From: Andi Kleen <andi@firstfloor.org>
To: Robert Richter <robert.richter@amd.com>
Cc: Ingo Molnar <mingo@kernel.org>,
LKML <linux-kernel@vger.kernel.org>,
oprofile-list <oprofile-list@lists.sourceforge.net>,
Andi Kleen <andi@firstfloor.org>
Subject: Re: [PATCH 2/2] oprofile: Remove 'WQ on CPUx, prefer CPUy' warning
Date: Mon, 27 Aug 2012 18:08:54 +0200 [thread overview]
Message-ID: <20120827160854.GC16230@one.firstfloor.org> (raw)
In-Reply-To: <1345834411-24940-3-git-send-email-robert.richter@amd.com>
On Fri, Aug 24, 2012 at 08:53:31PM +0200, Robert Richter wrote:
> Under certain workloads we see the following warnings:
>
> WQ on CPU0, prefer CPU1
> WQ on CPU0, prefer CPU2
> WQ on CPU0, prefer CPU3
>
> It warns the user that the wq to access a per-cpu buffers runs not on
> the same cpu. This happens if the wq is rescheduled on a different cpu
> than where the buffer is located. This was probably implemented to
> detect performance issues. Not sure if there actually is one as the
> buffers are copied to a single buffer anyway which should be the
> actual bottleneck.
>
> We wont change WQ implementation. Since a user can do nothing the
> warning is pointless. Removing it.
Looks good to me.
Acked-by: Andi Kleen <ak@linux.intel.com>
-Andi
prev parent reply other threads:[~2012-08-27 16:09 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-08-24 18:53 [PATCH 0/2] oprofile fixes and updates Robert Richter
2012-08-24 18:53 ` [PATCH 1/2] oprofile, s390: Fix uninitialized memory access when writing to oprofilefs Robert Richter
2012-08-24 18:53 ` [PATCH 2/2] oprofile: Remove 'WQ on CPUx, prefer CPUy' warning Robert Richter
2012-08-27 16:08 ` Andi Kleen [this message]
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