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SubjectRe: [PROBLEM] perf report is broken in latest linus git
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On Thu, 2009-08-13 at 12:47 +0300, Pekka Enberg wrote:
> Hi Ingo,
>
> On Thu, 2009-08-13 at 11:36 +0200, Ingo Molnar wrote:
> > * Pekka Enberg <penberg@cs.helsinki.fi> wrote:
> >
> > > Latest Linus git kernel with -rc4 perf userspace:
> > >
> > > penberg@penberg-laptop:~/testing/jato$ perf record -f jato HelloWorldSwing
> > > [ perf record: Captured and wrote 1.402 MB perf.data (~61261 samples) ]
> > >
> > > penberg@penberg-laptop:~/testing/jato$ perf report --sort comm,dso,symbol|head -30
> > > # Samples: 60457
> > > #
> > > # Overhead Command Shared Object Symbol
> > > # ........ ....... ....................................... ......
> > > #
> > >
> > > [ Note: the jato executable doesn't appear anywhere in the trace. I'm
> > > pretty sure the libzip functions, for example, are from jato, not perf. ]
> > >
> > > 36.14% perf /home/penberg/bin/perf [.] dso__synthesize_plt_symbols
> > > 35.20% perf /home/penberg/bin/perf [.] dso__new
> > > 3.57% perf /home/penberg/bin/jato [.] 0x0000000000c910
> >
> > Perhaps it's this commit:
> >
> > 4d1e00a: perf symbol: Fix symbol parsing in certain cases: use the build-id as a symlink
> >
> > it does not revert cleanly, so you might want to check out these two
> > commits:
> >
> > 4d1e00a
> > 4d1e00a~1
> >
> > and build perf on both, and check with your anomalous perf.data
> > (without changing it) whether the output makes most sense.
>
> The commit seems fine. Like I said, the perf.data file is busted even
> with 2.6.31-rc4 userspace so I think it's a kernel bug.

Hrmm, does a -tip kernel work as expected? I'll go audit the kernel
changes between -rc4 and -rc5.


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