Re: [PATCH v2] perf, x86: Fix event scheduler for constraints with overlapping counters

From: Robert Richter <robert.richter@amd.com>
To: Peter Zijlstra <peterz@infradead.org>
Cc: Ingo Molnar <mingo@elte.hu>,
	Stephane Eranian <eranian@google.com>,
	LKML <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH v2] perf, x86: Fix event scheduler for constraints with overlapping counters
Date: Thu, 19 May 2011 12:49:01 +0200	[thread overview]
Message-ID: <20110519104901.GC12404@erda.amd.com> (raw)
In-Reply-To: <1305754613.2466.7190.camel@twins>

On 18.05.11 17:36:53, Peter Zijlstra wrote:
> On Wed, 2011-05-18 at 23:20 +0200, Ingo Molnar wrote:
> > * Peter Zijlstra <peterz@infradead.org> wrote:
> > 
> > > >                         if (c->weight != w)
> > > >                                 continue;
> > > >  
> > > > -                       for_each_set_bit(j, c->idxmsk, X86_PMC_IDX_MAX) {
> > > > -                               if (!test_bit(j, used_mask))
> > > > +                       /* for each bit in idxmsk starting from idx */
> > > > +                       while (idx < X86_PMC_IDX_MAX) {
> > > > +                               idx = find_next_bit(c->idxmsk, X86_PMC_IDX_MAX,
> > > > +                                                   idx);
> > > 
> > > I'd be mighty tempted to ignore that 80 column rule here ;-)
> > 
> > Please put the body of the loop into a helper function, the function is large 
> > and there are countless col80 uglinesses in it!
> 
> I just tried that, its real ugly due to the amount of state you need to
> pass around.

I will try to improve the patch and send a new version.

Thanks for review.

-Robert

-- 
Advanced Micro Devices, Inc.
Operating System Research Center