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
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=1263211680.4244.50.camel@laptop \
--to=peterz@infradead.org \
--cc=efault@gmx.de \
--cc=linux-kernel@vger.kernel.org \
--cc=ming.m.lin@intel.com \
--cc=mingo@elte.hu \
--cc=tglx@linutronix.de \
--cc=yanmin_zhang@linux.intel.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.