Messages in this thread | | | Date | Tue, 22 Apr 2008 20:58:15 -0400 (EDT) | From | Steven Rostedt <> | Subject | Re: [PATCH 0/3] ftrace: overrun accounting and trace_pipe headers |
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On Tue, 22 Apr 2008, Pekka Paalanen wrote:
> Excellent!
Thanks ;-)
> > On Mon, 21 Apr 2008 17:09:35 -0400 > Steven Rostedt <rostedt@goodmis.org> wrote: > > > The first patch in this series adds accounting to record overruns. That is > > where the writing catches up to the reading of the buffer. This really > > only matters for trace_pipe since that's a consumer / producer output file. > > This takes me some thinking how to make the best of it, but looks like it > allows me to relay the overrun events into the trace log. Very good. > > > The next patch adds new methods for the plugins to hook into the > > open_pipe and open_read, to let a plugin produce a header. > > The open_read method can also be used to do something when overruns > > are detected. > > You mean pipe_open() and read()? :-) > And read() is pipe specific?
Yeah the read API is pipe specific (for now). I'll have to think about whether or not we should have a generic "read" and a "pipe_read"
> Ah, now I see what you mean by read() can be used to notice overruns: > it is called for every read syscall, not just in the beginning.
Right!
> > > The last patch is a test patch AND SHOULD NOT BE APPLIED. It is just an > > example in how to use the new methods to produce a header. It simply > > makes the ftrace tracer produce a simple "Test header" before any > > output. > > In function_read(), shouldn't I be doing something with filp and/or ppos?
Probably, that's why I said not to apply it ;-)
Thanks,
-- Steve
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