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[Xen-devel] RE: [PATCH] CPUIDLE: revise tsc-save/restore to avoid big tsc skew between cpus

On Friday, December 05, 2008 10:48 PM, Keir Fraser wrote:
> On 05/12/2008 13:06, "Keir Fraser" <keir.fraser@xxxxxxxxxxxxx> wrote:
>>> Below patch should be what you expected. It will still bring continuously
>>> increasing tsc skew. If I pin all domains' vcpus on 1 pcpu, the skew is
>>> increasing faster.
>> I applied a modified version of this as c/s 18873. Primarily I removed
>> scale_time() and replaced with a simpler reciprocal function which is applied
>> to scale factors to invert them. Please take a look.
> I should have tested the reciprocal function before checkin. A fixed (and
> now rather less simple) version is in c/s 18875.

Your fix is absolutely right. Now we at least make the tsc skew increasing in a 
far slower speed. Thanks, and I will consider how to make my original patch 
work for constant_tsc case only.

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