Re: Ftrace: can trace kthread?

KOSAKI Motohiro
2010-10-21T10:08:34Z

>
> > >
> > > [root@myhost tracing]# ps -ax | grep flush
> > > Warning: bad ps syntax, perhaps a bogus '-'? See http://procps.sf.net/faq.html
> > > 1205 ? S 0:01 [flush-8:0]
> > > 11852 pts/1 S+ 0:00 grep flush
> > > [root@myhost tracing]#
> > >
> > > so my flusher pid is 1205, i do it as below:
> > >
> > > [root@myhost tracing]# echo 0 > tracing_enabled
> > > [root@myhost tracing]# echo function > current_tracer
> > > [root@myhost tracing]# echo 1205 > set_ftrace_pid
> > > [root@myhost tracing]# echo 1 > tracing_enabled
> > >
> > > wait ... and open some pdf files, let system eat huge memory...
> > >
> > > [root@myhost tracing]# echo 0 > tracing_enabled
> > > [root@myhost tracing]# cat trace
> > > # tracer: function
> > > #
> > > # TASK-PID CPU# TIMESTAMP FUNCTION
> > > # | | | | |
> > >
> > >
> > > but i canot trace nothing.
> >
> > Is tracing_on enable(1) on your system?
> > I enable it on my system by default, so I didn't show it in the previous mail.
> >
>
> tracing_on is sure on, my kernel is 2.6.36-rc8, what is your kernel
> version?

2.6.36-rc8 + Yong's way works perfectly fine on my x86_64 desktop.

thanks.