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Re: [Xen-devel] [PATCH 0/2] range timer support

To: "Yu, Ke" <ke.yu@xxxxxxxxx>, Dan Magenheimer <dan.magenheimer@xxxxxxxxxx>, Yu Ke <mr.yuke@xxxxxxxxx>
Subject: Re: [Xen-devel] [PATCH 0/2] range timer support
From: Keir Fraser <keir.fraser@xxxxxxxxxxxxx>
Date: Thu, 30 Oct 2008 08:35:24 +0000
Cc: "Liu, Jinsong" <jinsong.liu@xxxxxxxxx>, "Tian, Kevin" <kevin.tian@xxxxxxxxx>, "xen-devel@xxxxxxxxxxxxxxxxxxx" <xen-devel@xxxxxxxxxxxxxxxxxxx>, Dave Winchell <dwinchell@xxxxxxxxxxxxxxx>, "Wei, Gang" <gang.wei@xxxxxxxxx>
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On 30/10/08 08:31, "Yu, Ke" <ke.yu@xxxxxxxxx> wrote:

> In the range-timer-use.patch, vpt timer range is [deadline, deadline+
> MIN(period/8, 1ms)], so the tick will only expire later than expected, thus
> will not trigger the issue you mentioned. Anyway, range timer is just API,
> caller has the flexibility to decide how to use it. in the HPET case, since we
> know HPET does not allow early ticks, we can dedicatedly set range to avoid
> that.
> 
> If we increasing TIME_SLOP value, HPET ticks may expires sooner than expected.

Yeah, this is an argument for hacking in a new kind of slop for deadline
setting, or building on range timers (but keeping the existing timer
interface).

 -- Keir



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