Re: [PATCH] Update old Mini-HOWTO for ftrace

From: GeunSik Lim
Date: Tue Apr 07 2009 - 01:08:23 EST


Dear steven,

I confirm http://lkml.org/lkml/2009/3/23/24 webpage now.
I am gratified with a similar patch that another people sent this problem.

In fact, I figured out trivial problem of old mini-HOWTO according to
http://www.redhat.com/docs/en-US/Red_Hat_Enterprise_MRG/1.1/html/Realtime_Tuning_Guide/sect-Realtime_Tuning_Guide-Realtime_Specific_Tuning-Using_the_ftrace_Utility_for_Tracing_Latencies.html
web manual.

I want you to change MRG Kernel from ftrace to function for
consistency in private.
Thank you for interesting article

Regards,
GeunSik Lim..

2009/4/7 Steven Rostedt <srostedt@xxxxxxxxxx>:
>
> On Mon, 2009-04-06 at 23:02 +0900, GeunSik Lim wrote:
>> Dear Steven,
>>
>> Â ÂThe author of ftrace(Internal kernel Function Tracer) feature
>> renamed the ftrace tracer
>> Â Â to function to avoid further confusion between the ftrace
>> infrastructure and the
>> Â Â function tracer on Oct-20, 2008.
>>
>> Â Â But, Update of Mini-HOWTO document are still not working
>> Â Â .
>> Â Â Most of the developers often utilize "/debug/tracing/README" file
>> as Mini-HOWTO.
>> Â Â They will confuse definition and usage about ftrace Âbetween
>> README(ftrace) file
>> Â Â and available_tracers(function) file after linux-2.6.27 like me.
>> Â Â And, I want you to append "chrt -f 5 sleep 1" command as simple
>> example for latency.
>>
>> Â Â Signed-off-by: GeunSik Lim <leemgs1@xxxxxxxxx>
>> Â Â Signed-off-by: Steven Rostedt <srostedt@xxxxxxxxxx>
>> Â Â Signed-off-by: Ingo Molnar <mingo@xxxxxxx>
>> ---
>> Âkernel/trace/trace.c | Â Â3 ++-
>> Â1 files changed, 2 insertions(+), 1 deletions(-)
>>
>> diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
>> index a0174a4..15f0eec 100644
>> --- a/kernel/trace/trace.c
>> +++ b/kernel/trace/trace.c
>> @@ -2358,7 +2358,7 @@ static const char readme_msg[] =
>> Â Â Â Â "# mkdir /debug\n"
>> Â Â Â Â "# mount -t debugfs nodev /debug\n\n"
>> Â Â Â Â "# cat /debug/tracing/available_tracers\n"
>> - Â Â Â "wakeup preemptirqsoff preemptoff irqsoff ftrace sched_switch none\n\n"
>> + Â Â Â "wakeup preemptirqsoff preemptoff irqsoff function
>> sched_switch none\n\n"
>> Â Â Â Â "# cat /debug/tracing/current_tracer\n"
>> Â Â Â Â "none\n"
>> Â Â Â Â "# echo sched_switch > /debug/tracing/current_tracer\n"
>> @@ -2368,6 +2368,7 @@ static const char readme_msg[] =
>> Â Â Â Â "noprint-parent nosym-offset nosym-addr noverbose\n"
>> Â Â Â Â "# echo print-parent > /debug/tracing/trace_options\n"
>> Â Â Â Â "# echo 1 > /debug/tracing/tracing_enabled\n"
>> + Â Â Â "# chrt -f 5 sleep 1\n"
>> Â Â Â Â "# cat /debug/tracing/trace > /tmp/trace.txt\n"
>> Â Â Â Â "echo 0 > /debug/tracing/tracing_enabled\n"
>> Â;
>>
>
> Actually Nikanth sent a similar patch a month ago, but somehow it
> slipped under the radar. I'll be picking that one up instead.
>
> http://lkml.org/lkml/2009/3/23/24
>
> But thanks anyway.
>
> -- Steve
>
>
>



--
Regards,
GeunSik Lim
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