From mboxrd@z Thu Jan  1 00:00:00 1970
From: Gleb Natapov <gleb@redhat.com>
Subject: Re: [PATCH RFC V9 0/19] Paravirtualized ticket spinlocks
Date: Thu, 11 Jul 2013 13:11:04 +0300
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To: Raghavendra K T <raghavendra.kt@linux.vnet.ibm.com>
Cc: jeremy@goop.org, gregkh@suse.de, kvm@vger.kernel.org, linux-doc@vger.kernel.org, peterz@infradead.org, riel@redhat.com, virtualization@lists.linux-foundation.org, andi@firstfloor.org, hpa@zytor.com, stefano.stabellini@eu.citrix.com, xen-devel@lists.xensource.com, x86@kernel.org, mingo@redhat.com, habanero@linux.vnet.ibm.com, Andrew Jones <drjones@redhat.com>, konrad.wilk@oracle.com, ouyang@cs.pitt.edu, avi.kivity@gmail.com, tglx@linutronix.de, chegu_vinod@hp.com, linux-kernel@vger.kernel.org, srivatsa.vaddagiri@gmail.com, attilio.rao@citrix.com, pbonzini@redhat.com, torvalds@linux-foundation.org
List-Id: xen-devel@lists.xenproject.org

On Thu, Jul 11, 2013 at 03:40:38PM +0530, Raghavendra K T wrote:
> >>>>Gleb,
> >>>>Can you elaborate little more on what you have in mind regarding per
> >>>>VM ple_window. (maintaining part of it as a per vm variable is clear
> >>>>to
> >>>>  me), but is it that we have to load that every time of guest entry?
> >>>>
> >>>Only when it changes, shouldn't be to often no?
> >>
> >>Ok. Thinking how to do. read the register and writeback if there need
> >>to be a change during guest entry?
> >>
> >Why not do it like in the patch you've linked? When value changes write it
> >to VMCS of the current vcpu.
> >
> 
> Yes. can be done. So the running vcpu's ple_window gets updated only
> after next pl-exit. right?
I am not sure what you mean. You cannot change vcpu's ple_window while
vcpu is in a guest mode.

--
			Gleb.