From: Benjamin LaHaise <bcrl@kvack.org>
To: bert hubert <bert.hubert@netherlabs.nl>,
Evgeniy Polyakov <johnpol@2ka.mipt.ru>,
Josef Sipek <jsipek@fsl.cs.sunysb.edu>,
Andi Kleen <andi@firstfloor.org>,
netdev@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: all syscalls initially taking 4usec on a P4? Re: nonblocking UDPv4 recvfrom() taking 4usec @ 3GHz?
Date: Tue, 20 Feb 2007 14:40:40 -0500 [thread overview]
Message-ID: <20070220194040.GA18976@kvack.org> (raw)
In-Reply-To: <20070220193319.GA8800@outpost.ds9a.nl>
On Tue, Feb 20, 2007 at 08:33:20PM +0100, bert hubert wrote:
> I'm investigating this further for other system calls. It might be that my
> measurements are off, but it appears even a slight delay between calls
> incurs a large penalty.
Make sure your system is idle. Userspace bloat means that *lots* of idle
activity occurs in between timer ticks on recent distributions -- all those
widgets polling the hardware to see if something changed or needs updating
do a lot of damage to the caches. Try comparing a run under init=/bin/bash
with one while logged in to a desktop environment to see just how painful it
is.
-ben
--
"Time is of no importance, Mr. President, only life is important."
Don't Email: <dont@kvack.org>.
next prev parent reply other threads:[~2007-02-20 19:40 UTC|newest]
Thread overview: 25+ messages / expand[flat|nested] mbox.gz Atom feed top
2007-02-19 23:14 nonblocking UDPv4 recvfrom() taking 4usec @ 3GHz? bert hubert
2007-02-19 23:56 ` Stephen Hemminger
2007-02-20 8:04 ` bert hubert
2007-02-20 10:50 ` Andi Kleen
2007-02-20 16:27 ` all syscalls initially taking 4usec on a P4? " bert hubert
2007-02-20 16:41 ` Evgeniy Polyakov
2007-02-20 17:02 ` bert hubert
2007-02-20 17:11 ` Evgeniy Polyakov
2007-02-20 17:18 ` Evgeniy Polyakov
2007-02-21 11:06 ` Evgeniy Polyakov
2007-02-21 11:34 ` Andi Kleen
2007-02-20 18:42 ` Josef Sipek
2007-02-20 18:48 ` Evgeniy Polyakov
2007-02-20 19:33 ` bert hubert
2007-02-20 19:40 ` Benjamin LaHaise [this message]
2007-02-20 20:45 ` bert hubert
2007-02-20 21:02 ` Stephen Hemminger
2007-02-20 22:02 ` Rick Jones
2007-02-20 22:17 ` bert hubert
2007-02-20 22:22 ` Arjan van de Ven
2007-02-21 16:25 ` Chuck Ebbert
2007-02-20 22:46 ` Ian McDonald
2007-02-25 10:41 ` Pavel Machek
2007-02-25 17:06 ` Evgeniy Polyakov
2007-02-20 16:57 ` Eric Dumazet
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