Re: [PATCH] Re: itimer oddness in 2.6.12

[Bill Davidsen <davidsen@tmr.com>]

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