linux-kernel - Re: [PATCH 1/3] arm/pmu: Reject groups spanning multiple hardware PMUs

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Date:	Tue, 10 Mar 2015 12:27:23 +0100
From:	Peter Zijlstra <peterz@...radead.org>
To:	"Suzuki K. Poulose" <suzuki.poulose@....com>
Cc:	will.deacon@....com, linux@....linux.org.uk, acme@...nel.org,
	linux-kernel@...r.kernel.org, linux-arm-kernel@...ts.infradead.org,
	punit.agrawal@....com, pawel.moll@....com,
	Mark Rutland <mark.rutland@....com>
Subject: Re: [PATCH 1/3] arm/pmu: Reject groups spanning multiple hardware
 PMUs

On Mon, Mar 09, 2015 at 12:46:30PM +0000, Suzuki K. Poulose wrote:
> From: "Suzuki K. Poulose" <suzuki.poulose@....com>
> 
> Don't allow grouping hardware events from different PMUs
>  (eg. CCI + CPU).

Uhm, how does this work? If we have multiple hardware PMUs we'll stop
scheduling events after the first failed event schedule. This can leave
one of the PMUs severely under utilized.
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