From: bert hubert <bert.hubert@netherlabs.nl>
To: Rick Jones <rick.jones2@hp.com>
Cc: 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 23:17:20 +0100 [thread overview]
Message-ID: <20070220221719.GA16263@outpost.ds9a.nl> (raw)
In-Reply-To: <45DB6FD8.4050106@hp.com>
On Tue, Feb 20, 2007 at 02:02:00PM -0800, Rick Jones wrote:
> The slope appears to be flattening-out the farther out to the right it
> goes. Perhaps that is the length of time it takes to take all the
> requisite cache misses.
The rate of flattening out appears to correlate with the number of processes
running, even though the system is otherwise >99.5% idle during my
measurements.
With only 'gdm' running, things flatten out slowly, iow, it takes longer
delays to see recvfrom slow down. With only 1 process running (init=bash),
the graph is nearly flat.
>From this, it is probable that even an idle GNOME desktop (Ubunty Edgy Eft)
is under fierce cache pressure, enough to blow away my meagre 1MB in a
matter of milliseconds.
I'm trying to figure out which processes have the most impact, I had already
killed anything non-essential. But that still leaves 140 pids.
Bert
--
http://www.PowerDNS.com Open source, database driven DNS Software
http://netherlabs.nl Open and Closed source services
next prev parent reply other threads:[~2007-02-20 22:17 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
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 [this message]
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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