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From: Jiri Olsa <jolsa@redhat.com>
To: Peter Zijlstra <peterz@infradead.org>
Cc: Jiri Olsa <jolsa@kernel.org>,
	"Liang, Kan" <kan.liang@linux.intel.com>,
	Stephane Eranian <eranian@google.com>,
	Andy Lutomirski <luto@kernel.org>,
	lkml <linux-kernel@vger.kernel.org>,
	Ingo Molnar <mingo@kernel.org>,
	Namhyung Kim <namhyung@kernel.org>,
	Alexander Shishkin <alexander.shishkin@linux.intel.com>,
	Andi Kleen <ak@linux.intel.com>,
	Vince Weaver <vincent.weaver@maine.edu>,
	Thomas Gleixner <tglx@linutronix.de>,
	Arnaldo Carvalho de Melo <acme@kernel.org>,
	Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Subject: Re: [PATCH 0/8] perf/x86: Rework msr probe interface
Date: Tue, 28 May 2019 12:22:20 +0200	[thread overview]
Message-ID: <20190528102220.GA4917@krava> (raw)
In-Reply-To: <20190528100147.GM2623@hirez.programming.kicks-ass.net>

On Tue, May 28, 2019 at 12:01:47PM +0200, Peter Zijlstra wrote:
> On Mon, May 27, 2019 at 11:51:21PM +0200, Jiri Olsa wrote:
> > hi,
> > following up on [1], [2] and [3], this patchset adds update
> > attribute groups to pmu, factors out the MSR probe code and
> > use it in msr,cstate* and rapl PMUs.
> > 
> > The functionality stays the same with one exception:
> > the event is not exported if the rdmsr return zero
> > on event's msr.
> 
> That seems a wee bit dangerous, are we sure none of these counters are 0
> by 'accident' when we probe them? I'm thinking esp. things like the Cn
> residency stuff could be 0 simply because we've not been into that state
> yet.

ah right, I can disable that check for cstate pmu
and perhaps for msr pmu as well

It's aiming for rapl counters which could return 0
for unsupported counters, agreed by Kan before:

https://lore.kernel.org/lkml/5fcaf3ae-00d3-f635-74bd-8b81a089133f@linux.intel.com/

jirka

> 
> Other than that, this looks good. Kan?

      reply	other threads:[~2019-05-28 10:22 UTC|newest]

Thread overview: 11+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-05-27 21:51 [PATCH 0/8] perf/x86: Rework msr probe interface Jiri Olsa
2019-05-27 21:51 ` [PATCH 1/8] perf/x86: Add " Jiri Olsa
2019-05-27 21:51 ` [PATCH 2/8] perf/x86/msr: Use new probe function Jiri Olsa
2019-05-27 21:51 ` [PATCH 3/8] perf/x86/cstate: " Jiri Olsa
2019-05-27 21:51 ` [PATCH 4/8] perf/x86/rapl: Use new msr detection interface Jiri Olsa
2019-05-27 21:51 ` [PATCH 5/8] perf/x86/rapl: Get rapl_cntr_mask from new probe framework Jiri Olsa
2019-05-27 21:51 ` [PATCH 6/8] perf/x86/rapl: Get msr values " Jiri Olsa
2019-05-27 21:51 ` [PATCH 7/8] perf/x86/rapl: Get attributes " Jiri Olsa
2019-05-27 21:51 ` [PATCH 8/8] perf/x86/rapl: Get quirk state " Jiri Olsa
2019-05-28 10:01 ` [PATCH 0/8] perf/x86: Rework msr probe interface Peter Zijlstra
2019-05-28 10:22   ` Jiri Olsa [this message]

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