Messages in this thread | | | Date | Sat, 8 May 2010 17:54:07 +0200 | From | Frederic Weisbecker <> | Subject | Re: [PATCH 0/2] perf: Redesign trace events reordering |
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On Wed, May 05, 2010 at 12:48:47AM -0500, Tom Zanussi wrote: > Hi Frederic, > > On Wed, 2010-05-05 at 02:03 +0200, Frederic Weisbecker wrote: > > I recently noticed that the new reordering design is broken > > when it deals with tons of events. > > > > This patchset provides another algorithm to deal with that, > > tested without any problem. > > > > And since it involves more frequent flushes, I guess it could > > plug nicely with the live mode. > > Very nice! I tried these out with live mode and it seems to work fine, > after applying the patch below. > > I initially had a problem with 'unexpected end of event stream' errors, > then noticed that the FINISHED_ROUND events were basically just headers > with no data, which caused the read of the 0-length payload to appear as > end-of-stream. > > I'll do some more testing (and fix some warnings in the scripts that > this mode seems to elicit), but it seems so far to work pretty well for > live mode... > > Tom
Cool, I'm applying your patch then,
Thanks.
> > From: Tom Zanussi <tzanussi@gmail.com> > Date: Wed, 5 May 2010 00:27:40 -0500 > Subject: [PATCH] perf/live-mode: handle payload-less events > > Some events, such as the PERF_RECORD_FINISHED_ROUND event consist of > only an event header and no data. In this case, a 0-length payload > will be read, and the 0 return value will be wrongly interpreted as an > 'unexpected end of event stream'. > > This patch allows for proper handling of data-less events by skipping > 0-length reads. > > Signed-off-by: Tom Zanussi <tzanussi@gmail.com> > --- > tools/perf/util/session.c | 19 +++++++++++-------- > 1 files changed, 11 insertions(+), 8 deletions(-) > > diff --git a/tools/perf/util/session.c b/tools/perf/util/session.c > index 9401909..00ab298 100644 > --- a/tools/perf/util/session.c > +++ b/tools/perf/util/session.c > @@ -696,15 +696,18 @@ more: > p = &event; > p += sizeof(struct perf_event_header); > > - err = do_read(self->fd, p, size - sizeof(struct perf_event_header)); > - if (err <= 0) { > - if (err == 0) { > - pr_err("unexpected end of event stream\n"); > - goto done; > - } > + if (size - sizeof(struct perf_event_header)) { > + err = do_read(self->fd, p, > + size - sizeof(struct perf_event_header)); > + if (err <= 0) { > + if (err == 0) { > + pr_err("unexpected end of event stream\n"); > + goto done; > + } > > - pr_err("failed to read event data\n"); > - goto out_err; > + pr_err("failed to read event data\n"); > + goto out_err; > + } > } > > if (size == 0 || > -- > 1.6.4.GIT > > >
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