Re: [tip:perf/urgent] x86, perf events: Check if we have APIC enabled

[Cyrill Gorcunov <gorcunov@gmail.com>]

On Thu, Dec 10, 2009 at 05:18:32PM +0000, tip-bot for Cyrill Gorcunov wrote:
> Commit-ID:  125580380f418000b1a06d9a54700f1191b6e561
> Gitweb:     http://git.kernel.org/tip/125580380f418000b1a06d9a54700f1191b6e561
> Author:     Cyrill Gorcunov <gorcunov@openvz.org>
> AuthorDate: Thu, 10 Dec 2009 19:56:34 +0300
> Committer:  Ingo Molnar <mingo@elte.hu>
> CommitDate: Thu, 10 Dec 2009 18:00:30 +0100
> 
> x86, perf events: Check if we have APIC enabled
> 
> Ralf Hildebrandt reported this boot warning:
> 
> | Running a vanilla 2.6.32 as Xen DomU, I'm getting:
> |
> | [    0.000999] CPU: Physical Processor ID: 0
> | [    0.000999] CPU: Processor Core ID: 1
> | [    0.000999] Performance Events: AMD PMU driver.
> | [    0.000999] ------------[ cut here ]------------
> | [    0.000999] WARNING: at arch/x86/kernel/apic/apic.c:249 native_apic_write_dummy
> 
> So we need to check if APIC functionality is available, and
> not just in the P6 driver but elsewhere as well.
> 
> Reported-by: Ralf Hildebrandt <Ralf.Hildebrandt@charite.de>
> Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org>
> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
> Cc: Mike Galbraith <efault@gmx.de>
> Cc: Paul Mackerras <paulus@samba.org>
> Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
> Cc: Frederic Weisbecker <fweisbec@gmail.com>
> LKML-Reference: <20091210165634.GF5086@lenovo>
> Signed-off-by: Ingo Molnar <mingo@elte.hu>
> ---
>  arch/x86/kernel/cpu/perf_event.c |   18 ++++++++++++------
>  1 files changed, 12 insertions(+), 6 deletions(-)
>
...

Btw, is there some particular reason to have x86_pmu::apic item?
Can't we use cpu_has_apic directly? Or there some plans about
this item? Or I miss something obvious?
 
	-- Cyrill