Re: [PATCH] Re: itimer oddness in 2.6.12

Bill Davidsen
2005-07-25T19:01:59Z

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@tmr.com)
"The secret to procrastination is to put things off until the
last possible moment - but no longer" -me