Re: [PATCH] Re: itimer oddness in 2.6.12

From: Bill Davidsen
Date: Mon Jul 25 2005 - 14:04:14 EST

George Anzinger wrote:
Tom Marshall wrote:

On Fri, Jul 22, 2005 at 08:21:25PM +0100, Paulo Marques wrote:

Tom Marshall wrote:

The patch to fix "setitimer timer expires too early" is causing issues for
the Helix server. We have a timer processs that updates the server's
timestamp on an itimer and it expects the signal to be delivered at roughly
the interval retrieved from getitimer. This is very consistent on every
platform, including Linux up to 2.6.11, but breaks on 2.6.12. On 2.6.12,
setting the itimer to 10ms and retrieving the actual interval from getitimer
reports 10.998ms, but the timer interrupts are consistently delivered at
roughly 11.998ms.

Unfortunately, this is not so clear cut as it seems :(

Oops! That patch is wrong. The +1 should be applied to the initial interval _only_. We KNOW when the repeating intervals start (i.e. at the jiffie edge) and don't need to adjust them. The patch, however, incorrectly, rolls them all into one. The attach patch should fix the problem. Warnning, it compiles and boots, but I have not tested it.

Can this get into 2.6.13? Or stable if it's too late? This would appear to be a fix to a visible problem.

-bill davidsen (davidsen@xxxxxxx)
"The secret to procrastination is to put things off until the
last possible moment - but no longer" -me

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