @@ Now running cyclictest with:
Note, the -b 1000 is used just to make --tracemark available.
Then we can see the histogram created by this with:
Then we can see the histogram created by this with::
# cat events/synthetic/latency/hist
# event histogram
#
# trigger info: hist:keys=lat,common_pid:vals=hitcount:sort=lat:size=2048 [active]
#
{ lat: 107, common_pid: 2039 } hitcount: 1
{ lat: 122, common_pid: 2041 } hitcount: 1
{ lat: 166, common_pid: 2039 } hitcount: 1
{ lat: 174, common_pid: 2039 } hitcount: 1
{ lat: 194, common_pid: 2041 } hitcount: 1
{ lat: 196, common_pid: 2036 } hitcount: 1
{ lat: 197, common_pid: 2038 } hitcount: 1
{ lat: 198, common_pid: 2039 } hitcount: 1
{ lat: 199, common_pid: 2039 } hitcount: 1
{ lat: 200, common_pid: 2041 } hitcount: 1
{ lat: 201, common_pid: 2039 } hitcount: 2
{ lat: 202, common_pid: 2038 } hitcount: 1
{ lat: 202, common_pid: 2043 } hitcount: 1
{ lat: 203, common_pid: 2039 } hitcount: 1
{ lat: 203, common_pid: 2036 } hitcount: 1
{ lat: 203, common_pid: 2041 } hitcount: 1
{ lat: 206, common_pid: 2038 } hitcount: 2
{ lat: 207, common_pid: 2039 } hitcount: 1
{ lat: 207, common_pid: 2036 } hitcount: 1
{ lat: 208, common_pid: 2040 } hitcount: 1
{ lat: 209, common_pid: 2043 } hitcount: 1
{ lat: 210, common_pid: 2039 } hitcount: 1
{ lat: 211, common_pid: 2039 } hitcount: 4
{ lat: 212, common_pid: 2043 } hitcount: 1
{ lat: 212, common_pid: 2039 } hitcount: 2
{ lat: 213, common_pid: 2039 } hitcount: 1
{ lat: 214, common_pid: 2038 } hitcount: 1
{ lat: 214, common_pid: 2039 } hitcount: 2
{ lat: 214, common_pid: 2042 } hitcount: 1
{ lat: 215, common_pid: 2039 } hitcount: 1
{ lat: 217, common_pid: 2036 } hitcount: 1
{ lat: 217, common_pid: 2040 } hitcount: 1
{ lat: 217, common_pid: 2039 } hitcount: 1
{ lat: 218, common_pid: 2039 } hitcount: 6
{ lat: 219, common_pid: 2039 } hitcount: 9
{ lat: 220, common_pid: 2039 } hitcount: 11
{ lat: 221, common_pid: 2039 } hitcount: 5
{ lat: 221, common_pid: 2042 } hitcount: 1
{ lat: 222, common_pid: 2039 } hitcount: 7
{ lat: 223, common_pid: 2036 } hitcount: 1
{ lat: 223, common_pid: 2039 } hitcount: 3
{ lat: 224, common_pid: 2039 } hitcount: 4
{ lat: 224, common_pid: 2037 } hitcount: 1
{ lat: 224, common_pid: 2036 } hitcount: 2
{ lat: 225, common_pid: 2039 } hitcount: 5
{ lat: 225, common_pid: 2042 } hitcount: 1
{ lat: 226, common_pid: 2039 } hitcount: 7
{ lat: 226, common_pid: 2036 } hitcount: 4
{ lat: 227, common_pid: 2039 } hitcount: 6
{ lat: 227, common_pid: 2036 } hitcount: 12
{ lat: 227, common_pid: 2043 } hitcount: 1
{ lat: 228, common_pid: 2039 } hitcount: 7
{ lat: 228, common_pid: 2036 } hitcount: 14
{ lat: 229, common_pid: 2039 } hitcount: 9
{ lat: 229, common_pid: 2036 } hitcount: 8
{ lat: 229, common_pid: 2038 } hitcount: 1
{ lat: 230, common_pid: 2039 } hitcount: 11
{ lat: 230, common_pid: 2036 } hitcount: 6
{ lat: 230, common_pid: 2043 } hitcount: 1
{ lat: 230, common_pid: 2042 } hitcount: 2
{ lat: 231, common_pid: 2041 } hitcount: 1
{ lat: 231, common_pid: 2036 } hitcount: 6
{ lat: 231, common_pid: 2043 } hitcount: 1
{ lat: 231, common_pid: 2039 } hitcount: 8
{ lat: 232, common_pid: 2037 } hitcount: 1
{ lat: 232, common_pid: 2039 } hitcount: 6
{ lat: 232, common_pid: 2040 } hitcount: 2
{ lat: 232, common_pid: 2036 } hitcount: 5
{ lat: 232, common_pid: 2043 } hitcount: 1
{ lat: 233, common_pid: 2036 } hitcount: 5
{ lat: 233, common_pid: 2039 } hitcount: 11
{ lat: 234, common_pid: 2039 } hitcount: 4
{ lat: 234, common_pid: 2038 } hitcount: 2
{ lat: 234, common_pid: 2043 } hitcount: 2
{ lat: 234, common_pid: 2036 } hitcount: 11
{ lat: 234, common_pid: 2040 } hitcount: 1
{ lat: 235, common_pid: 2037 } hitcount: 2
{ lat: 235, common_pid: 2036 } hitcount: 8
{ lat: 235, common_pid: 2043 } hitcount: 2
{ lat: 235, common_pid: 2039 } hitcount: 5
{ lat: 235, common_pid: 2042 } hitcount: 2
{ lat: 235, common_pid: 2040 } hitcount: 4
{ lat: 235, common_pid: 2041 } hitcount: 1
{ lat: 236, common_pid: 2036 } hitcount: 7
{ lat: 236, common_pid: 2037 } hitcount: 1
{ lat: 236, common_pid: 2041 } hitcount: 5
{ lat: 236, common_pid: 2039 } hitcount: 3
{ lat: 236, common_pid: 2043 } hitcount: 9
{ lat: 236, common_pid: 2040 } hitcount: 7
{ lat: 237, common_pid: 2037 } hitcount: 1
{ lat: 237, common_pid: 2040 } hitcount: 1
{ lat: 237, common_pid: 2036 } hitcount: 9
{ lat: 237, common_pid: 2039 } hitcount: 3
{ lat: 237, common_pid: 2043 } hitcount: 8
{ lat: 237, common_pid: 2042 } hitcount: 2
{ lat: 237, common_pid: 2041 } hitcount: 2
{ lat: 238, common_pid: 2043 } hitcount: 10
{ lat: 238, common_pid: 2040 } hitcount: 1
{ lat: 238, common_pid: 2037 } hitcount: 9
{ lat: 238, common_pid: 2038 } hitcount: 1
{ lat: 238, common_pid: 2039 } hitcount: 1
{ lat: 238, common_pid: 2042 } hitcount: 3
{ lat: 238, common_pid: 2036 } hitcount: 7
{ lat: 239, common_pid: 2041 } hitcount: 1
{ lat: 239, common_pid: 2043 } hitcount: 11
{ lat: 239, common_pid: 2037 } hitcount: 11
{ lat: 239, common_pid: 2038 } hitcount: 6
{ lat: 239, common_pid: 2036 } hitcount: 7
{ lat: 239, common_pid: 2040 } hitcount: 1
{ lat: 239, common_pid: 2042 } hitcount: 9
{ lat: 240, common_pid: 2037 } hitcount: 29
{ lat: 240, common_pid: 2043 } hitcount: 15
{ lat: 240, common_pid: 2040 } hitcount: 44
{ lat: 240, common_pid: 2039 } hitcount: 1
{ lat: 240, common_pid: 2041 } hitcount: 2
{ lat: 240, common_pid: 2038 } hitcount: 1
{ lat: 240, common_pid: 2036 } hitcount: 10
{ lat: 240, common_pid: 2042 } hitcount: 13
{ lat: 241, common_pid: 2036 } hitcount: 21
{ lat: 241, common_pid: 2041 } hitcount: 36
{ lat: 241, common_pid: 2037 } hitcount: 34
{ lat: 241, common_pid: 2042 } hitcount: 14
{ lat: 241, common_pid: 2040 } hitcount: 94
{ lat: 241, common_pid: 2039 } hitcount: 12
{ lat: 241, common_pid: 2038 } hitcount: 2
{ lat: 241, common_pid: 2043 } hitcount: 28
{ lat: 242, common_pid: 2040 } hitcount: 109
{ lat: 242, common_pid: 2041 } hitcount: 506
{ lat: 242, common_pid: 2039 } hitcount: 155
{ lat: 242, common_pid: 2042 } hitcount: 21
{ lat: 242, common_pid: 2037 } hitcount: 52
{ lat: 242, common_pid: 2043 } hitcount: 21
{ lat: 242, common_pid: 2036 } hitcount: 16
{ lat: 242, common_pid: 2038 } hitcount: 156
{ lat: 243, common_pid: 2037 } hitcount: 46
{ lat: 243, common_pid: 2039 } hitcount: 40
{ lat: 243, common_pid: 2042 } hitcount: 119
{ lat: 243, common_pid: 2041 } hitcount: 611
{ lat: 243, common_pid: 2036 } hitcount: 69
{ lat: 243, common_pid: 2038 } hitcount: 784
{ lat: 243, common_pid: 2040 } hitcount: 323
{ lat: 243, common_pid: 2043 } hitcount: 14
{ lat: 244, common_pid: 2043 } hitcount: 35
{ lat: 244, common_pid: 2042 } hitcount: 305
{ lat: 244, common_pid: 2039 } hitcount: 8
{ lat: 244, common_pid: 2040 } hitcount: 4515
{ lat: 244, common_pid: 2038 } hitcount: 371
{ lat: 244, common_pid: 2037 } hitcount: 31
{ lat: 244, common_pid: 2036 } hitcount: 114
{ lat: 244, common_pid: 2041 } hitcount: 3396
{ lat: 245, common_pid: 2036 } hitcount: 700
{ lat: 245, common_pid: 2041 } hitcount: 2772
{ lat: 245, common_pid: 2037 } hitcount: 268
{ lat: 245, common_pid: 2039 } hitcount: 472
{ lat: 245, common_pid: 2038 } hitcount: 2758
{ lat: 245, common_pid: 2042 } hitcount: 3833
{ lat: 245, common_pid: 2040 } hitcount: 3105
{ lat: 245, common_pid: 2043 } hitcount: 645
{ lat: 246, common_pid: 2038 } hitcount: 3451
{ lat: 246, common_pid: 2041 } hitcount: 142
{ lat: 246, common_pid: 2037 } hitcount: 5101
{ lat: 246, common_pid: 2040 } hitcount: 68
{ lat: 246, common_pid: 2043 } hitcount: 5099
{ lat: 246, common_pid: 2039 } hitcount: 5608
{ lat: 246, common_pid: 2042 } hitcount: 3723
{ lat: 246, common_pid: 2036 } hitcount: 4738
{ lat: 247, common_pid: 2042 } hitcount: 312
{ lat: 247, common_pid: 2043 } hitcount: 2385
{ lat: 247, common_pid: 2041 } hitcount: 452
{ lat: 247, common_pid: 2038 } hitcount: 792
{ lat: 247, common_pid: 2040 } hitcount: 78
{ lat: 247, common_pid: 2036 } hitcount: 2375
{ lat: 247, common_pid: 2039 } hitcount: 1834
{ lat: 247, common_pid: 2037 } hitcount: 2655
{ lat: 248, common_pid: 2037 } hitcount: 36
{ lat: 248, common_pid: 2042 } hitcount: 11
{ lat: 248, common_pid: 2038 } hitcount: 122
{ lat: 248, common_pid: 2036 } hitcount: 135
{ lat: 248, common_pid: 2039 } hitcount: 26
{ lat: 248, common_pid: 2041 } hitcount: 503
{ lat: 248, common_pid: 2043 } hitcount: 66
{ lat: 248, common_pid: 2040 } hitcount: 46
{ lat: 249, common_pid: 2037 } hitcount: 29
{ lat: 249, common_pid: 2038 } hitcount: 1
{ lat: 249, common_pid: 2043 } hitcount: 29
{ lat: 249, common_pid: 2039 } hitcount: 8
{ lat: 249, common_pid: 2042 } hitcount: 56
{ lat: 249, common_pid: 2040 } hitcount: 27
{ lat: 249, common_pid: 2041 } hitcount: 11
{ lat: 249, common_pid: 2036 } hitcount: 27
{ lat: 250, common_pid: 2038 } hitcount: 1
{ lat: 250, common_pid: 2036 } hitcount: 30
{ lat: 250, common_pid: 2040 } hitcount: 19
{ lat: 250, common_pid: 2043 } hitcount: 22
{ lat: 250, common_pid: 2042 } hitcount: 20
{ lat: 250, common_pid: 2041 } hitcount: 1
{ lat: 250, common_pid: 2039 } hitcount: 6
{ lat: 250, common_pid: 2037 } hitcount: 48
{ lat: 251, common_pid: 2037 } hitcount: 43
{ lat: 251, common_pid: 2039 } hitcount: 1
{ lat: 251, common_pid: 2036 } hitcount: 12
{ lat: 251, common_pid: 2042 } hitcount: 2
{ lat: 251, common_pid: 2041 } hitcount: 1
{ lat: 251, common_pid: 2043 } hitcount: 15
{ lat: 251, common_pid: 2040 } hitcount: 3
{ lat: 252, common_pid: 2040 } hitcount: 1
{ lat: 252, common_pid: 2036 } hitcount: 12
{ lat: 252, common_pid: 2037 } hitcount: 21
{ lat: 252, common_pid: 2043 } hitcount: 14
{ lat: 253, common_pid: 2037 } hitcount: 21
{ lat: 253, common_pid: 2039 } hitcount: 2
{ lat: 253, common_pid: 2036 } hitcount: 9
{ lat: 253, common_pid: 2043 } hitcount: 6
{ lat: 253, common_pid: 2040 } hitcount: 1
{ lat: 254, common_pid: 2036 } hitcount: 8
{ lat: 254, common_pid: 2043 } hitcount: 3
{ lat: 254, common_pid: 2041 } hitcount: 1
{ lat: 254, common_pid: 2042 } hitcount: 1
{ lat: 254, common_pid: 2039 } hitcount: 1
{ lat: 254, common_pid: 2037 } hitcount: 12
{ lat: 255, common_pid: 2043 } hitcount: 1
{ lat: 255, common_pid: 2037 } hitcount: 2
{ lat: 255, common_pid: 2036 } hitcount: 2
{ lat: 255, common_pid: 2039 } hitcount: 8
{ lat: 256, common_pid: 2043 } hitcount: 1
{ lat: 256, common_pid: 2036 } hitcount: 4
{ lat: 256, common_pid: 2039 } hitcount: 6
{ lat: 257, common_pid: 2039 } hitcount: 5
{ lat: 257, common_pid: 2036 } hitcount: 4
{ lat: 258, common_pid: 2039 } hitcount: 5
{ lat: 258, common_pid: 2036 } hitcount: 2
{ lat: 259, common_pid: 2036 } hitcount: 7
{ lat: 259, common_pid: 2039 } hitcount: 7
{ lat: 260, common_pid: 2036 } hitcount: 8
{ lat: 260, common_pid: 2039 } hitcount: 6
{ lat: 261, common_pid: 2036 } hitcount: 5
{ lat: 261, common_pid: 2039 } hitcount: 7
{ lat: 262, common_pid: 2039 } hitcount: 5
{ lat: 262, common_pid: 2036 } hitcount: 5
{ lat: 263, common_pid: 2039 } hitcount: 7
{ lat: 263, common_pid: 2036 } hitcount: 7
{ lat: 264, common_pid: 2039 } hitcount: 9
{ lat: 264, common_pid: 2036 } hitcount: 9
{ lat: 265, common_pid: 2036 } hitcount: 5
{ lat: 265, common_pid: 2039 } hitcount: 1
{ lat: 266, common_pid: 2036 } hitcount: 1
{ lat: 266, common_pid: 2039 } hitcount: 3
{ lat: 267, common_pid: 2036 } hitcount: 1
{ lat: 267, common_pid: 2039 } hitcount: 3
{ lat: 268, common_pid: 2036 } hitcount: 1
{ lat: 268, common_pid: 2039 } hitcount: 6
{ lat: 269, common_pid: 2036 } hitcount: 1
{ lat: 269, common_pid: 2043 } hitcount: 1
{ lat: 269, common_pid: 2039 } hitcount: 2
{ lat: 270, common_pid: 2040 } hitcount: 1
{ lat: 270, common_pid: 2039 } hitcount: 6
{ lat: 271, common_pid: 2041 } hitcount: 1
{ lat: 271, common_pid: 2039 } hitcount: 5
{ lat: 272, common_pid: 2039 } hitcount: 10
{ lat: 273, common_pid: 2039 } hitcount: 8
{ lat: 274, common_pid: 2039 } hitcount: 2
{ lat: 275, common_pid: 2039 } hitcount: 1
{ lat: 276, common_pid: 2039 } hitcount: 2
{ lat: 276, common_pid: 2037 } hitcount: 1
{ lat: 276, common_pid: 2038 } hitcount: 1
{ lat: 277, common_pid: 2039 } hitcount: 1
{ lat: 277, common_pid: 2042 } hitcount: 1
{ lat: 278, common_pid: 2039 } hitcount: 1
{ lat: 279, common_pid: 2039 } hitcount: 4
{ lat: 279, common_pid: 2043 } hitcount: 1
{ lat: 280, common_pid: 2039 } hitcount: 3
{ lat: 283, common_pid: 2036 } hitcount: 2
{ lat: 284, common_pid: 2039 } hitcount: 1
{ lat: 284, common_pid: 2043 } hitcount: 1
{ lat: 288, common_pid: 2039 } hitcount: 1
{ lat: 289, common_pid: 2039 } hitcount: 1
{ lat: 300, common_pid: 2039 } hitcount: 1
{ lat: 384, common_pid: 2039 } hitcount: 1
Totals:
Hits: 67625
Entries: 278
Dropped: 0
# event histogram
#
# trigger info: hist:keys=lat,common_pid:vals=hitcount:sort=lat:size=2048 [active]
#
{ lat: 107, common_pid: 2039 } hitcount: 1
{ lat: 122, common_pid: 2041 } hitcount: 1
{ lat: 166, common_pid: 2039 } hitcount: 1
{ lat: 174, common_pid: 2039 } hitcount: 1
{ lat: 194, common_pid: 2041 } hitcount: 1
{ lat: 196, common_pid: 2036 } hitcount: 1
{ lat: 197, common_pid: 2038 } hitcount: 1
{ lat: 198, common_pid: 2039 } hitcount: 1
{ lat: 199, common_pid: 2039 } hitcount: 1
{ lat: 200, common_pid: 2041 } hitcount: 1
{ lat: 201, common_pid: 2039 } hitcount: 2
{ lat: 202, common_pid: 2038 } hitcount: 1
{ lat: 202, common_pid: 2043 } hitcount: 1
{ lat: 203, common_pid: 2039 } hitcount: 1
{ lat: 203, common_pid: 2036 } hitcount: 1
{ lat: 203, common_pid: 2041 } hitcount: 1
{ lat: 206, common_pid: 2038 } hitcount: 2
{ lat: 207, common_pid: 2039 } hitcount: 1
{ lat: 207, common_pid: 2036 } hitcount: 1
{ lat: 208, common_pid: 2040 } hitcount: 1
{ lat: 209, common_pid: 2043 } hitcount: 1
{ lat: 210, common_pid: 2039 } hitcount: 1
{ lat: 211, common_pid: 2039 } hitcount: 4
{ lat: 212, common_pid: 2043 } hitcount: 1
{ lat: 212, common_pid: 2039 } hitcount: 2
{ lat: 213, common_pid: 2039 } hitcount: 1
{ lat: 214, common_pid: 2038 } hitcount: 1
{ lat: 214, common_pid: 2039 } hitcount: 2
{ lat: 214, common_pid: 2042 } hitcount: 1
{ lat: 215, common_pid: 2039 } hitcount: 1
{ lat: 217, common_pid: 2036 } hitcount: 1
{ lat: 217, common_pid: 2040 } hitcount: 1
{ lat: 217, common_pid: 2039 } hitcount: 1
{ lat: 218, common_pid: 2039 } hitcount: 6
{ lat: 219, common_pid: 2039 } hitcount: 9
{ lat: 220, common_pid: 2039 } hitcount: 11
{ lat: 221, common_pid: 2039 } hitcount: 5
{ lat: 221, common_pid: 2042 } hitcount: 1
{ lat: 222, common_pid: 2039 } hitcount: 7
{ lat: 223, common_pid: 2036 } hitcount: 1
{ lat: 223, common_pid: 2039 } hitcount: 3
{ lat: 224, common_pid: 2039 } hitcount: 4
{ lat: 224, common_pid: 2037 } hitcount: 1
{ lat: 224, common_pid: 2036 } hitcount: 2
{ lat: 225, common_pid: 2039 } hitcount: 5
{ lat: 225, common_pid: 2042 } hitcount: 1
{ lat: 226, common_pid: 2039 } hitcount: 7
{ lat: 226, common_pid: 2036 } hitcount: 4
{ lat: 227, common_pid: 2039 } hitcount: 6
{ lat: 227, common_pid: 2036 } hitcount: 12
{ lat: 227, common_pid: 2043 } hitcount: 1
{ lat: 228, common_pid: 2039 } hitcount: 7
{ lat: 228, common_pid: 2036 } hitcount: 14
{ lat: 229, common_pid: 2039 } hitcount: 9
{ lat: 229, common_pid: 2036 } hitcount: 8
{ lat: 229, common_pid: 2038 } hitcount: 1
{ lat: 230, common_pid: 2039 } hitcount: 11
{ lat: 230, common_pid: 2036 } hitcount: 6
{ lat: 230, common_pid: 2043 } hitcount: 1
{ lat: 230, common_pid: 2042 } hitcount: 2
{ lat: 231, common_pid: 2041 } hitcount: 1
{ lat: 231, common_pid: 2036 } hitcount: 6
{ lat: 231, common_pid: 2043 } hitcount: 1
{ lat: 231, common_pid: 2039 } hitcount: 8
{ lat: 232, common_pid: 2037 } hitcount: 1
{ lat: 232, common_pid: 2039 } hitcount: 6
{ lat: 232, common_pid: 2040 } hitcount: 2
{ lat: 232, common_pid: 2036 } hitcount: 5
{ lat: 232, common_pid: 2043 } hitcount: 1
{ lat: 233, common_pid: 2036 } hitcount: 5
{ lat: 233, common_pid: 2039 } hitcount: 11
{ lat: 234, common_pid: 2039 } hitcount: 4
{ lat: 234, common_pid: 2038 } hitcount: 2
{ lat: 234, common_pid: 2043 } hitcount: 2
{ lat: 234, common_pid: 2036 } hitcount: 11
{ lat: 234, common_pid: 2040 } hitcount: 1
{ lat: 235, common_pid: 2037 } hitcount: 2
{ lat: 235, common_pid: 2036 } hitcount: 8
{ lat: 235, common_pid: 2043 } hitcount: 2
{ lat: 235, common_pid: 2039 } hitcount: 5
{ lat: 235, common_pid: 2042 } hitcount: 2
{ lat: 235, common_pid: 2040 } hitcount: 4
{ lat: 235, common_pid: 2041 } hitcount: 1
{ lat: 236, common_pid: 2036 } hitcount: 7
{ lat: 236, common_pid: 2037 } hitcount: 1
{ lat: 236, common_pid: 2041 } hitcount: 5
{ lat: 236, common_pid: 2039 } hitcount: 3
{ lat: 236, common_pid: 2043 } hitcount: 9
{ lat: 236, common_pid: 2040 } hitcount: 7
{ lat: 237, common_pid: 2037 } hitcount: 1
{ lat: 237, common_pid: 2040 } hitcount: 1
{ lat: 237, common_pid: 2036 } hitcount: 9
{ lat: 237, common_pid: 2039 } hitcount: 3
{ lat: 237, common_pid: 2043 } hitcount: 8
{ lat: 237, common_pid: 2042 } hitcount: 2
{ lat: 237, common_pid: 2041 } hitcount: 2
{ lat: 238, common_pid: 2043 } hitcount: 10
{ lat: 238, common_pid: 2040 } hitcount: 1
{ lat: 238, common_pid: 2037 } hitcount: 9
{ lat: 238, common_pid: 2038 } hitcount: 1
{ lat: 238, common_pid: 2039 } hitcount: 1
{ lat: 238, common_pid: 2042 } hitcount: 3
{ lat: 238, common_pid: 2036 } hitcount: 7
{ lat: 239, common_pid: 2041 } hitcount: 1
{ lat: 239, common_pid: 2043 } hitcount: 11
{ lat: 239, common_pid: 2037 } hitcount: 11
{ lat: 239, common_pid: 2038 } hitcount: 6
{ lat: 239, common_pid: 2036 } hitcount: 7
{ lat: 239, common_pid: 2040 } hitcount: 1
{ lat: 239, common_pid: 2042 } hitcount: 9
{ lat: 240, common_pid: 2037 } hitcount: 29
{ lat: 240, common_pid: 2043 } hitcount: 15
{ lat: 240, common_pid: 2040 } hitcount: 44
{ lat: 240, common_pid: 2039 } hitcount: 1
{ lat: 240, common_pid: 2041 } hitcount: 2
{ lat: 240, common_pid: 2038 } hitcount: 1
{ lat: 240, common_pid: 2036 } hitcount: 10
{ lat: 240, common_pid: 2042 } hitcount: 13
{ lat: 241, common_pid: 2036 } hitcount: 21
{ lat: 241, common_pid: 2041 } hitcount: 36
{ lat: 241, common_pid: 2037 } hitcount: 34
{ lat: 241, common_pid: 2042 } hitcount: 14
{ lat: 241, common_pid: 2040 } hitcount: 94
{ lat: 241, common_pid: 2039 } hitcount: 12
{ lat: 241, common_pid: 2038 } hitcount: 2
{ lat: 241, common_pid: 2043 } hitcount: 28
{ lat: 242, common_pid: 2040 } hitcount: 109
{ lat: 242, common_pid: 2041 } hitcount: 506
{ lat: 242, common_pid: 2039 } hitcount: 155
{ lat: 242, common_pid: 2042 } hitcount: 21
{ lat: 242, common_pid: 2037 } hitcount: 52
{ lat: 242, common_pid: 2043 } hitcount: 21
{ lat: 242, common_pid: 2036 } hitcount: 16
{ lat: 242, common_pid: 2038 } hitcount: 156
{ lat: 243, common_pid: 2037 } hitcount: 46
{ lat: 243, common_pid: 2039 } hitcount: 40
{ lat: 243, common_pid: 2042 } hitcount: 119
{ lat: 243, common_pid: 2041 } hitcount: 611
{ lat: 243, common_pid: 2036 } hitcount: 69
{ lat: 243, common_pid: 2038 } hitcount: 784
{ lat: 243, common_pid: 2040 } hitcount: 323
{ lat: 243, common_pid: 2043 } hitcount: 14
{ lat: 244, common_pid: 2043 } hitcount: 35
{ lat: 244, common_pid: 2042 } hitcount: 305
{ lat: 244, common_pid: 2039 } hitcount: 8
{ lat: 244, common_pid: 2040 } hitcount: 4515
{ lat: 244, common_pid: 2038 } hitcount: 371
{ lat: 244, common_pid: 2037 } hitcount: 31
{ lat: 244, common_pid: 2036 } hitcount: 114
{ lat: 244, common_pid: 2041 } hitcount: 3396
{ lat: 245, common_pid: 2036 } hitcount: 700
{ lat: 245, common_pid: 2041 } hitcount: 2772
{ lat: 245, common_pid: 2037 } hitcount: 268
{ lat: 245, common_pid: 2039 } hitcount: 472
{ lat: 245, common_pid: 2038 } hitcount: 2758
{ lat: 245, common_pid: 2042 } hitcount: 3833
{ lat: 245, common_pid: 2040 } hitcount: 3105
{ lat: 245, common_pid: 2043 } hitcount: 645
{ lat: 246, common_pid: 2038 } hitcount: 3451
{ lat: 246, common_pid: 2041 } hitcount: 142
{ lat: 246, common_pid: 2037 } hitcount: 5101
{ lat: 246, common_pid: 2040 } hitcount: 68
{ lat: 246, common_pid: 2043 } hitcount: 5099
{ lat: 246, common_pid: 2039 } hitcount: 5608
{ lat: 246, common_pid: 2042 } hitcount: 3723
{ lat: 246, common_pid: 2036 } hitcount: 4738
{ lat: 247, common_pid: 2042 } hitcount: 312
{ lat: 247, common_pid: 2043 } hitcount: 2385
{ lat: 247, common_pid: 2041 } hitcount: 452
{ lat: 247, common_pid: 2038 } hitcount: 792
{ lat: 247, common_pid: 2040 } hitcount: 78
{ lat: 247, common_pid: 2036 } hitcount: 2375
{ lat: 247, common_pid: 2039 } hitcount: 1834
{ lat: 247, common_pid: 2037 } hitcount: 2655
{ lat: 248, common_pid: 2037 } hitcount: 36
{ lat: 248, common_pid: 2042 } hitcount: 11
{ lat: 248, common_pid: 2038 } hitcount: 122
{ lat: 248, common_pid: 2036 } hitcount: 135
{ lat: 248, common_pid: 2039 } hitcount: 26
{ lat: 248, common_pid: 2041 } hitcount: 503
{ lat: 248, common_pid: 2043 } hitcount: 66
{ lat: 248, common_pid: 2040 } hitcount: 46
{ lat: 249, common_pid: 2037 } hitcount: 29
{ lat: 249, common_pid: 2038 } hitcount: 1
{ lat: 249, common_pid: 2043 } hitcount: 29
{ lat: 249, common_pid: 2039 } hitcount: 8
{ lat: 249, common_pid: 2042 } hitcount: 56
{ lat: 249, common_pid: 2040 } hitcount: 27
{ lat: 249, common_pid: 2041 } hitcount: 11
{ lat: 249, common_pid: 2036 } hitcount: 27
{ lat: 250, common_pid: 2038 } hitcount: 1
{ lat: 250, common_pid: 2036 } hitcount: 30
{ lat: 250, common_pid: 2040 } hitcount: 19
{ lat: 250, common_pid: 2043 } hitcount: 22
{ lat: 250, common_pid: 2042 } hitcount: 20
{ lat: 250, common_pid: 2041 } hitcount: 1
{ lat: 250, common_pid: 2039 } hitcount: 6
{ lat: 250, common_pid: 2037 } hitcount: 48
{ lat: 251, common_pid: 2037 } hitcount: 43
{ lat: 251, common_pid: 2039 } hitcount: 1
{ lat: 251, common_pid: 2036 } hitcount: 12
{ lat: 251, common_pid: 2042 } hitcount: 2
{ lat: 251, common_pid: 2041 } hitcount: 1
{ lat: 251, common_pid: 2043 } hitcount: 15
{ lat: 251, common_pid: 2040 } hitcount: 3
{ lat: 252, common_pid: 2040 } hitcount: 1
{ lat: 252, common_pid: 2036 } hitcount: 12
{ lat: 252, common_pid: 2037 } hitcount: 21
{ lat: 252, common_pid: 2043 } hitcount: 14
{ lat: 253, common_pid: 2037 } hitcount: 21
{ lat: 253, common_pid: 2039 } hitcount: 2
{ lat: 253, common_pid: 2036 } hitcount: 9
{ lat: 253, common_pid: 2043 } hitcount: 6
{ lat: 253, common_pid: 2040 } hitcount: 1
{ lat: 254, common_pid: 2036 } hitcount: 8
{ lat: 254, common_pid: 2043 } hitcount: 3
{ lat: 254, common_pid: 2041 } hitcount: 1
{ lat: 254, common_pid: 2042 } hitcount: 1
{ lat: 254, common_pid: 2039 } hitcount: 1
{ lat: 254, common_pid: 2037 } hitcount: 12
{ lat: 255, common_pid: 2043 } hitcount: 1
{ lat: 255, common_pid: 2037 } hitcount: 2
{ lat: 255, common_pid: 2036 } hitcount: 2
{ lat: 255, common_pid: 2039 } hitcount: 8
{ lat: 256, common_pid: 2043 } hitcount: 1
{ lat: 256, common_pid: 2036 } hitcount: 4
{ lat: 256, common_pid: 2039 } hitcount: 6
{ lat: 257, common_pid: 2039 } hitcount: 5
{ lat: 257, common_pid: 2036 } hitcount: 4
{ lat: 258, common_pid: 2039 } hitcount: 5
{ lat: 258, common_pid: 2036 } hitcount: 2
{ lat: 259, common_pid: 2036 } hitcount: 7
{ lat: 259, common_pid: 2039 } hitcount: 7
{ lat: 260, common_pid: 2036 } hitcount: 8
{ lat: 260, common_pid: 2039 } hitcount: 6
{ lat: 261, common_pid: 2036 } hitcount: 5
{ lat: 261, common_pid: 2039 } hitcount: 7
{ lat: 262, common_pid: 2039 } hitcount: 5
{ lat: 262, common_pid: 2036 } hitcount: 5
{ lat: 263, common_pid: 2039 } hitcount: 7
{ lat: 263, common_pid: 2036 } hitcount: 7
{ lat: 264, common_pid: 2039 } hitcount: 9
{ lat: 264, common_pid: 2036 } hitcount: 9
{ lat: 265, common_pid: 2036 } hitcount: 5
{ lat: 265, common_pid: 2039 } hitcount: 1
{ lat: 266, common_pid: 2036 } hitcount: 1
{ lat: 266, common_pid: 2039 } hitcount: 3
{ lat: 267, common_pid: 2036 } hitcount: 1
{ lat: 267, common_pid: 2039 } hitcount: 3
{ lat: 268, common_pid: 2036 } hitcount: 1
{ lat: 268, common_pid: 2039 } hitcount: 6
{ lat: 269, common_pid: 2036 } hitcount: 1
{ lat: 269, common_pid: 2043 } hitcount: 1
{ lat: 269, common_pid: 2039 } hitcount: 2
{ lat: 270, common_pid: 2040 } hitcount: 1
{ lat: 270, common_pid: 2039 } hitcount: 6
{ lat: 271, common_pid: 2041 } hitcount: 1
{ lat: 271, common_pid: 2039 } hitcount: 5
{ lat: 272, common_pid: 2039 } hitcount: 10
{ lat: 273, common_pid: 2039 } hitcount: 8
{ lat: 274, common_pid: 2039 } hitcount: 2
{ lat: 275, common_pid: 2039 } hitcount: 1
{ lat: 276, common_pid: 2039 } hitcount: 2
{ lat: 276, common_pid: 2037 } hitcount: 1
{ lat: 276, common_pid: 2038 } hitcount: 1
{ lat: 277, common_pid: 2039 } hitcount: 1
{ lat: 277, common_pid: 2042 } hitcount: 1
{ lat: 278, common_pid: 2039 } hitcount: 1
{ lat: 279, common_pid: 2039 } hitcount: 4
{ lat: 279, common_pid: 2043 } hitcount: 1
{ lat: 280, common_pid: 2039 } hitcount: 3
{ lat: 283, common_pid: 2036 } hitcount: 2
{ lat: 284, common_pid: 2039 } hitcount: 1
{ lat: 284, common_pid: 2043 } hitcount: 1
{ lat: 288, common_pid: 2039 } hitcount: 1
{ lat: 289, common_pid: 2039 } hitcount: 1
{ lat: 300, common_pid: 2039 } hitcount: 1
{ lat: 384, common_pid: 2039 } hitcount: 1
Totals:
Hits: 67625
Entries: 278
Dropped: 0
Note, the writes are around the sleep, so ideally they will all be of 250
microseconds. If you are wondering how there are several that are under
......@@ -2350,7 +2356,7 @@ will be at 200 microseconds.
But this could easily be done in userspace. To make this even more
interesting, we can mix the histogram between events that happened in the
kernel with trace_marker.
kernel with trace_marker::
# cd /sys/kernel/tracing
# echo 'latency u64 lat' > synthetic_events
......@@ -2362,177 +2368,177 @@ The difference this time is that instead of using the trace_marker to start
the latency, the sched_waking event is used, matching the common_pid for the
trace_marker write with the pid that is being woken by sched_waking.
After running cyclictest again with the same parameters, we now have:
After running cyclictest again with the same parameters, we now have::
# cat events/synthetic/latency/hist
# event histogram
#
# trigger info: hist:keys=lat,common_pid:vals=hitcount:sort=lat:size=2048 [active]
#
{ lat: 7, common_pid: 2302 } hitcount: 640
{ lat: 7, common_pid: 2299 } hitcount: 42
{ lat: 7, common_pid: 2303 } hitcount: 18
{ lat: 7, common_pid: 2305 } hitcount: 166
{ lat: 7, common_pid: 2306 } hitcount: 1
{ lat: 7, common_pid: 2301 } hitcount: 91
{ lat: 7, common_pid: 2300 } hitcount: 17
{ lat: 8, common_pid: 2303 } hitcount: 8296
{ lat: 8, common_pid: 2304 } hitcount: 6864
{ lat: 8, common_pid: 2305 } hitcount: 9464
{ lat: 8, common_pid: 2301 } hitcount: 9213
{ lat: 8, common_pid: 2306 } hitcount: 6246
{ lat: 8, common_pid: 2302 } hitcount: 8797
{ lat: 8, common_pid: 2299 } hitcount: 8771
{ lat: 8, common_pid: 2300 } hitcount: 8119
{ lat: 9, common_pid: 2305 } hitcount: 1519
{ lat: 9, common_pid: 2299 } hitcount: 2346
{ lat: 9, common_pid: 2303 } hitcount: 2841
{ lat: 9, common_pid: 2301 } hitcount: 1846
{ lat: 9, common_pid: 2304 } hitcount: 3861
{ lat: 9, common_pid: 2302 } hitcount: 1210
{ lat: 9, common_pid: 2300 } hitcount: 2762
{ lat: 9, common_pid: 2306 } hitcount: 4247
{ lat: 10, common_pid: 2299 } hitcount: 16
{ lat: 10, common_pid: 2306 } hitcount: 333
{ lat: 10, common_pid: 2303 } hitcount: 16
{ lat: 10, common_pid: 2304 } hitcount: 168
{ lat: 10, common_pid: 2302 } hitcount: 240
{ lat: 10, common_pid: 2301 } hitcount: 28
{ lat: 10, common_pid: 2300 } hitcount: 95
{ lat: 10, common_pid: 2305 } hitcount: 18
{ lat: 11, common_pid: 2303 } hitcount: 5
{ lat: 11, common_pid: 2305 } hitcount: 8
{ lat: 11, common_pid: 2306 } hitcount: 221
{ lat: 11, common_pid: 2302 } hitcount: 76
{ lat: 11, common_pid: 2304 } hitcount: 26
{ lat: 11, common_pid: 2300 } hitcount: 125
{ lat: 11, common_pid: 2299 } hitcount: 2
{ lat: 12, common_pid: 2305 } hitcount: 3
{ lat: 12, common_pid: 2300 } hitcount: 6
{ lat: 12, common_pid: 2306 } hitcount: 90
{ lat: 12, common_pid: 2302 } hitcount: 4
{ lat: 12, common_pid: 2303 } hitcount: 1
{ lat: 12, common_pid: 2304 } hitcount: 122
{ lat: 13, common_pid: 2300 } hitcount: 12
{ lat: 13, common_pid: 2301 } hitcount: 1
{ lat: 13, common_pid: 2306 } hitcount: 32
{ lat: 13, common_pid: 2302 } hitcount: 5
{ lat: 13, common_pid: 2305 } hitcount: 1
{ lat: 13, common_pid: 2303 } hitcount: 1
{ lat: 13, common_pid: 2304 } hitcount: 61
{ lat: 14, common_pid: 2303 } hitcount: 4
{ lat: 14, common_pid: 2306 } hitcount: 5
{ lat: 14, common_pid: 2305 } hitcount: 4
{ lat: 14, common_pid: 2304 } hitcount: 62
{ lat: 14, common_pid: 2302 } hitcount: 19
{ lat: 14, common_pid: 2300 } hitcount: 33
{ lat: 14, common_pid: 2299 } hitcount: 1
{ lat: 14, common_pid: 2301 } hitcount: 4
{ lat: 15, common_pid: 2305 } hitcount: 1
{ lat: 15, common_pid: 2302 } hitcount: 25
{ lat: 15, common_pid: 2300 } hitcount: 11
{ lat: 15, common_pid: 2299 } hitcount: 5
{ lat: 15, common_pid: 2301 } hitcount: 1
{ lat: 15, common_pid: 2304 } hitcount: 8
{ lat: 15, common_pid: 2303 } hitcount: 1
{ lat: 15, common_pid: 2306 } hitcount: 6
{ lat: 16, common_pid: 2302 } hitcount: 31
{ lat: 16, common_pid: 2306 } hitcount: 3
{ lat: 16, common_pid: 2300 } hitcount: 5
{ lat: 17, common_pid: 2302 } hitcount: 6
{ lat: 17, common_pid: 2303 } hitcount: 1
{ lat: 18, common_pid: 2304 } hitcount: 1
{ lat: 18, common_pid: 2302 } hitcount: 8
{ lat: 18, common_pid: 2299 } hitcount: 1
{ lat: 18, common_pid: 2301 } hitcount: 1
{ lat: 19, common_pid: 2303 } hitcount: 4
{ lat: 19, common_pid: 2304 } hitcount: 5
{ lat: 19, common_pid: 2302 } hitcount: 4
{ lat: 19, common_pid: 2299 } hitcount: 3
{ lat: 19, common_pid: 2306 } hitcount: 1
{ lat: 19, common_pid: 2300 } hitcount: 4
{ lat: 19, common_pid: 2305 } hitcount: 5
{ lat: 20, common_pid: 2299 } hitcount: 2
{ lat: 20, common_pid: 2302 } hitcount: 3
{ lat: 20, common_pid: 2305 } hitcount: 1
{ lat: 20, common_pid: 2300 } hitcount: 2
{ lat: 20, common_pid: 2301 } hitcount: 2
{ lat: 20, common_pid: 2303 } hitcount: 3
{ lat: 21, common_pid: 2305 } hitcount: 1
{ lat: 21, common_pid: 2299 } hitcount: 5
{ lat: 21, common_pid: 2303 } hitcount: 4
{ lat: 21, common_pid: 2302 } hitcount: 7
{ lat: 21, common_pid: 2300 } hitcount: 1
{ lat: 21, common_pid: 2301 } hitcount: 5
{ lat: 21, common_pid: 2304 } hitcount: 2
{ lat: 22, common_pid: 2302 } hitcount: 5
{ lat: 22, common_pid: 2303 } hitcount: 1
{ lat: 22, common_pid: 2306 } hitcount: 3
{ lat: 22, common_pid: 2301 } hitcount: 2
{ lat: 22, common_pid: 2300 } hitcount: 1
{ lat: 22, common_pid: 2299 } hitcount: 1
{ lat: 22, common_pid: 2305 } hitcount: 1
{ lat: 22, common_pid: 2304 } hitcount: 1
{ lat: 23, common_pid: 2299 } hitcount: 1
{ lat: 23, common_pid: 2306 } hitcount: 2
{ lat: 23, common_pid: 2302 } hitcount: 6
{ lat: 24, common_pid: 2302 } hitcount: 3
{ lat: 24, common_pid: 2300 } hitcount: 1
{ lat: 24, common_pid: 2306 } hitcount: 2
{ lat: 24, common_pid: 2305 } hitcount: 1
{ lat: 24, common_pid: 2299 } hitcount: 1
{ lat: 25, common_pid: 2300 } hitcount: 1
{ lat: 25, common_pid: 2302 } hitcount: 4
{ lat: 26, common_pid: 2302 } hitcount: 2
{ lat: 27, common_pid: 2305 } hitcount: 1
{ lat: 27, common_pid: 2300 } hitcount: 1
{ lat: 27, common_pid: 2302 } hitcount: 3
{ lat: 28, common_pid: 2306 } hitcount: 1
{ lat: 28, common_pid: 2302 } hitcount: 4
{ lat: 29, common_pid: 2302 } hitcount: 1
{ lat: 29, common_pid: 2300 } hitcount: 2
{ lat: 29, common_pid: 2306 } hitcount: 1
{ lat: 29, common_pid: 2304 } hitcount: 1
{ lat: 30, common_pid: 2302 } hitcount: 4
{ lat: 31, common_pid: 2302 } hitcount: 6
{ lat: 32, common_pid: 2302 } hitcount: 1
{ lat: 33, common_pid: 2299 } hitcount: 1
{ lat: 33, common_pid: 2302 } hitcount: 3
{ lat: 34, common_pid: 2302 } hitcount: 2
{ lat: 35, common_pid: 2302 } hitcount: 1
{ lat: 35, common_pid: 2304 } hitcount: 1
{ lat: 36, common_pid: 2302 } hitcount: 4
{ lat: 37, common_pid: 2302 } hitcount: 6
{ lat: 38, common_pid: 2302 } hitcount: 2
{ lat: 39, common_pid: 2302 } hitcount: 2
{ lat: 39, common_pid: 2304 } hitcount: 1
{ lat: 40, common_pid: 2304 } hitcount: 2
{ lat: 40, common_pid: 2302 } hitcount: 5
{ lat: 41, common_pid: 2304 } hitcount: 1
{ lat: 41, common_pid: 2302 } hitcount: 8
{ lat: 42, common_pid: 2302 } hitcount: 6
{ lat: 42, common_pid: 2304 } hitcount: 1
{ lat: 43, common_pid: 2302 } hitcount: 3
{ lat: 43, common_pid: 2304 } hitcount: 4
{ lat: 44, common_pid: 2302 } hitcount: 6
{ lat: 45, common_pid: 2302 } hitcount: 5
{ lat: 46, common_pid: 2302 } hitcount: 5
{ lat: 47, common_pid: 2302 } hitcount: 7
{ lat: 48, common_pid: 2301 } hitcount: 1
{ lat: 48, common_pid: 2302 } hitcount: 9
{ lat: 49, common_pid: 2302 } hitcount: 3
{ lat: 50, common_pid: 2302 } hitcount: 1
{ lat: 50, common_pid: 2301 } hitcount: 1
{ lat: 51, common_pid: 2302 } hitcount: 2
{ lat: 51, common_pid: 2301 } hitcount: 1
{ lat: 61, common_pid: 2302 } hitcount: 1
{ lat: 110, common_pid: 2302 } hitcount: 1
Totals:
Hits: 89565
Entries: 158
Dropped: 0
# event histogram
#
# trigger info: hist:keys=lat,common_pid:vals=hitcount:sort=lat:size=2048 [active]
#
{ lat: 7, common_pid: 2302 } hitcount: 640
{ lat: 7, common_pid: 2299 } hitcount: 42
{ lat: 7, common_pid: 2303 } hitcount: 18
{ lat: 7, common_pid: 2305 } hitcount: 166
{ lat: 7, common_pid: 2306 } hitcount: 1
{ lat: 7, common_pid: 2301 } hitcount: 91
{ lat: 7, common_pid: 2300 } hitcount: 17
{ lat: 8, common_pid: 2303 } hitcount: 8296
{ lat: 8, common_pid: 2304 } hitcount: 6864
{ lat: 8, common_pid: 2305 } hitcount: 9464
{ lat: 8, common_pid: 2301 } hitcount: 9213
{ lat: 8, common_pid: 2306 } hitcount: 6246
{ lat: 8, common_pid: 2302 } hitcount: 8797
{ lat: 8, common_pid: 2299 } hitcount: 8771
{ lat: 8, common_pid: 2300 } hitcount: 8119
{ lat: 9, common_pid: 2305 } hitcount: 1519
{ lat: 9, common_pid: 2299 } hitcount: 2346
{ lat: 9, common_pid: 2303 } hitcount: 2841
{ lat: 9, common_pid: 2301 } hitcount: 1846
{ lat: 9, common_pid: 2304 } hitcount: 3861
{ lat: 9, common_pid: 2302 } hitcount: 1210
{ lat: 9, common_pid: 2300 } hitcount: 2762
{ lat: 9, common_pid: 2306 } hitcount: 4247
{ lat: 10, common_pid: 2299 } hitcount: 16
{ lat: 10, common_pid: 2306 } hitcount: 333
{ lat: 10, common_pid: 2303 } hitcount: 16
{ lat: 10, common_pid: 2304 } hitcount: 168
{ lat: 10, common_pid: 2302 } hitcount: 240
{ lat: 10, common_pid: 2301 } hitcount: 28
{ lat: 10, common_pid: 2300 } hitcount: 95
{ lat: 10, common_pid: 2305 } hitcount: 18
{ lat: 11, common_pid: 2303 } hitcount: 5
{ lat: 11, common_pid: 2305 } hitcount: 8
{ lat: 11, common_pid: 2306 } hitcount: 221
{ lat: 11, common_pid: 2302 } hitcount: 76
{ lat: 11, common_pid: 2304 } hitcount: 26
{ lat: 11, common_pid: 2300 } hitcount: 125
{ lat: 11, common_pid: 2299 } hitcount: 2
{ lat: 12, common_pid: 2305 } hitcount: 3
{ lat: 12, common_pid: 2300 } hitcount: 6
{ lat: 12, common_pid: 2306 } hitcount: 90
{ lat: 12, common_pid: 2302 } hitcount: 4
{ lat: 12, common_pid: 2303 } hitcount: 1
{ lat: 12, common_pid: 2304 } hitcount: 122
{ lat: 13, common_pid: 2300 } hitcount: 12
{ lat: 13, common_pid: 2301 } hitcount: 1
{ lat: 13, common_pid: 2306 } hitcount: 32
{ lat: 13, common_pid: 2302 } hitcount: 5
{ lat: 13, common_pid: 2305 } hitcount: 1
{ lat: 13, common_pid: 2303 } hitcount: 1
{ lat: 13, common_pid: 2304 } hitcount: 61
{ lat: 14, common_pid: 2303 } hitcount: 4
{ lat: 14, common_pid: 2306 } hitcount: 5
{ lat: 14, common_pid: 2305 } hitcount: 4
{ lat: 14, common_pid: 2304 } hitcount: 62
{ lat: 14, common_pid: 2302 } hitcount: 19
{ lat: 14, common_pid: 2300 } hitcount: 33
{ lat: 14, common_pid: 2299 } hitcount: 1
{ lat: 14, common_pid: 2301 } hitcount: 4
{ lat: 15, common_pid: 2305 } hitcount: 1
{ lat: 15, common_pid: 2302 } hitcount: 25
{ lat: 15, common_pid: 2300 } hitcount: 11
{ lat: 15, common_pid: 2299 } hitcount: 5
{ lat: 15, common_pid: 2301 } hitcount: 1
{ lat: 15, common_pid: 2304 } hitcount: 8
{ lat: 15, common_pid: 2303 } hitcount: 1
{ lat: 15, common_pid: 2306 } hitcount: 6
{ lat: 16, common_pid: 2302 } hitcount: 31
{ lat: 16, common_pid: 2306 } hitcount: 3
{ lat: 16, common_pid: 2300 } hitcount: 5
{ lat: 17, common_pid: 2302 } hitcount: 6
{ lat: 17, common_pid: 2303 } hitcount: 1
{ lat: 18, common_pid: 2304 } hitcount: 1
{ lat: 18, common_pid: 2302 } hitcount: 8
{ lat: 18, common_pid: 2299 } hitcount: 1
{ lat: 18, common_pid: 2301 } hitcount: 1
{ lat: 19, common_pid: 2303 } hitcount: 4
{ lat: 19, common_pid: 2304 } hitcount: 5
{ lat: 19, common_pid: 2302 } hitcount: 4
{ lat: 19, common_pid: 2299 } hitcount: 3
{ lat: 19, common_pid: 2306 } hitcount: 1
{ lat: 19, common_pid: 2300 } hitcount: 4
{ lat: 19, common_pid: 2305 } hitcount: 5
{ lat: 20, common_pid: 2299 } hitcount: 2
{ lat: 20, common_pid: 2302 } hitcount: 3
{ lat: 20, common_pid: 2305 } hitcount: 1
{ lat: 20, common_pid: 2300 } hitcount: 2
{ lat: 20, common_pid: 2301 } hitcount: 2
{ lat: 20, common_pid: 2303 } hitcount: 3
{ lat: 21, common_pid: 2305 } hitcount: 1
{ lat: 21, common_pid: 2299 } hitcount: 5
{ lat: 21, common_pid: 2303 } hitcount: 4
{ lat: 21, common_pid: 2302 } hitcount: 7
{ lat: 21, common_pid: 2300 } hitcount: 1
{ lat: 21, common_pid: 2301 } hitcount: 5
{ lat: 21, common_pid: 2304 } hitcount: 2
{ lat: 22, common_pid: 2302 } hitcount: 5
{ lat: 22, common_pid: 2303 } hitcount: 1
{ lat: 22, common_pid: 2306 } hitcount: 3
{ lat: 22, common_pid: 2301 } hitcount: 2
{ lat: 22, common_pid: 2300 } hitcount: 1
{ lat: 22, common_pid: 2299 } hitcount: 1
{ lat: 22, common_pid: 2305 } hitcount: 1
{ lat: 22, common_pid: 2304 } hitcount: 1
{ lat: 23, common_pid: 2299 } hitcount: 1
{ lat: 23, common_pid: 2306 } hitcount: 2
{ lat: 23, common_pid: 2302 } hitcount: 6
{ lat: 24, common_pid: 2302 } hitcount: 3
{ lat: 24, common_pid: 2300 } hitcount: 1
{ lat: 24, common_pid: 2306 } hitcount: 2
{ lat: 24, common_pid: 2305 } hitcount: 1
{ lat: 24, common_pid: 2299 } hitcount: 1
{ lat: 25, common_pid: 2300 } hitcount: 1
{ lat: 25, common_pid: 2302 } hitcount: 4
{ lat: 26, common_pid: 2302 } hitcount: 2
{ lat: 27, common_pid: 2305 } hitcount: 1
{ lat: 27, common_pid: 2300 } hitcount: 1
{ lat: 27, common_pid: 2302 } hitcount: 3
{ lat: 28, common_pid: 2306 } hitcount: 1
{ lat: 28, common_pid: 2302 } hitcount: 4
{ lat: 29, common_pid: 2302 } hitcount: 1
{ lat: 29, common_pid: 2300 } hitcount: 2
{ lat: 29, common_pid: 2306 } hitcount: 1
{ lat: 29, common_pid: 2304 } hitcount: 1
{ lat: 30, common_pid: 2302 } hitcount: 4
{ lat: 31, common_pid: 2302 } hitcount: 6
{ lat: 32, common_pid: 2302 } hitcount: 1
{ lat: 33, common_pid: 2299 } hitcount: 1
{ lat: 33, common_pid: 2302 } hitcount: 3
{ lat: 34, common_pid: 2302 } hitcount: 2
{ lat: 35, common_pid: 2302 } hitcount: 1
{ lat: 35, common_pid: 2304 } hitcount: 1
{ lat: 36, common_pid: 2302 } hitcount: 4
{ lat: 37, common_pid: 2302 } hitcount: 6
{ lat: 38, common_pid: 2302 } hitcount: 2
{ lat: 39, common_pid: 2302 } hitcount: 2
{ lat: 39, common_pid: 2304 } hitcount: 1
{ lat: 40, common_pid: 2304 } hitcount: 2
{ lat: 40, common_pid: 2302 } hitcount: 5
{ lat: 41, common_pid: 2304 } hitcount: 1
{ lat: 41, common_pid: 2302 } hitcount: 8
{ lat: 42, common_pid: 2302 } hitcount: 6
{ lat: 42, common_pid: 2304 } hitcount: 1
{ lat: 43, common_pid: 2302 } hitcount: 3
{ lat: 43, common_pid: 2304 } hitcount: 4
{ lat: 44, common_pid: 2302 } hitcount: 6
{ lat: 45, common_pid: 2302 } hitcount: 5
{ lat: 46, common_pid: 2302 } hitcount: 5
{ lat: 47, common_pid: 2302 } hitcount: 7
{ lat: 48, common_pid: 2301 } hitcount: 1
{ lat: 48, common_pid: 2302 } hitcount: 9
{ lat: 49, common_pid: 2302 } hitcount: 3
{ lat: 50, common_pid: 2302 } hitcount: 1
{ lat: 50, common_pid: 2301 } hitcount: 1
{ lat: 51, common_pid: 2302 } hitcount: 2
{ lat: 51, common_pid: 2301 } hitcount: 1
{ lat: 61, common_pid: 2302 } hitcount: 1
{ lat: 110, common_pid: 2302 } hitcount: 1
Totals:
Hits: 89565
Entries: 158
Dropped: 0
This doesn't tell us any information about how late cyclictest may have
woken up, but it does show us a nice histogram of how long it took from
......
Documentation/trace/index.rst
View file @ ea272257
......@@ -18,6 +18,7 @@ Linux Tracing Technologies
events-nmi
events-msr
mmiotrace
histogram
hwlat_detector
intel_th
stm
kernel/trace/Kconfig
View file @ ea272257
......@@ -605,7 +605,7 @@ config HIST_TRIGGERS
Inter-event tracing of quantities such as latencies is also
supported using hist triggers under this option.
See Documentation/trace/histogram.txt.
See Documentation/trace/histogram.rst.
If in doubt, say N.
config MMIOTRACE_TEST
......
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