Re: [GIT PULL] Performance Counters for Linux

Ingo Molnar
2009-06-12T10:28:27Z

* stephane eranian <eranian@googlemail.com> wrote:

> Hi,
>
> On Thu, Jun 11, 2009 at 6:03 PM, Ingo Molnar <mingo@elte.hu> wrote:
>
> > The counter concept got objected to in past discussions on lkml,
> > by DaveM and by Stephane Eranian (i've Cc:-ed them) - so this
> > code was not eligible for linux-next testing - nevertheless we
> > gave it good testing on PowerPC and x86 and i've done a wide
> > cross-build test as well to try to make sure it breaks no other
> > architecture.
>
> I don't think you can quote me saying "I object to this code".
> [...]

I never saw you retract/change this negative opinion of yours about
the whole separate-counters concept:

" In summary, although the idea of simplifying tools by moving the
complexity elsewhere is legitimate, pushing it down to the
kernel is the wrong approach in my opinion, perfmon has avoided
that as much as possible for good reasons. "

http://lkml.org/lkml/2008/12/5/359

Do you like the concept now? That would be great news - you have a
lot of experience with various PMU details and we could certainly
welcome help with the perf tool and with the kernel side of
perfcounters!

> [...] I posted a detailed review of the API and implementation on
> X86 outlining lots of issues. Some got fixed, but many others are
> left unresolved at this point. And I will post some more shortly.

Hm, Peter replied to you mail a week ago, in detail. We addressed a
good number of issues pointed out by you, and we credited you for
them:

earth4:~/tip> git log v2.6.30..linus | grep 'Reported-by: Stephane Eranian'
Reported-by: Stephane Eranian <eranian@googlemail.com>
Reported-by: Stephane Eranian <eranian@googlemail.com>
Reported-by: Stephane Eranian <eranian@googlemail.com>
Reported-by: Stephane Eranian <eranian@googlemail.com>
Reported-by: Stephane Eranian <eranian@googlemail.com>
Reported-by: Stephane Eranian <eranian@googlemail.com>
Reported-by: Stephane Eranian <eranian@googlemail.com>

You were on the Cc: of the commit notifications. If you see issues
left unaddressed after reply+commit please repeat it - it probably
just got lost in noise.

> I don't think that because this code is coming from you, it should
> be allowed to short-circuit the established release process. You
> have to respond to questions, fix issues like everybody else and
> if that slows down the integration you cannot blame the reviewers
> for it.

There's three maintainers of perfcounters: Peter Zijlstra, Paul
Mackerras and me - and if some real problem missed the attention of
all of us then please repeat it - it probably was just missed in a
bigger mail or so. I certainly dont remember anything major. We
generally try to reply to any and all feedback.

Thanks,

Ingo