Re: [perfmon] Re: [PATCH 1/2] Separate the performance counter allocation from the LAPIC NMI watchdog

[Stephane Eranian <eranian@hpl.hp.com>]

Bjorn,


On Wed, Jun 20, 2007 at 02:59:33PM -0700, Stephane Eranian wrote:
> Bjorn,
> 
> I ran into one issue related with the new allocator.
> 
> In the case of a Core 2 Duo processor, the PMU implements more
> than just basic counters. In particular it supports fixed counters
> and PEBS where both use another set of MSRs. Those are not within
> a 66 bit distance from MSR_ARCH_PERFMON_EVNTSEL0. Thus the allocator
> fails with an assertion.
> 
> I do know that perfmon is the only consumer of those extended 
> features TODAY. Yet I think we need to define the allocator such
> that it can work with other "distant" MSRs as well.
> 

I think that a workaround for this issue could be for the allocator
to grant the requests for registers outside of the range, i.e., register
that it does not see/manage.

> On Wed, Jun 20, 2007 at 08:33:15PM +0200, Bj?rn Steinbrink wrote:
> > On 2007.06.20 15:01:02 +0200, Andi Kleen wrote:
> > > 
> > > > Once this is fixed (which is what Bjorn did), then I will agree with you.
> > > > For this, the allocator needs to be able to probe the CPU and initialize
> > > > its own data structures.
> > > 
> > > Ok that sounds reasonable. Please someone send a patch that does only 
> > > that.
> > 
> > OK, here come the bugfixes without any restructuring. The first patch
> > enables unconditional probing of the watchdog. The second makes the
> > perfmon nmi watchdog reserve the correct perfctr/evntsel.
> > 
> > Björn
> > 
> > -------------------------------------------------------------------------
> > This SF.net email is sponsored by DB2 Express
> > Download DB2 Express C - the FREE version of DB2 express and take
> > control of your XML. No limits. Just data. Click to get it now.
> > http://sourceforge.net/powerbar/db2/
> > _______________________________________________
> > oprofile-list mailing list
> > oprofile-list@lists.sourceforge.net
> > https://lists.sourceforge.net/lists/listinfo/oprofile-list
> 
> -- 
> 
> -Stephane
> _______________________________________________
> perfmon mailing list
> perfmon@linux.hpl.hp.com
> http://www.hpl.hp.com/hosted/linux/mail-archives/perfmon/

-- 

-Stephane
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/