From: Andrew Morton <akpm@digeo.com>
To: "Martin J. Bligh" <mbligh@aracnet.com>
Cc: bzzz@tmi.comex.ru, linux-kernel@vger.kernel.org, linux-mm@kvack.org
Subject: Re: 2.5.66-mm2
Date: Tue, 1 Apr 2003 17:34:02 -0800 [thread overview]
Message-ID: <20030401173402.2a6f728f.akpm@digeo.com> (raw)
In-Reply-To: <151780000.1049245829@flay>
"Martin J. Bligh" <mbligh@aracnet.com> wrote:
>
> Ho hum. All very strange. Kernbench seems to be really behaving itself
> quite well now, but SDET sucks worse than ever. The usual 16x NUMA-Q
> machine ....
>
> Kernbench: (make -j N vmlinux, where N = 2 x num_cpus)
> Elapsed System User CPU
> 2.5.66-mm2 44.04 81.12 569.40 1476.75
> 2.5.66-mm2-ext3 44.43 84.10 568.82 1469.00
Is this ext2 versus ext3? If so, that's a pretty good result isn't it? I
forget what kernbench looked like for stock ext3.
> SDET 32 (see disclaimer)
> Throughput Std. Dev
> 2.5.66-mm2 100.0% 0.7%
> 2.5.66-mm2-ext3 4.7% 1.5%
Yes, this is presumably a lot more metadata-intensive, so we're just
hammering the journal semaphore to death. We're working on it.
> ftp://ftp.kernel.org/pub/linux/kernel/people/mbligh/benchmarks/2.5.66-mm2-ext3/
Offtopic, a raw sdet64 profile says:
5392317 total
4478683 default_idle
307163 __down
169770 .text.lock.sched
106769 schedule
88092 __wake_up
57280 .text.lock.transaction
I'm slightly surprised that the high context switch rate is showing up so
much contention in sched.c. I'm assuming that it's on the sleep/wakeup path
and not in the context switch path. It would be interesting to inline the
spinlock code and reprofile.
We really should be using the waker-removes-wakee facility in the semaphore
code, but that's not completely trivial.
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next prev parent reply other threads:[~2003-04-02 1:34 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2003-04-01 8:01 2.5.66-mm2 Andrew Morton
2003-04-01 8:48 ` 2.5.66-mm2 Andrew Morton
2003-04-01 9:15 ` 2.5.66-mm2 Andrew Morton
2003-04-02 1:10 ` 2.5.66-mm2 Martin J. Bligh
2003-04-02 1:34 ` Andrew Morton [this message]
2003-04-02 15:34 ` 2.5.66-mm2 Martin J. Bligh
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