Re: [GIT PULL] updates for oprofile

[Robert Richter <robert.richter@amd.com>]

On 28.04.10 12:09:16, Phil Carmody wrote:
> On 28/04/10 18:59 +0200, ext Robert Richter wrote:
> > On 27.04.10 20:47:51, Siarhei Siamashka wrote:
> > > Isn't hrtimer callback function supposed to be only called from IRQ context
> > > after this cleanup: http://lwn.net/Articles/308545/ ?
> > 
> > Yes, the patch is upstream since v2.6.29. Thanks Siarhei.
> > 
> > I will add a null pointer check anyway.
> 
> A few here thrashed around a couple of ideas, and the general consensus 
> was that the following work for us, and is offered for consideration.
> 
> Phil
> 
> 
> From: Phil Carmody <ext-phil.2.carmody@nokia.com>
> Date: Tue, 27 Apr 2010 19:28:33 +0300
> Subject: [PATCH v2 1/1] oprofile: HACK - protect from not being in an IRQ context
> 
> http://lkml.org/lkml/2010/4/27/285
> 
> Protect against dereferencing regs when it's NULL, and
> force a magic number into pc to prevent too deep processing.
> This approach permits the dropped samples to be tallied as
> invalid Instruction Pointer events.
> 
> e.g. output from about 15mins at 10kHz sample rate:
> Nr. samples received: 2565380
> Nr. samples lost invalid pc: 4
> 
> Signed-off-by: Phil Carmody <ext-phil.2.carmody@nokia.com>

Patch applied to:

 git://git.kernel.org/pub/scm/linux/kernel/git/rric/oprofile.git core

Thanks Phil!

-Robert

-- 
Advanced Micro Devices, Inc.
Operating System Research Center
email: robert.richter@amd.com