On Fri, Aug 23, 2013 at 04:33:19PM +0800, Jiejing Zhang wrote: > > 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 <jiejzh...@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`
Yeah, or prod around in /proc yourself. > also with fork event, it can totally avoid add such a patch in kernel. Kinda depends on when you start tracing, if you start tracing when everything is already running you'll need a /proc state dump for the current state and the fork tracepoint can then update you on new tasks. Anyway, good to hear this works for you. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
