From mboxrd@z Thu Jan  1 00:00:00 1970
From: peterz@infradead.org (Peter Zijlstra)
Date: Tue, 10 Mar 2015 12:27:23 +0100
Subject: [PATCH 1/3] arm/pmu: Reject groups spanning multiple hardware PMUs
In-Reply-To: <1425905192-10509-2-git-send-email-suzuki.poulose@arm.com>
References: <1425905192-10509-1-git-send-email-suzuki.poulose@arm.com>
 <1425905192-10509-2-git-send-email-suzuki.poulose@arm.com>
Message-ID: <20150310112723.GY2896@worktop.programming.kicks-ass.net>
To: linux-arm-kernel@lists.infradead.org
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On Mon, Mar 09, 2015 at 12:46:30PM +0000, Suzuki K. Poulose wrote:
> From: "Suzuki K. Poulose" <suzuki.poulose@arm.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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Date: Tue, 10 Mar 2015 12:27:23 +0100
From: Peter Zijlstra <peterz@infradead.org>
To: "Suzuki K. Poulose" <suzuki.poulose@arm.com>
Cc: will.deacon@arm.com, linux@arm.linux.org.uk, acme@kernel.org,
        linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org,
        punit.agrawal@arm.com, pawel.moll@arm.com,
        Mark Rutland <mark.rutland@arm.com>
Subject: Re: [PATCH 1/3] arm/pmu: Reject groups spanning multiple hardware
 PMUs
Message-ID: <20150310112723.GY2896@worktop.programming.kicks-ass.net>
References: <1425905192-10509-1-git-send-email-suzuki.poulose@arm.com>
 <1425905192-10509-2-git-send-email-suzuki.poulose@arm.com>
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On Mon, Mar 09, 2015 at 12:46:30PM +0000, Suzuki K. Poulose wrote:
> From: "Suzuki K. Poulose" <suzuki.poulose@arm.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.