Messages in this thread | | | Date | Mon, 28 Apr 2008 09:05:20 -0400 (EDT) | From | Steven Rostedt <> | Subject | Re: [PATCH 2/3] ftrace: add trace pipe header pluggin |
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On Sat, 26 Apr 2008, Pekka Paalanen wrote:
> On Mon, 21 Apr 2008 17:09:37 -0400 > Steven Rostedt <rostedt@goodmis.org> wrote: > > > This patch adds a method for open_pipe and open_read to the pluggins > > so that they can add a header to the trace pipe call. > > > > Signed-off-by: Steven Rostedt <srostedt@redhat.com> > > In addition to this, I think I need tracer::close method called on > tracing_release_pipe(). Use case: the reader closes the pipe before > I have printed all of my header, i.e. walked through all PCI devices, > so I need to properly destroy trace_iterator::private.
Good idea, I'll add that.
> > I also intend to use trace_iterator::seq for printing my header, so I > am looking if I can reuse code from tracing_read_pipe(). Looks like I'll > extract the "return any leftover data" part into a separate function. > > To check trace_iterator::overrun, I'd like to be able to use > for_each_tracing_cpu(), but that is local to trace.c.
I'll look into that.
> > What happens when the tracing cpu mask changes? Mmiotrace does not take > that into account and will continue to record with all CPUs, will this > lead to problems, when mmiotrace starts to support SMP properly?
Good question. The tracing_cpu_mask isn't mine. So I'll need to know that answer too.
> > Now that I think of it, I probably want to use for_each_online_cpu() > in checking for overruns... but that's not good either, if someone > enables/disables a cpu during tracing. I guess you will have to / had to > deal with this case in tracing core, too.
Good point.
-- Steve
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