Re: [RFC][PATCH] linux-2.5.59_lost-tick_A0

From: Andi Kleen (ak@suse.de)
Date: Tue Jan 21 2003 - 18:27:07 EST


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

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