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  1. 10 Mar, 2009 10 commits
    • KOSAKI Motohiro's avatar
      doc: add trace_buf_size description to kernel-parameters.txt · 631595fb
      KOSAKI Motohiro authored 
      from early boot tracing view, trace_buf_size parameter is important.
it should be documented.
Signed-off-by: default avatarKOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
LKML-Reference: <20090310135200.A48B.A69D9226@jp.fujitsu.com>
Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
      631595fb
    • Ingo Molnar's avatar
      Merge branch 'tip/tracing/ftrace' of... · 9a1043d1
      Ingo Molnar authored 
      Merge branch 'tip/tracing/ftrace' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-2.6-trace into tracing/ftrace
      9a1043d1
    • Ingo Molnar's avatar
      Merge branches 'tracing/doc', 'tracing/ftrace', 'tracing/printk' and 'linus' into tracing/core · 12e87e36
      Ingo Molnar authored
      12e87e36
    • Steven Rostedt's avatar
      tracing: remove obsolete TRACE_EVENT_FORMAT macro · 157587d7
      Steven Rostedt authored 
      Impact: clean up

The TRACE_EVENT_FORMAT macro is no longer used by trace points
and only the DECLARE_TRACE, TRACE_FORMAT or TRACE_EVENT macros should
be used by them. Although the TRACE_EVENT_FORMAT macro is still used
by the internal tracing utility, it should not be used in core
kernel code.
Signed-off-by: default avatarSteven Rostedt <srostedt@redhat.com>
      157587d7
    • Steven Rostedt's avatar
      tracing: convert irq trace points to new macros · d6e2ca4c
      Steven Rostedt authored 
      Impact: enhancement

Converted the two irq trace point macros. The entry macro copies
the name of the irq handler, thus it is better to simply use the
TRACE_FORMAT macro which uses the trace_printk.

The return of the handler does not need to record the name, thus
the faster C style handler is more approriate.
Signed-off-by: default avatarSteven Rostedt <srostedt@redhat.com>
      d6e2ca4c
    • Steven Rostedt's avatar
      tracing: convert the sched trace points to the TRACE_EVENT macros · 12b5fdb8
      Steven Rostedt authored 
      Impact: enhancement

This patch converts the rest of the sched trace points to use the new
more powerful TRACE_EVENT macro.
Signed-off-by: default avatarSteven Rostedt <srostedt@redhat.com>
      12b5fdb8
    • Steven Rostedt's avatar
      tracing: new format for specialized trace points · da4d0302
      Steven Rostedt authored 
      Impact: clean up and enhancement

The TRACE_EVENT_FORMAT macro looks quite ugly and is limited in its
ability to save data as well as to print the record out. Working with
Ingo Molnar, we came up with a new format that is much more pleasing to
the eye of C developers. This new macro is more C style than the old
macro, and is more obvious to what it does.

Here's the example. The only updated macro in this patch is the
sched_switch trace point.

The old method looked like this:

 TRACE_EVENT_FORMAT(sched_switch,
        TP_PROTO(struct rq *rq, struct task_struct *prev,
                struct task_struct *next),
        TP_ARGS(rq, prev, next),
        TP_FMT("task %s:%d ==> %s:%d",
              prev->comm, prev->pid, next->comm, next->pid),
        TRACE_STRUCT(
                TRACE_FIELD(pid_t, prev_pid, prev->pid)
                TRACE_FIELD(int, prev_prio, prev->prio)
                TRACE_FIELD_SPECIAL(char next_comm[TASK_COMM_LEN],
                                    next_comm,
                                    TP_CMD(memcpy(TRACE_ENTRY->next_comm,
                                                 next->comm,
                                                 TASK_COMM_LEN)))
                TRACE_FIELD(pid_t, next_pid, next->pid)
                TRACE_FIELD(int, next_prio, next->prio)
        ),
        TP_RAW_FMT("prev %d:%d ==> next %s:%d:%d")
        );

The above method is hard to read and requires two format fields.

The new method:

 /*
  * Tracepoint for task switches, performed by the scheduler:
  *
  * (NOTE: the 'rq' argument is not used by generic trace events,
  *        but used by the latency tracer plugin. )
  */
 TRACE_EVENT(sched_switch,

	TP_PROTO(struct rq *rq, struct task_struct *prev,
		 struct task_struct *next),

	TP_ARGS(rq, prev, next),

	TP_STRUCT__entry(
		__array(	char,	prev_comm,	TASK_COMM_LEN	)
		__field(	pid_t,	prev_pid			)
		__field(	int,	prev_prio			)
		__array(	char,	next_comm,	TASK_COMM_LEN	)
		__field(	pid_t,	next_pid			)
		__field(	int,	next_prio			)
	),

	TP_printk("task %s:%d [%d] ==> %s:%d [%d]",
		__entry->prev_comm, __entry->prev_pid, __entry->prev_prio,
		__entry->next_comm, __entry->next_pid, __entry->next_prio),

	TP_fast_assign(
		memcpy(__entry->next_comm, next->comm, TASK_COMM_LEN);
		__entry->prev_pid	= prev->pid;
		__entry->prev_prio	= prev->prio;
		memcpy(__entry->prev_comm, prev->comm, TASK_COMM_LEN);
		__entry->next_pid	= next->pid;
		__entry->next_prio	= next->prio;
	)
 );

This macro is called TRACE_EVENT, it is broken up into 5 parts:

 TP_PROTO:        the proto type of the trace point
 TP_ARGS:         the arguments of the trace point
 TP_STRUCT_entry: the structure layout of the entry in the ring buffer
 TP_printk:       the printk format
 TP_fast_assign:  the method used to write the entry into the ring buffer

The structure is the definition of how the event will be saved in the
ring buffer. The printk is used by the internal tracing in case of
an oops, and the kernel needs to print out the format of the record
to the console. This the TP_printk gives a means to show the records
in a human readable format. It is also used to print out the data
from the trace file.

The TP_fast_assign is executed directly. It is basically like a C function,
where the __entry is the handle to the record.
Signed-off-by: default avatarSteven Rostedt <srostedt@redhat.com>
      da4d0302
    • Steven Rostedt's avatar
      tracing: use generic __stringify · 9cc26a26
      Steven Rostedt authored 
      Impact: clean up

This removes the custom made STR(x) macros in the tracer and uses
the generic __stringify macro instead.
Signed-off-by: default avatarSteven Rostedt <srostedt@redhat.com>
      9cc26a26
    • Steven Rostedt's avatar
      tracing: replace TP<var> with TP_<var> · 2939b046
      Steven Rostedt authored 
      Impact: clean up

The macros TPPROTO, TPARGS, TPFMT, TPRAWFMT, and TPCMD all look a bit
ugly. This patch adds an underscore to their names.
Signed-off-by: default avatarSteven Rostedt <srostedt@redhat.com>
      2939b046
    • Steven Rostedt's avatar
      tracing: typecast sizeof and offsetof to unsigned int · 156b5f17
      Steven Rostedt authored 
      Impact: fix compiler warnings

On x86_64 sizeof and offsetof are treated as long, where as on x86_32
they are int. This patch typecasts them to unsigned int to avoid
one arch giving warnings while the other does not.
Reported-by: default avatarIngo Molnar <mingo@elte.hu>
Signed-off-by: default avatarSteven Rostedt <srostedt@redhat.com>
      156b5f17
  3. 09 Mar, 2009 3 commits
    • KOSAKI Motohiro's avatar
      tracing: Don't use tracing_record_cmdline() in workqueue tracer · c3ffc7a4
      KOSAKI Motohiro authored 
      Impact: improve workqueue tracer output

Currently, /sys/kernel/debug/tracing/trace_stat/workqueues can display
wrong and strange thread names.

Why?

Currently, ftrace has tracing_record_cmdline()/trace_find_cmdline()
convenience function that implements a task->comm string cache.

This can avoid unnecessary memcpy overhead and the workqueue tracer
uses it.

However, in general, any trace statistics feature shouldn't use
tracing_record_cmdline() because trace statistics can display
very old process. Then comm cache can return wrong string because
recent process overrides the cache.

Fortunately, workqueue trace guarantees that displayed processes
are live. Thus we can search comm string from PID at display time.

<before>

% cat workqueues
 # CPU  INSERTED  EXECUTED   NAME
 # |      |         |          |

   7 431913     431913       kondemand/7
   7      0          0       tail
   7     21         21       git
   7      0          0       ls
   7      9          9       cat
   7 832632     832632       unix_chkpwd
   7 236292     236292       ls

Note: tail, git, ls, cat unix_chkpwd are obiously not workqueue thread.

<after>

% cat workqueues
 # CPU  INSERTED  EXECUTED   NAME
 # |      |         |          |

   7    510        510       kondemand/7
   7      0          0       kmpathd/7
   7     15         15       ata/7
   7      0          0       aio/7
   7     11         11       kblockd/7
   7   1063       1063       work_on_cpu/7
   7    167        167       events/7
Signed-off-by: default avatarKOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Lai Jiangshan <laijs@cn.fujitsu.com>
Cc: Steven Rostedt <srostedt@redhat.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
      c3ffc7a4
    • Ingo Molnar's avatar
      tracing: optimize trace_printk() · 7bffc23e
      Ingo Molnar authored 
      Impact: micro-optimization

trace_printk() does this unconditionally:

	trace_printk_fmt = fmt;

Where trace_printk_fmt is an entry into a global array. This is
very SMP-unfriendly.

So only write it once per bootup.

Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Peter Zijlstra <peterz@infradead.org>
LKML-Reference: <1236356510-8381-5-git-send-email-fweisbec@gmail.com>
Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
      7bffc23e
    • Ingo Molnar's avatar
      tracing: trace_printk() fix, move format array to data section · 8a20d84d
      Ingo Molnar authored 
      Impact: fix kernel crash when using trace_printk()

trace_printk_fmt section is defined into the readonly section.
But we do:

	trace_printk_fmt = fmt;

to fill in that table of format strings - which is not read-only.
Under CONFIG_DEBUG_RODATA=y this crashes ...

Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Peter Zijlstra <peterz@infradead.org>
LKML-Reference: <1236356510-8381-5-git-send-email-fweisbec@gmail.com>
Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
      8a20d84d
  5. 08 Mar, 2009 21 commits
  7. 06 Mar, 2009 6 commits
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