Re: [PATCH v5 00/45] CPU hotplug: stop_machine()-free CPU hotplug

From: Steven Rostedt
Date: Mon Feb 18 2013 - 14:53:34 EST

On Mon, 2013-02-18 at 17:50 +0100, Vincent Guittot wrote:

> yes for sure.
> The problem is more linked to cpuidle and function tracer.
> cpu hotplug and function tracer work when cpuidle is disable.
> cpu hotplug and cpuidle works if i don't enable function tracer.
> my platform is dead as soon as I enable function tracer if cpuidle is
> enabled. It looks like some notrace are missing in my platform driver
> but we haven't completely fix the issue yet

You can bisect to find out exactly what function is the problem:

cat /debug/tracing/available_filter_functions > t

f(t) {
num=`wc -l t`
sed -ne "1,${num}p" t > t1
let num=num+1
sed -ne "${num},$p" t > t2

cat t1 > /debug/tracing/set_ftrace_filter
# note this may take a long time to finish

echo function > /debug/tracing/current_tracer

<failed? bisect f(t1), if not bisect f(t2)>

-- Steve

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