From: <ognen@gene.pbi.nrc.ca>
To: Davide Libenzi <davidel@xmailserver.org>
Cc: <linux-kernel@vger.kernel.org>
Subject: Re: threading question
Date: Tue, 12 Jun 2001 15:48:34 -0600 (CST) [thread overview]
Message-ID: <Pine.LNX.4.30.0106121546510.11222-100000@gene.pbi.nrc.ca> (raw)
In-Reply-To: <XFMail.20010612144449.davidel@xmailserver.org>
Hello,
a good suggestion was given to me to actually create as many threads as
there are CPUs (or a bit more) and then keep them asking for work when
they are done. This should help it (and avoid the pthread_create,
pthread_exit). I will implement this and report my results if there is
interest.
Thank you all,
Ognen
On Tue, 12 Jun 2001, Davide Libenzi wrote:
>
> On 12-Jun-2001 Christoph Hellwig wrote:
> > In article <Pine.LNX.4.30.0106121213570.24593-100000@gene.pbi.nrc.ca> you
> > wrote:
> >> On dual-CPU machines the speedups are as follows: my version
> >> is 1.88 faster than the sequential one on IRIX, 1.81 times on Solaris,
> >> 1.8 times on OSF/1, 1.43 times on Linux 2.2.x and 1.52 times on Linux 2.4
> >> kernel. Why are the numbers on Linux machines so much lower?
> >
> > Does your measurement include the time needed to actually create the
> > threads or do you even frequently create and destroy threads?
>
> This is an extract of the most busy vmstat report running under his tool :
>
> 12 0 0 15508 40980 24880 355480 0 0 0 0 141 481 100 0 0
> 19 0 0 15508 40248 24880 355480 0 0 0 0 142 564 100 0 0
> 12 0 0 15508 40112 24880 355480 0 0 0 0 150 543 100 0 0
> 11 0 0 15508 41272 24880 355480 0 0 0 0 156 594 99 1 0
> 17 0 0 15508 40408 24880 355480 0 0 0 0 156 474 99 1 0
> 17 0 0 15508 39840 24880 355480 0 0 0 0 135 475 100 0 0
> 21 0 0 15508 39568 24880 355480 0 0 0 0 125 409 100 0 0
> 21 0 0 15508 39668 24880 355480 0 0 0 0 135 420 100 0 0
> 16 0 0 15508 39760 24880 355480 0 0 0 0 149 486 100 0 0
>
>
> The context switch is very low and the user CPU utilization is 100% , I don't
> think it's system responsibility here ( clearly a CPU bound program ).
> Even if the runqueue is long, the context switch is low.
> I've just close to me a dual PIII 1GHz workstation that run an MTA that uses
> linux pthreads with context switching ranging between 5000 and 11000 with a
> thread creation rate of about 300 thread/sec ( relaying 600000 msg/hour ).
> No problem at all with the system even if the load avg is a bit high
> ( about 8 ).
--
Ognen Duzlevski
Plant Biotechnology Institute
National Research Council of Canada
Bioinformatics team
next prev parent reply other threads:[~2001-06-12 21:50 UTC|newest]
Thread overview: 38+ messages / expand[flat|nested] mbox.gz Atom feed top
2001-06-12 18:24 threading question ognen
2001-06-12 18:39 ` Davide Libenzi
2001-06-12 18:57 ` from dmesg: kernel BUG at inode.c:486 Olivier Sessink
2001-06-12 18:58 ` threading question Christoph Hellwig
2001-06-12 19:07 ` ognen
2001-06-12 19:15 ` Kip Macy
2001-06-12 19:29 ` Christoph Hellwig
2001-06-12 19:15 ` Christoph Hellwig
2001-06-13 12:20 ` Kurt Garloff
2001-06-13 13:35 ` J . A . Magallon
2001-06-13 14:17 ` Philips
2001-06-13 15:06 ` ognen
2001-06-12 21:44 ` Davide Libenzi
2001-06-12 21:48 ` ognen [this message]
2001-06-14 18:15 ` Alan Cox
2001-06-14 22:42 ` threading question (results after thread pooling) ognen
2001-06-14 23:00 ` Mike Castle
2001-06-12 21:58 ` threading question Albert D. Cahalan
2001-06-12 23:48 ` J . A . Magallon
2001-06-12 19:06 ` Kip Macy
2001-06-12 19:14 ` Alexander Viro
2001-06-12 19:25 ` Russell Leighton
2001-06-12 23:27 ` Mike Castle
2001-06-13 17:31 ` bert hubert
2001-06-14 6:45 ` Helge Hafting
2001-06-14 18:28 ` Alan Cox
2001-06-14 19:01 ` bert hubert
2001-06-14 19:22 ` Russell Leighton
2001-06-15 11:29 ` Anil Kumar
2001-06-14 23:05 ` J . A . Magallon
2001-06-16 14:16 ` Michael Rothwell
2001-06-16 15:19 ` Alan Cox
2001-06-16 18:33 ` Russell Leighton
2001-06-16 19:06 ` Michael Rothwell
2001-06-16 21:30 ` Coroutines [was Re: threading question] Russell Leighton
2001-06-12 22:41 ` threading question Pavel Machek
2001-06-13 19:05 Hubertus Franke
[not found] <fa.f6da6av.agod3u@ifi.uio.no>
[not found] ` <fa.e54jbkv.kg4r99@ifi.uio.no>
2001-06-16 22:22 ` Dan Maas
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