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

From: GeunSik Lim
Date: Mon Apr 06 2009 - 10:17:55 EST


I attached patch file again because no-operation is changed
from "none"word to "nop" word.

for example,
- "wakeup preemptirqsoff preemptoff irqsoff ftrace sched_switch none\n\n"
+ "wakeup preemptirqsoff preemptoff irqsoff function sched_switch nop\n\n"

./trace_nop.c:struct tracer nop_trace __read_mostly =
.name = "nop",
.init = nop_trace_init,
.reset = nop_trace_reset,
.selftest = trace_selftest_startup_nop,
.flags = &nop_flags,
.set_flag = nop_set_flag



2009/4/6 GeunSik Lim <leemgs1@xxxxxxxxx>:
> Â Dear Steven,
>
> Â The author of ftrace(Internal kernel Function Tracer) feature
> renamed the ftrace tracer
> Â Âto function to avoid further confusion between the ftrace
> infrastructure and the
> Â Âfunction tracer on Oct-20, 2008.
>
> Â ÂBut, Update of Mini-HOWTO document are still not working
> Â Â.
> Â ÂMost of the developers often utilize "/debug/tracing/README" file
> as Mini-HOWTO.
> Â ÂThey will confuse definition and usage about ftrace Âbetween
> README(ftrace) file
> Â Âand available_tracers(function) file after linux-2.6.27 like me.
> Â ÂAnd, I want you to append "chrt -f 5 sleep 1" command as simple
> example for latency.
>
> Â ÂSigned-off-by: GeunSik Lim <leemgs1@xxxxxxxxx>
> Â ÂSigned-off-by: Steven Rostedt <srostedt@xxxxxxxxxx>
> Â ÂSigned-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;
>
>
>
> --
> Regards,
> GeunSik Lim
> --
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--
Regards,
GeunSik Lim
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Attachment: update-minihowto-ftrace-nop.patch
Description: Binary data