On Mon, Feb 21, 2011 at 03:44:11PM +0800, Li Zefan wrote:
> Han Pingtian wrote:
> > It seems we need echo -1 to set_ftrace_pid to disable in. Or we'll get
> > these error message when running ftrace_stress:
> >
>
> kernel version?
2.6.32-114.0.1.el6.x86_64 , RHEL6.1.
>
> This is the result from latest kernel:
>
> # echo > set_ftrace_pid
> # echo -1 > set_ftrace_pid
> bash: echo: write error: Invalid argument
>
Looks like latest kernel changed the behaviour. But the
Documentation/trace/ftrace.txt hasn't been updated:
yum-updatesd-3111 [003] 1637.254683: lock_hrtimer_base
<-hrtimer_try_to_cancel
yum-updatesd-3111 [003] 1637.254685: fget_light <-do_sys_poll
yum-updatesd-3111 [003] 1637.254686: pipe_poll <-do_sys_poll
# echo -1 > set_ftrace_pid
# cat trace |head
# tracer: function
#
# TASK-PID CPU# TIMESTAMP FUNCTION
Thanks.
> > ...
> > ftrace_stress_test/ftrace_stress/ftrace_set_ftrace_pid.sh: line 39: echo:
> > write error: Invalid argument
> > ...
> > ---
> > .../ftrace_stress/ftrace_set_ftrace_pid.sh | 2 +-
> > 1 files changed, 1 insertions(+), 1 deletions(-)
> >
> > diff --git
> > a/testcases/kernel/tracing/ftrace_stress_test/ftrace_stress/ftrace_set_ftrace_pid.sh
> >
> > b/testcases/kernel/tracing/ftrace_stress_test/ftrace_stress/ftrace_set_ftrace_pid.sh
> > index 541215c..bd08f04 100755
> > ---
> > a/testcases/kernel/tracing/ftrace_stress_test/ftrace_stress/ftrace_set_ftrace_pid.sh
> > +++
> > b/testcases/kernel/tracing/ftrace_stress_test/ftrace_stress/ftrace_set_ftrace_pid.sh
> > @@ -36,7 +36,7 @@ for ((; ; ))
> > eval echo $str >> "$TRACING_PATH"/set_ftrace_pid
> > }
> >
> > - echo > "$TRACING_PATH"/set_ftrace_pid
> > + echo -1 > "$TRACING_PATH"/set_ftrace_pid
> > }
> >
> > sleep 1
--
Han Pingtian
Quality Engineer
hpt @ #kernel-qe
Red Hat, Inc
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