|
xen-devel
[Xen-devel] Re: [PATCH RFC V2 3/5] kvm hypervisor : Add two hypercalls t
|
To: |
Avi Kivity <avi@xxxxxxxxxx> |
|
Subject: |
[Xen-devel] Re: [PATCH RFC V2 3/5] kvm hypervisor : Add two hypercalls to support pv-ticketlock |
|
From: |
Jeremy Fitzhardinge <jeremy@xxxxxxxx> |
|
Date: |
Wed, 26 Oct 2011 13:09:48 -0700 |
|
Cc: |
Raghavendra K T <raghukt@xxxxxxxxxxxxxxxxxx>, Raghavendra K T <raghavendra.kt@xxxxxxxxxxxxxxxxxx>, KVM <kvm@xxxxxxxxxxxxxxx>, Peter Zijlstra <peterz@xxxxxxxxxxxxx>, Srivatsa Vaddagiri <vatsa@xxxxxxxxxxxxxxxxxx>, "H. Peter Anvin" <hpa@xxxxxxxxx>, Jeremy Fitzhardinge <jeremy.fitzhardinge@xxxxxxxxxx>, Dave Jiang <dave.jiang@xxxxxxxxx>, Gleb Natapov <gleb@xxxxxxxxxx>, x86@xxxxxxxxxx, Ingo Molnar <mingo@xxxxxxxxxx>, Stefano Stabellini <stefano.stabellini@xxxxxxxxxxxxx>, Marcelo Tosatti <mtosatti@xxxxxxxxxx>, Xen <xen-devel@xxxxxxxxxxxxxxxxxxx>, Sedat Dilek <sedat.dilek@xxxxxxxxx>, Thomas Gleixner <tglx@xxxxxxxxxxxxx>, Virtualization <virtualization@xxxxxxxxxxxxxxxxxxxxxxxxxx>, Yinghai Lu <yinghai@xxxxxxxxxx>, Konrad Rzeszutek Wilk <konrad.wilk@xxxxxxxxxx>, Greg Kroah-Hartman <gregkh@xxxxxxx>, LKML <linux-kernel@xxxxxxxxxxxxxxx>, Suzuki Poulose <suzuki@xxxxxxxxxxxxxxxxxx> |
|
Delivery-date: |
Thu, 27 Oct 2011 05:10:26 -0700 |
|
Envelope-to: |
www-data@xxxxxxxxxxxxxxxxxxx |
|
In-reply-to: |
<4EA7E21B.8020805@xxxxxxxxxx> |
|
List-help: |
<mailto:xen-devel-request@lists.xensource.com?subject=help> |
|
List-id: |
Xen developer discussion <xen-devel.lists.xensource.com> |
|
List-post: |
<mailto:xen-devel@lists.xensource.com> |
|
List-subscribe: |
<http://lists.xensource.com/mailman/listinfo/xen-devel>, <mailto:xen-devel-request@lists.xensource.com?subject=subscribe> |
|
List-unsubscribe: |
<http://lists.xensource.com/mailman/listinfo/xen-devel>, <mailto:xen-devel-request@lists.xensource.com?subject=unsubscribe> |
|
References: |
<20111023190307.16364.35381.sendpatchset@xxxxxxxxxxxxxxxxxxxx> <20111023190558.16364.2136.sendpatchset@xxxxxxxxxxxxxxxxxxxx> <4EA53A7D.300@xxxxxxxxxx> <20111024122734.GA10634@xxxxxxxxxxxxxxxxxx> <4EA56385.9040302@xxxxxxxxxx> <20111024135032.GB10634@xxxxxxxxxxxxxxxxxx> <4EA6FEC2.1060209@xxxxxxxxxxxxxxxxxx> <4EA7E21B.8020805@xxxxxxxxxx> |
|
Sender: |
xen-devel-bounces@xxxxxxxxxxxxxxxxxxx |
|
User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:7.0.1) Gecko/20110930 Thunderbird/7.0.1 |
On 10/26/2011 03:34 AM, Avi Kivity wrote:
> On 10/25/2011 08:24 PM, Raghavendra K T wrote:
>> So then do also you foresee the need for directed yield at some point,
>> to address LHP? provided we have good improvements to prove.
> Doesn't this patchset completely eliminate lock holder preemption?
Well, there's the question of whether its better for someone waiting for
a contended lock to just go to sleep and rely on the scheduler to give
CPU time to whoever currently has the lock, or if the scheduler needs a
little hint to boost the lock holder by giving it the waiter's timeslice.
I tend to prefer the former, since there's no reason to suppose that the
the lock holder vcpu is necessarily the scheduler's top priority, and it
may want to schedule something else anyway.
J
_______________________________________________
Xen-devel mailing list
Xen-devel@xxxxxxxxxxxxxxxxxxx
http://lists.xensource.com/xen-devel
|
|
|
Home