Commit ed90a446 authored by Cody P Schafer's avatar Cody P Schafer Committed by Arnaldo Carvalho de Melo

perf Documentation: sysfs events/ interfaces

Add documentation for the <event>, <event>.scale, and <event>.unit
files in sysfs.

	<event>.scale and <event>.unit were undocumented.
	<event> was previously documented only for specific powerpc pmu events.
Signed-off-by: default avatarCody P Schafer <dev@codyps.com>
Signed-off-by: default avatarSukadev Bhattiprolu <sukadev@linux.vnet.ibm.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Anshuman Khandual <khandual@linux.vnet.ibm.com>
Cc: Cody P Schafer <dev@codyps.com>
Cc: Haren Myneni <hbabu@us.ibm.com>
Cc: Haren Myneni <hbabu@us.ibm.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Michael Ellerman <michaele@au1.ibm.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: linuxppc-dev@lists.ozlabs.org
Link: http://lkml.kernel.org/r/1412143402-26061-4-git-send-email-sukadev@linux.vnet.ibm.comSigned-off-by: default avatarArnaldo Carvalho de Melo <acme@redhat.com>
parent 1e378ebd
......@@ -599,3 +599,63 @@ Description: POWER-systems specific performance monitoring events
Further, multiple terms like 'event=0xNNNN' can be specified
and separated with comma. All available terms are defined in
the /sys/bus/event_source/devices/<dev>/format file.
What: /sys/bus/event_source/devices/<pmu>/events/<event>
Date: 2014/02/24
Contact: Linux kernel mailing list <linux-kernel@vger.kernel.org>
Description: Per-pmu performance monitoring events specific to the running system
Each file (except for some of those with a '.' in them, '.unit'
and '.scale') in the 'events' directory describes a single
performance monitoring event supported by the <pmu>. The name
of the file is the name of the event.
File contents:
<term>[=<value>][,<term>[=<value>]]...
Where <term> is one of the terms listed under
/sys/bus/event_source/devices/<pmu>/format/ and <value> is
a number is base-16 format with a '0x' prefix (lowercase only).
If a <term> is specified alone (without an assigned value), it
is implied that 0x1 is assigned to that <term>.
Examples (each of these lines would be in a seperate file):
event=0x2abc
event=0x423,inv,cmask=0x3
domain=0x1,offset=0x8,starting_index=0xffff
Each of the assignments indicates a value to be assigned to a
particular set of bits (as defined by the format file
corresponding to the <term>) in the perf_event structure passed
to the perf_open syscall.
What: /sys/bus/event_source/devices/<pmu>/events/<event>.unit
Date: 2014/02/24
Contact: Linux kernel mailing list <linux-kernel@vger.kernel.org>
Description: Perf event units
A string specifying the English plural numerical unit that <event>
(once multiplied by <event>.scale) represents.
Example:
Joules
What: /sys/bus/event_source/devices/<pmu>/events/<event>.scale
Date: 2014/02/24
Contact: Linux kernel mailing list <linux-kernel@vger.kernel.org>
Description: Perf event scaling factors
A string representing a floating point value expressed in
scientific notation to be multiplied by the event count
recieved from the kernel to match the unit specified in the
<event>.unit file.
Example:
2.3283064365386962890625e-10
This is provided to avoid performing floating point arithmetic
in the kernel.
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