|
xen-devel
[Xen-devel] Re: [PATCH 2/3] kvm hypervisor : Add hypercalls to support p
|
To: |
vatsa@xxxxxxxxxxxxxxxxxx |
|
Subject: |
[Xen-devel] Re: [PATCH 2/3] kvm hypervisor : Add hypercalls to support pv-ticketlock |
|
From: |
Peter Zijlstra <peterz@xxxxxxxxxxxxx> |
|
Date: |
Wed, 19 Jan 2011 18:50:15 +0100 |
|
Cc: |
Mathieu, Xen-devel <xen-devel@xxxxxxxxxxxxxxxxxxx>, Desnoyers <mathieu.desnoyers@xxxxxxxxxx>, Nick Piggin <npiggin@xxxxxxxxx>, Jeremy, Linux, Jeremy Fitzhardinge <jeremy@xxxxxxxx>, Beulich <JBeulich@xxxxxxxxxx>, Linux Kernel Mailing List <linux-kernel@xxxxxxxxxxxxxxx>, Jan, Fitzhardinge <jeremy.fitzhardinge@xxxxxxxxxx>, suzuki@xxxxxxxxxx, Avi Kivity <avi@xxxxxxxxxx>, kvm@xxxxxxxxxxxxxxx, "H. Peter Anvin" <hpa@xxxxxxxxx>, Américo Wang <xiyou.wangcong@xxxxxxxxx>, Eric Dumazet <dada1@xxxxxxxxxxxxx>, Virtualization <virtualization@xxxxxxxxxxxxxxxxxxxxxxxxxx> |
|
Delivery-date: |
Wed, 19 Jan 2011 09:50:36 -0800 |
|
Envelope-to: |
www-data@xxxxxxxxxxxxxxxxxxx |
|
In-reply-to: |
<20110119172306.GA2863@xxxxxxxxxxxxxxxxxx> |
|
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: |
<cover.1289940821.git.jeremy.fitzhardinge@xxxxxxxxxx> <20110119164432.GA30669@xxxxxxxxxxxxxxxxxx> <20110119171239.GB726@xxxxxxxxxxxxxxxxxx> <20110119172306.GA2863@xxxxxxxxxxxxxxxxxx> |
|
Sender: |
xen-devel-bounces@xxxxxxxxxxxxxxxxxxx |
On Wed, 2011-01-19 at 22:53 +0530, Srivatsa Vaddagiri wrote:
> On Wed, Jan 19, 2011 at 10:42:39PM +0530, Srivatsa Vaddagiri wrote:
> > Add two hypercalls to KVM hypervisor to support pv-ticketlocks.
> >
> > KVM_HC_WAIT_FOR_KICK blocks the calling vcpu until another vcpu kicks it or
> > it
> > is woken up because of an event like interrupt.
>
> One possibility is to extend this hypercall to do a directed yield as well,
> which needs some more thought. Another issue that needs to be resolved with
> pv-ticketlocks is the impact on intra-VM fairness. A guest experiencing heavy
> contention can keep yielding cpu, allowing other VMs to get more time than
> they
> deserve.
No, yield sucks, if you know the owner you can do actual PI.
_______________________________________________
Xen-devel mailing list
Xen-devel@xxxxxxxxxxxxxxxxxxx
http://lists.xensource.com/xen-devel
|
|
|
Home