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Date: Mon, 22 Apr 2013 16:50:40 -0400
From: Jiannan Ouyang <ouyang@cs.pitt.edu>
Subject: Re: Preemptable Ticket Spinlock
In-reply-to: <1366663475.8337.10.camel@laptop>
To: Peter Zijlstra <peterz@infradead.org>
Cc: Rik van Riel <riel@redhat.com>, LKML <linux-kernel@vger.kernel.org>,
        Raghavendra K T <raghavendra.kt@linux.vnet.ibm.com>,
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On Mon, Apr 22, 2013 at 4:44 PM, Peter Zijlstra <peterz@infradead.org> wrote:
> On Mon, 2013-04-22 at 16:32 -0400, Rik van Riel wrote:
>>
>> IIRC one of the reasons was that the performance improvement wasn't
>> as obvious.  Rescheduling VCPUs takes a fair amount of time, quite
>> probably more than the typical hold time of a spinlock.
>
> IIRC it would spin for a while before blocking..
>
> /me goes re-read some of that thread...
>
> Ah, its because PLE is curing most of it.. !PLE it had huge gains but
> apparently nobody cares about !PLE hardware anymore :-)
>

For now, I don't know how good it can work with PLE. But I think it
should save the time of VMEXIT on PLE machine.
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