From: Peter Zijlstra <peterz@infradead.org>
To: Borislav Petkov <bp@alien8.de>
Cc: Robert Richter <rric@kernel.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 11:04:51 +0200 [thread overview]
Message-ID: <20130517090451.GQ19669@dyad.programming.kicks-ass.net> (raw)
In-Reply-To: <20130516213420.GB31393@pd.tnic>
On Thu, May 16, 2013 at 11:34:20PM +0200, Borislav Petkov wrote:
> On Thu, May 16, 2013 at 10:55:58PM +0200, Robert Richter wrote:
> > iirc the reason was the different msr range that is switched on fam15h
> > with a different counter to counter msr offset of 2 instead of 1. The
> > code relies on the assumption that the msrs exist on that cpu. Thus
> > the warning if not. Also note that code may have changed in 3.10 in
> > that area.
>
> Stupid question: why is check_hw_exists() *after* the vendor-specific
> counter detection code in init_hw_perf_events() even though it is
> supposed to check whether hardware is emulated?
Mostly so that check_hw_exists() doesn't need to know about the vendor
specifics like where the MSRs live, how many there are etc..
next prev parent reply other threads:[~2013-05-17 9:06 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 [this message]
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
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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