From: Robert Richter <rric@kernel.org>
To: Borislav Petkov <bp@alien8.de>
Cc: Peter Zijlstra <peterz@infradead.org>,
Josh Boyer <jwboyer@redhat.com>, Ingo Molnar <mingo@redhat.com>,
Arnaldo Carvalho de Melo <acme@ghostprotocols.net>,
x86@kernel.org, linux-kernel@vger.kernel.org, gleb@redhat.com
Subject: Re: Drop WARN on AMD lack of perfctrs
Date: Fri, 17 May 2013 12:36:00 +0200 [thread overview]
Message-ID: <20130517103600.GG8356@rric.localhost> (raw)
In-Reply-To: <20130517094551.GE23035@pd.tnic>
On 17.05.13 11:45:51, Borislav Petkov wrote:
> On Fri, May 17, 2013 at 11:27:41AM +0200, Peter Zijlstra wrote:
> > But not all x86 hardware even has the stuff enumerated in CPUID, and
> > afaict Intel and AMD use a different CPUID bit as well, so what's
> > init_hw_perf_events() to do?
>
> Yeah, I think the best solution would be if we force-enable the CPUID
> bit on F10h very early and teach amd_pmu_init() to look at it. I even
> had a patch which does something like that. I could dust it off and give
> it a try... I just hope we can actually enable a reserved bit in CPUID.
The cpuid bit indicates perfctrs that do not exist, this will setup a
wrong msr range on f10h. I guess the warning is harmless and the code
works properly, but I can't tell for sure now and need to look at it.
Also, the problem occurs on f15h there *no* core perfctrs exist but
are expected, not on a f10h system.
-Robert
next prev parent reply other threads:[~2013-05-17 10:36 UTC|newest]
Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-05-16 15:10 Drop WARN on AMD lack of perfctrs Josh Boyer
2013-05-16 17:51 ` Peter Zijlstra
2013-05-16 17:55 ` Josh Boyer
2013-05-16 18:10 ` Peter Zijlstra
2013-05-16 20:55 ` Robert Richter
2013-05-16 21:34 ` Borislav Petkov
2013-05-17 9:04 ` Peter Zijlstra
2013-05-17 9:16 ` Borislav Petkov
2013-05-17 9:27 ` Peter Zijlstra
2013-05-17 9:45 ` Borislav Petkov
2013-05-17 10:36 ` Robert Richter [this message]
2013-05-17 10:57 ` Peter Zijlstra
2013-05-21 8:56 ` Robert Richter
2013-05-21 11:05 ` Peter Zijlstra
2013-05-21 13:58 ` Robert Richter
2013-05-21 15:20 ` Jacob Shin
2013-05-28 13:03 ` [tip:perf/core] perf/x86/amd: Rework AMD PMU init code tip-bot for Peter Zijlstra
2013-05-16 21:54 ` Drop WARN on AMD lack of perfctrs Josh Boyer
2013-05-16 22:33 ` Robert Richter
2013-05-16 19:31 ` Gleb Natapov
2013-05-16 20:00 ` Borislav Petkov
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