Re: [PATCH v4 00/11] tracing: common error_log for ftrace

[Masami Hiramatsu]

Hi Tom,

On Fri, 22 Mar 2019 10:34:26 -0500
Tom Zanussi <zanussi@xxxxxxxxxx> wrote:

> From: Tom Zanussi <tom.zanussi@xxxxxxxxxxxxxxx>
> 
> Hi,
> 
> This is v4 of the frace error_log patchset.  This version adds
> Masami's probe events error_log patches and removes the previous
> placeholder for that.  It also removes the hist trigger extended error
> err testcase and replaces it with a basic error_log functionality
> testcase, and replaces the error numbering with timestamps, also as
> suggested by Masami.  Finally, the Documentation and README are both
> updated to describe the error_log.

Thank you for updating this series! :)

> 
> Note: The probe event error_log test cases failed on my Ubuntu system,
> due to the >& redirection operator that dash doesn't understand, so I
> tacked on a final patch that fixes it for me.  If acceptable, feel
> free to just merge it with Masami's patch.

Oops, that's my laziness... that should be > /dev/null 2>&1, sorry.

[...]
> Below is an example session of a few failed commands and the
> corresponding error_log contents:
> 
>   # echo > /sys/kernel/debug/tracing/error_log
> 
>   # echo 'hist:keys=pid:ts0=common_timestamp.usecs if comm=="cyclictest"' >> /sys/kernel/debug/tracing/events/sched/sched_wakeup/trigger
>   # echo 'hist:keys=pid:ts0=common_timestamp.usecs if comm=="cyclictest"' >> /sys/kernel/debug/tracing/events/sched/sched_wakeup/trigger
>   -su: echo: write error: Invalid argument
> 
>   #  cat /sys/kernel/debug/tracing/error_log
>   [  217.431858] hist:sched:sched_wakeup: error: Variable already defined
>     Command: keys=pid:ts0=common_timestamp.usecs if comm=="cyclictest"
>                       ^
> 

Yeah, this looks good to me :)

Thank you!

-- 
Masami Hiramatsu <mhiramat@xxxxxxxxxx>