From: Peter Zijlstra <peterz@infradead.org>
To: Lin Ming <ming.m.lin@intel.com>
Cc: mingo@elte.hu, tglx@linutronix.de,
linux-kernel <linux-kernel@vger.kernel.org>,
"Zhang, Yanmin" <yanmin_zhang@linux.intel.com>,
Mike Galbraith <efault@gmx.de>
Subject: Re: tbench regression with 2.6.33-rc1
Date: Mon, 11 Jan 2010 13:08:00 +0100 [thread overview]
Message-ID: <1263211680.4244.50.camel@laptop> (raw)
In-Reply-To: <1261739467.10685.18.camel@minggr.sh.intel.com>
On Fri, 2009-12-25 at 19:11 +0800, Lin Ming wrote:
> Hi,
>
> Test machine: 16 cpus (4P/2Core/HT), 8G mem
> tbench test command:
> tbench_srv &
> tbench 32
>
> Compared with 2.6.32, tbench has ~4% regression in 2.6.33-rc1.
>
> >From vmstat data, the context switch number also drop ~4%.
> perf top data does not show much differences.
>
> But lockstat data shows huge difference in rq->lock, as below.
> See the attachment for the full lockstat data.
>
> Any clue of this regression?
Nope, I thought to see the same on a dual-socket machine, but when
bisecting I ended up on a user-space perf commit, which is pretty much
impossible.
I did notice some variance in the numbers between boots, maybe it was
large enough to fool me.. (~2800 MB/s was the good one, ~2200 MB/s was
the bad one).
perf itself also didn't really provide clue, perf record -ag on the
workload didn't really show anything scheduler related. vmstat 1 did
show a proportional drop in context switch rate between the kernels
though.. most odd.
next prev parent reply other threads:[~2010-01-11 12:08 UTC|newest]
Thread overview: 22+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-12-25 11:11 tbench regression with 2.6.33-rc1 Lin Ming
2009-12-27 8:32 ` Mike Galbraith
2009-12-27 8:59 ` Peter Zijlstra
2009-12-27 9:41 ` Mike Galbraith
2009-12-27 10:11 ` Peter Zijlstra
2010-01-02 3:56 ` Frederic Weisbecker
2009-12-29 2:09 ` Lin Ming
2009-12-29 5:24 ` Mike Galbraith
2009-12-29 5:19 ` Lin Ming
2009-12-29 5:49 ` Mike Galbraith
2010-01-06 6:01 ` Mike Galbraith
2010-01-06 5:55 ` Lin Ming
2010-01-06 6:52 ` Lin Ming
2010-01-06 7:44 ` Mike Galbraith
2010-01-11 12:08 ` Peter Zijlstra [this message]
2010-01-11 16:16 ` Mike Galbraith
2010-01-12 1:09 ` Lin Ming
2010-01-12 2:33 ` Mike Galbraith
2010-01-12 3:13 ` Lin Ming
2010-01-12 4:14 ` Mike Galbraith
2010-01-12 8:54 ` Peter Zijlstra
2010-01-12 9:20 ` Lin Ming
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