Re: [GIT PULL] perf fixes

From: Ingo Molnar
Date: Mon Jan 24 2011 - 16:25:56 EST



* Arnaldo Carvalho de Melo <acme@xxxxxxxxxx> wrote:

> Em Tue, Jan 25, 2011 at 06:27:31AM +1000, Linus Torvalds escreveu:
> > On Tue, Jan 25, 2011 at 6:17 AM, Linus Torvalds
> > <torvalds@xxxxxxxxxxxxxxxxxxxx> wrote:
> > >
> > > It only happens for me with "g". With "perf record -af sleep 10" it worked.
> >
> > Actually, it's something subtler than that. It must depend on the
> > actual data, because now when I tried it again, it worked with 'g'
> > too. I hadn't saved the old perf.data that caused the lockup (it got
> > overwritten by the non-g test), and now when I try to re-create it it
> > doesn't hang on the result.
> >
> > So it's probably some very specific data pattern that causes it.
> >
> > (And I don't know if it's a hard hang - it could just be something
> > _very_ slow. But we're talking half a minute kind of slow).
>
> Was this on a freshly installed machine? Or on a freshly updated one?
>
> Probably its the build-id collecting at the end of a session, on the
> first run you had a cold cache and it had to figure out which binaries
> to cache on ~/.debug, second time it was already cached so it was fast.

Hm, it would be nice to not surprise users with an unlimited-timeout, up to half a
minute 'frozen' app. Can we possibly display a more finegrained progress indicator?

Thanks,

Ingo
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