Messages in this thread | | | Date | Thu, 21 Oct 2010 17:08:51 +0800 | Subject | Re: Ftrace: can trace kthread? | From | Yong Zhang <> |
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On Thu, Oct 21, 2010 at 4:59 PM, Figo.zhang <zhangtianfei@leadcoretech.com> wrote: > >> I just >> echo 0 > tracing_enabled >> echo function > current_tracer >> echo 374(pid of flush) > set_ftrace_pid >> echo 1 > tracing_enabled >> wait some time >> echo 0 > tracing_enabled >> cat trace >> >> So I think this answer your question "could kthread be traced?" > > i do it the same of you. > > [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.
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