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From: Johannes Stezenbach <js@convergence.de>
To: Jamie Lokier <jamie@shareable.org>
Cc: Eric <eric@cisu.net>,
	linux-kernel@vger.kernel.org,
	"Stephan T. Lavavej" <stl@nuwen.net>
Subject: Re: Process Creation Speed
Date: Mon, 19 Apr 2004 14:09:57 +0200	[thread overview]
Message-ID: <20040419120957.GB3764@convergence.de> (raw)
In-Reply-To: <20040419094833.GB13007@mail.shareable.org>

Jamie Lokier wrote:
> Eric wrote:
> > > None of this answers the question which is relevant to linux-kernel:
> > > why does process creation take 7.5ms and fail to scale with CPU
> > > internal clock speed over a factor of 4 (600MHz x86 to 2.2GHz x86).
> > 
> > The reason it doesn't scale is probably because the kernel always runs at a 
> > specified speed, 100HZ which leaves 10ms(i believe?) timeslices. I would try 
> > a HZ patch and bump it up to 1000, i bet you would see a big difference then.
> 
> Hmm.  The timer speed shouldn't affect the measured speed of fork() at
> all.  It might show up if the measuring program is dependent on the
> timer in some way, though.

http://bulk.fefe.de/scalability/ has some benchmarks on the issue.
But I guess the numbers depend heavily on the server/CGI software used.

Johannes

  reply	other threads:[~2004-04-19 12:09 UTC|newest]

Thread overview: 13+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2004-04-17  2:16 Process Creation Speed Stephan T. Lavavej
2004-04-18  5:44 ` Eric
2004-04-19  0:30   ` Jamie Lokier
2004-04-19  2:15     ` Eric
2004-04-19  3:04       ` Jamie Lokier
2004-04-19  5:43         ` Eric
2004-04-19  9:48           ` Jamie Lokier
2004-04-19 12:09             ` Johannes Stezenbach [this message]
2004-04-19 12:44               ` Stephan T. Lavavej
2004-04-19 22:48                 ` David Lang
2004-04-22 13:40                 ` Jakob Oestergaard
2004-04-19 13:28               ` Jamie Lokier
     [not found] <1MFUQ-1zo-3@gated-at.bofh.it>
     [not found] ` <1MGnU-1U9-19@gated-at.bofh.it>
2004-04-19 15:43   ` Andi Kleen

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