From: George Anzinger <george@mvista.com>
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
Date: Wed, 25 May 2005 10:54:48 -0700 [thread overview]
Message-ID: <4294BBE8.3030004@mvista.com> (raw)
In-Reply-To: <4294B7ED.2030307@nortel.com>
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/
next prev parent reply other threads:[~2005-05-25 17:56 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2005-05-24 22:59 2.6.11 timeval_to_jiffies() wrong for ms resolution timers Bhavesh P. Davda
2005-05-25 17:21 ` George Anzinger
2005-05-25 17:37 ` Chris Friesen
2005-05-25 17:54 ` George Anzinger [this message]
2005-05-25 18:07 ` Chris Friesen
-- strict thread matches above, loose matches on Subject: below --
2005-05-25 19:06 Davda, Bhavesh P (Bhavesh)
2005-05-25 20:02 ` George Anzinger
2005-05-25 21:41 ` Thomas Gleixner
2005-05-26 17:04 ` Olivier Croquette
2005-05-26 18:10 ` Richard B. Johnson
2005-05-26 18:19 ` Lee Revell
2005-05-26 19:24 ` George Anzinger
2005-05-26 19:32 ` Lee Revell
2005-05-25 19:16 Davda, Bhavesh P (Bhavesh)
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