Re: [PATCH] to fix xtime lock for in the RT kernel patch

[George Anzinger <george@mvista.com>]

George Anzinger wrote:
> Ingo Molnar wrote:
> 
>> * George Anzinger <george@mvista.com> wrote:
>>
>>
>>> What I am suggesting is spliting the mark code so that it would only
>>> grap the offset (current TSC in most systems) during interrupt
>>> processing.  Applying this would be done later in the thread.  Since
>>> it is not applying the offset, the xtime_lock would not need to be
>>> taken.
>>
>>
>>
>> ok, you are right, and this would be fine with me. Wanna take a shot at
>> it? I've uploaded the -03 patch which is my most current tree. (with the
>> do_timer() moving done already.) I've reviewed the TSC offset codepath
>> again and i'm not sure where i got the 10 usecs from ... it's a pretty
>> cheap codepath that can be done in the direct interrupt just fine.
>>
> Tomorrow, uh, later today.  Need some sleep now...

Ingo, I have been looking at the code being proposed by John Stultz.  It looks 
like it handles all the issues I am talking about here.  I think it would be 
best to leave the RT patch as it is WRT this issue and work on getting John's 
patch ready for prime time as any work I would do here will just get tossed when 
his patch hits the steet.

Meanwhile, I will (already have) get HRT working on RT and make that available 
in the next few days.

-- 
George Anzinger   george@mvista.com
High-res-timers:  http://sourceforge.net/projects/high-res-timers/