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From: Davide Libenzi <davidel@xmailserver.org>
To: Christoph Hellwig <hch@ns.caldera.de>
Cc: linux-kernel@vger.kernel.org, ognen@gene.pbi.nrc.ca
Subject: Re: threading question
Date: Tue, 12 Jun 2001 14:44:49 -0700 (PDT)	[thread overview]
Message-ID: <XFMail.20010612144449.davidel@xmailserver.org> (raw)
In-Reply-To: <200106121858.f5CIwmX05650@ns.caldera.de>


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 ).




- Davide


  parent reply	other threads:[~2001-06-12 21:42 UTC|newest]

Thread overview: 38+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2001-06-12 18:24 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 [this message]
2001-06-12 21:48     ` ognen
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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