Re: Ftrace: can trace kthread?

Figo.zhang
2010-10-21T09:56:49Z

> >
> > [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?