linux-kernel - Re: 2.6.28-rc9: oprofile regression

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Date:	Thu, 15 Jan 2009 10:14:13 +0100
From:	Tim Blechmann <tim@...ngt.org>
To:	Thomas Gleixner <tglx@...utronix.de>
Cc:	Andi Kleen <ak@...ux.intel.com>, oprofile-list@...ts.sf.net,
	linux-kernel@...r.kernel.org,
	Robert Richter <robert.richter@....com>,
	venkatesh.pallipadi@...el.com
Subject: Re: 2.6.28-rc9: oprofile regression

On Thu, 2009-01-15 at 09:46 +0100, Thomas Gleixner wrote:
> Tim,
> 
> On Wed, 14 Jan 2009, Tim Blechmann wrote:
> > this code (line 81/82), changes counter_width from 32 to 40.
> > 
> > if (counter_width < eax.split.bit_width)
> >         counter_width = eax.split.bit_width;
> > 
> > however when removing these lines, and thus keeping the value 32 for
> > counter_width, doesn't change the behavior, only one NMI per cpu.
> 
> It would only help, when the reported bit_width would be bogus. We
> know that you get at least one NMI, so lets look at the results we get
> there.

it seems, that ppro_check_ctrs is never called:
[  982.238639] oprofile: using NMI interrupt.

hth, tim

--
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http://tim.klingt.org

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