Re: [PATCH 1/2] ftrace: Add task_comm support for trace_event

From: Steven Rostedt
Date: Thu May 21 2009 - 09:16:01 EST



On Thu, 21 May 2009, Zhaolei wrote:

> If we use trace_event alone(without function trace, .etc),
> it can't output enough task command information.
>
> Before patch:
> # echo 1 > debugfs/tracing/events/sched/sched_switch/enable
> # cat debugfs/tracing/trace
> # tracer: nop
> #
> # TASK-PID CPU# TIMESTAMP FUNCTION
> # | | | | |
> <...>-2289 [000] 526276.724790: sched_switch: task bash:2289 [120] ==> sshd:2287 [120]
> <...>-2287 [000] 526276.725231: sched_switch: task sshd:2287 [120] ==> bash:2289 [120]
> <...>-2289 [000] 526276.725452: sched_switch: task bash:2289 [120] ==> sshd:2287 [120]
> <...>-2287 [000] 526276.727181: sched_switch: task sshd:2287 [120] ==> swapper:0 [140]
> <idle>-0 [000] 526277.032734: sched_switch: task swapper:0 [140] ==> events/0:5 [115]
> <...>-5 [000] 526277.032782: sched_switch: task events/0:5 [115] ==> swapper:0 [140]
> ...
>
> After patch:
> # tracer: nop
> #
> # TASK-PID CPU# TIMESTAMP FUNCTION
> # | | | | |
> bash-2269 [000] 527347.989229: sched_switch: task bash:2269 [120] ==> sshd:2267 [120]
> sshd-2267 [000] 527347.990960: sched_switch: task sshd:2267 [120] ==> bash:2269 [120]
> bash-2269 [000] 527347.991143: sched_switch: task bash:2269 [120] ==> sshd:2267 [120]
> sshd-2267 [000] 527347.992959: sched_switch: task sshd:2267 [120] ==> swapper:0 [140]
> <idle>-0 [000] 527348.531989: sched_switch: task swapper:0 [140] ==> events/0:5 [115]
> events/0-5 [000] 527348.532115: sched_switch: task events/0:5 [115] ==> swapper:0 [140]

Heh, this was on my todo list today. Thanks, I'll suck up this patch, if
Ingo doesn't get to it first. If he does.

Acked-by: Steven Rostedt <rostedt@xxxxxxxxxxx>

-- Steve
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