Messages in this thread | | | Date | Fri, 23 Aug 2013 16:33:19 +0800 | From | Jiejing Zhang <> | Subject | Re: [PATCH] ftrace: add tgid information in task switch event. |
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On 08/21/2013 11:23 PM, Peter Zijlstra wrote: > On Wed, Aug 21, 2013 at 11:09:44AM -0400, Steven Rostedt wrote: >>> From: Jiejing Zhang <jiejzhang@nvidia.com> >>> >>> ftrace only report pid in task switch event, which is >>> actually thread ID in user space view, the comm of >>> the thread will be like "Thread-1", "Compiler", etc >>> in android system, it's useful if we can add tgid >>> information in ftrace event to find out the process >>> id, and the process id's comm will help us to figure >>> out the application, which was useful on data analysis >>> tools. > Meh.. are you telling me you really can't do that otherwise? > > Adding this information makes the tracepoint slower for everybody else. > How about you enable trace_sched_process_fork() and track things that > way? Thanks for the tip, I have tried fix this by avoid add tgid in ftrace, actually the relationship between thread and process can be figure by analysis these two command's output: `ps aTH -F` and `ps a -F`
also with fork event, it can totally avoid add such a patch in kernel.
Thanks. > > Also, last time I tried to change one of these stupid tracepoints > userspace broke.. Rostedt says people should be using libtraceevent but > I'm sceptical. > >>> Change-Id: Ia99f58a56d691d770b3beb2f76de0351e6194a4a > That needs to die.
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