From: P@draigBrady.com
To: Liangchen Zheng <zlc@dream.eng.uci.edu>
Cc: linux-kernel@vger.kernel.org
Subject: Re: The values of gettimeofday() jumps.
Date: Mon, 30 May 2005 10:55:17 +0100 [thread overview]
Message-ID: <429AE305.30502@draigBrady.com> (raw)
In-Reply-To: <000201c563ee$eed993d0$85a4c380@dream.eng.uci.edu>
Liangchen Zheng wrote:
> Hello,
> We have several SMP machines (Tyan Tiger MPX motherboard, 2
> AthlonMP 1900+ CPU, linux-2.4.21-20.EL). When running some time
> sensitive programs, I observed that the values of gettimeofday() jumped
> sometimes on a couple of machines (other machines are fine), from
> several hundreds milliseconds to a couple of seconds.
That sounds like what I described here:
http://lkml.org/lkml/2005/4/4/57
2 options as far as I can see.
1. Use irq affinity to bind the timer irq to a particular CPU,
while using CPU affinity to bind your process to a particular CPU.
2. Change the code to maintain a last_tsc_low for each CPU.
--
Pádraig Brady - http://www.pixelbeat.org
--
next prev parent reply other threads:[~2005-05-30 9:58 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2005-05-28 23:17 [patch 5/7] Remove duplicate file in Documentation/networking (drivers_net_wan_Kconfig) domen
2005-05-29 1:37 ` The values of gettimeofday() jumps Liangchen Zheng
2005-05-29 1:36 ` Lee Revell
2005-05-29 7:42 ` Arjan van de Ven
2005-06-02 1:18 ` Liangchen Zheng
2005-05-30 9:55 ` P [this message]
[not found] <1117332028.11397.1.camel@mindpipe>
2005-05-31 21:59 ` Liangchen Zheng
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