Message-ID: <4294BBE8.3030004@mvista.com>
Date: Wed, 25 May 2005 10:54:48 -0700
From: George Anzinger <george@mvista.com>
Reply-To: george@mvista.com
Organization: MontaVista Software
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To: Chris Friesen <cfriesen@nortel.com>
CC: bhavesh@avaya.com, linux-kernel@vger.kernel.org
Subject: Re: 2.6.11 timeval_to_jiffies() wrong for ms resolution timers
References: <1116975555.2050.10.camel@cof110earth.dr.avaya.com> <4294B42D.2020008@mvista.com> <4294B7ED.2030307@nortel.com>
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Chris Friesen wrote:
> George Anzinger wrote:
> 
>> Bhavesh P. Davda wrote:
>>
>>> setitimer for 20ms was firing at 21ms
> 
> 
>> If we do NOT account for this PIT issue, the result is a time drift 
>> that is outside of what ntp can handle...
> 
> 
> Still, it is non-intuitive that a multi-GHz machine can't wake you up 
> more accurately than 1ms.
> 
> What about telling it to wake up a jiffy earlier, then checking whether 
> the scheduling lag was enough to cause it to have waited the full 
> specified time.  If not, put it to sleep for another jiffy.

The user is, of course, free to do what ever they would like.  For a more 
complete solution you might be interested in HRT (High Res Timers).  See my 
signature below.
> 
-- 
George Anzinger   george@mvista.com
High-res-timers:  http://sourceforge.net/projects/high-res-timers/
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