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From: Andi Kleen <ak@suse.de>
To: john stultz <johnstul@us.ibm.com>
Cc: linux-kernel@vger.kernel.org
Subject: Re: [RFC][PATCH] linux-2.5.59_lost-tick_A0
Date: 22 Jan 2003 00:27:07 +0100	[thread overview]
Message-ID: <p731y36m6d0.fsf@oldwotan.suse.de> (raw)
In-Reply-To: john stultz's message of "22 Jan 2003 00:08:23 +0100"

john stultz <johnstul@us.ibm.com> writes:

> All,
> 	This patch addresses the following problem: Linux cannot properly
> handle the case where interrupts are disabled for longer then two ticks.

Comments:

Basic idea is good. The x86-64 2.4 tree has a similar solution for the
same problem. Especially with HZ=1000 this is really needed, because
now lost ticks are far more common than with the HZ=100 in 2.4.
I would consider some form of this patch as requirement for 2.6 release.

what happens when 1000000 does not evenly divide HZ? 
I think some ports use HZ=1024

Why is the condition > and not >= ? Eactly two ticks offset is already
one lost. In fact even >= 1.5*HZ would be dubious.

I would like to have some statistics counter somewhere in /proc for lost 
ticks, so that it can be checked for after bug reports. Perhaps even
printk for the first 5 or so.

Could you please add spaces after /* and before */

-Andi


       reply	other threads:[~2003-01-21 23:18 UTC|newest]

Thread overview: 10+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <1043189962.15683.82.camel@w-jstultz2.beaverton.ibm.com.suse.lists.linux.kernel>
2003-01-21 23:27 ` Andi Kleen [this message]
2003-01-21 23:31   ` [RFC][PATCH] linux-2.5.59_lost-tick_A0 john stultz
2003-01-21 23:48     ` Andi Kleen
2003-01-21 23:49       ` john stultz
2003-01-21 22:59 john stultz
2003-01-21 23:32 ` Andrew Morton
2003-01-21 23:48   ` john stultz
2003-01-22  5:00   ` Valdis.Kletnieks
2003-01-24 23:13 ` Stephen Hemminger
2003-01-24 23:06   ` john stultz

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