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Re: [Xen-devel] How to increase timer resolution?

To: Keir Fraser <keir.fraser@xxxxxxxxxxxxx>
Subject: Re: [Xen-devel] How to increase timer resolution?
From: Robert Kaiser <kaiser@xxxxxxxxxxxxxxxxxxxxxxxxxx>
Date: Sun, 14 Sep 2008 19:53:05 +0200
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On Sunday 14 September 2008 18:41:05 Keir Fraser wrote:
> The set_timer() infrastructure is not actually tick-based. With an APIC
> you'll get timer accuracy of around 100us (this figure because we service
> timer handlers up to 100us before the deadline specified to set_timer(),
> just to avoid multiple timer interrupts for close-together events). Without
> this extra fudge factor you'd get accuracy down to microsecond resolution.

Aha, the TIME_SLOP constant, right? So is it safe to simply reduce this 
to -say- 10us in  order to get a 20us resolution? Will check his out as soon 
as I have a suitable test machine.

Thanks again


Robert Kaiser                    http://wwwvs.informatik.fh-wiesbaden.de
Labor für Verteilte Systeme            kaiser@xxxxxxxxxxxxxxxxxxxxxxxxxx
FH Wiesbaden - University of Applied Sciences     tel: (+49)611-9495-294
Kurt-Schumacher-Ring 18, 65197 Wiesbaden, Germany fax: (+49)611-9495-289

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