Re: [GIT PULL] perf fixes

From: Ingo Molnar
Date: Thu Sep 12 2013 - 16:34:14 EST



* Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx> wrote:

> On Thu, Sep 12, 2013 at 11:10 AM, Linus Torvalds
> <torvalds@xxxxxxxxxxxxxxxxxxxx> wrote:
> >
> > But at least the "make install" problem is repeatable, though.
>
> And now this new problem is repeatable too:
>
> # On a fully built kernel tree
> perf record -g -e cycles:pp make -j
>
> results in
>
> [ perf record: Woken up 27 times to write data ]
> [ perf record: Captured and wrote 7.980 MB perf.data (~348659 samples) ]
> 0x1b4e0 [0]: failed to process type: -1970637019
>
> where that number changes randomly, ie I get
>
> 0x28dc58 [0]: failed to process type: 99257493
> 0x4100 [0]: failed to process type: -1144359783
> 0x29050 [0]: failed to process type: -972156963
> ..
>
> looks like perhaps some uninitialized variable somewhere?
>
> Recording performance profiles of other (simpler?) loads still seems to
> work. So it's something about that "make -j" that makes it crap out
> (note that the tree is fully built, so not a lot actually gets *done*,
> and the thing only takes a few seconds)

Hm, just to make sure, are you running a (very fresh) kernel that has this
fix included:

d008d5258e9c perf: Fix up MMAP2 buffer space reservation

?

Thanks,

Ingo
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