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RE: [Xen-devel] [PATCH] remove HVM halt timer

To: "Keir Fraser" <Keir.Fraser@xxxxxxxxxxxx>, <xen-devel@xxxxxxxxxxxxxxxxxxx>
Subject: RE: [Xen-devel] [PATCH] remove HVM halt timer
From: "Li, Xin B" <xin.b.li@xxxxxxxxx>
Date: Fri, 10 Nov 2006 16:34:03 +0800
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Thread-topic: [Xen-devel] [PATCH] remove HVM halt timer
>
>> remove HVM halt timer.
>> It's no longer needed since interrupts can wake it up now; using
>> vcpu_unblock instead of vcpu_kick because timer callback 
>functions are
>> executed on the precossor the target vcpu is on.
>
>Why do you replace use of the schedop_block hypercall with 
>direct setting of the blocked flag and softirq?

Currently there are 3 points where vmx may gets schuduled out:
1) just before vmentry in exits.S
2) wait_on_xen_event_channel in hvm_do_resume, but I think now it's
never reachable.
3) in hvm_hlt.
Actually 3 can be merged into 1, and we can do some statistic jobs
there.
See prepare_wait_on_xen_event_channel, it's the same way.

>Also vcpu_kick() has negligible extra cost compared with vcpu_unblock()
and it's less confusing just to use it
>everywhere. Most people don't remember the semantic difference.
>

OK, I'll change back to use vcpu_kick, I also feel vcpu_unblock is
somewhat misleading .
-Xin

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