Re: [patch] Performance Counters for Linux, v3

Ingo Molnar
2008-12-12T06:22:39Z

* Andrew Morton <akpm@linux-foundation.org> wrote:

> On Thu, 11 Dec 2008 16:52:30 +0100
> Ingo Molnar <mingo@elte.hu> wrote:
>
> > To: linux-kernel@vger.kernel.org
> > Cc: Thomas Gleixner <tglx@linutronix.de>, Andrew Morton <akpm@linux-foundation.org>, Stephane Eranian <eranian@googlemail.com>, Eric Dumazet <dada1@cosmosbay.com>, Robert Richter <robert.richter@amd.com>, Arjan van de Veen <arjan@infradead.org>, Peter Anvin <hpa@zytor.com>, Peter Zijlstra <a.p.zijlstra@chello.nl>, Paul Mackerras <paulus@samba.org>, "David S. Miller" <davem@davemloft.net>
>
> Please copy perfctr-devel@lists.sourceforge.net on all this. That is
> where the real-world people who use these facilities on a regular basis
> hang out.

Sure, we'll do that for v4.

The reason we kept posting this to lkml initially was because there is a
visible detachment of this community from kernel developers. And that is
at least in part because this stuff has never been made interesting
enough to kernel developers. I dont remember a _single_ perfmon-generated
profile (be that user-space or kernel-space) in my mailbox before - and
optimizing the kernel is supposed to be one of the most important aspects
of performance tuning.

That's why we concentrate on making this useful and interesting to kernel
developers too via KernelTop, that's why we made the BTS/[PEBS] hardware
tracer available via an ftrace plugin, etc.

Furthermore, kernel developers tend to be quite good at co-designing,
influencing [and flaming ;-) ] such APIs at the early prototype stages,
so the main early technical feedback we were looking for on the kernel
side structure was lkml. But the wider community is not ignored either,
of course - with v4 it might be useful already for wider circulation.

Ingo