linux-kernel.vger.kernel.org archive mirror
 help / color / mirror / Atom feed
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


  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 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

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=Pine.LNX.4.30.0106121546510.11222-100000@gene.pbi.nrc.ca \
    --to=ognen@gene.pbi.nrc.ca \
    --cc=davidel@xmailserver.org \
    --cc=linux-kernel@vger.kernel.org \
    --subject='Re: threading question' \
    /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

This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).