From: Peter Zijlstra <peterz@infradead.org>
To: vatsa@linux.vnet.ibm.com
Cc: Xen-devel <xen-devel@lists.xensource.com>,
Desnoyers <mathieu.desnoyers@polymtl.ca>,
"Nick Piggin" <npiggin@kernel.dk>,
"Jeremy Fitzhardinge" <jeremy@goop.org>,
Beulich <JBeulich@novell.com>,
"Linux Kernel Mailing List" <linux-kernel@vger.kernel.org>,
Fitzhardinge <jeremy.fitzhardinge@citrix.com>,
suzuki@in.ibm.com, "Avi Kivity" <avi@redhat.com>,
kvm@vger.kernel.org, "H. Peter Anvin" <hpa@zytor.com>,
"Américo Wang" <xiyou.wangcong@gmail.com>,
"Eric Dumazet" <dada1@cosmosbay.com>,
Virtualization <virtualization@lists.linux-foundation.org>
Subject: Re: [PATCH 2/3] kvm hypervisor : Add hypercalls to support pv-ticketlock
Date: Wed, 19 Jan 2011 18:50:15 +0100 [thread overview]
Message-ID: <1295459415.28776.146.camel@laptop> (raw)
In-Reply-To: <20110119172306.GA2863@linux.vnet.ibm.com>
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.
next prev parent reply other threads:[~2011-01-19 17:50 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <cover.1289940821.git.jeremy.fitzhardinge@citrix.com>
2011-01-19 16:44 ` [PATCH 00/14] PV ticket locks without expanding spinlock Srivatsa Vaddagiri
2011-01-19 17:07 ` [PATCH 1/3] debugfs: Add support to print u32 array Srivatsa Vaddagiri
2011-01-19 17:12 ` [PATCH 2/3] kvm hypervisor : Add hypercalls to support pv-ticketlock Srivatsa Vaddagiri
2011-01-19 17:21 ` Peter Zijlstra
2011-01-19 18:29 ` Srivatsa Vaddagiri
2011-01-19 18:53 ` Jeremy Fitzhardinge
2011-01-20 11:42 ` Srivatsa Vaddagiri
2011-01-20 17:49 ` Jeremy Fitzhardinge
2011-01-20 11:59 ` Srivatsa Vaddagiri
2011-01-20 13:41 ` Peter Zijlstra
2011-01-20 14:34 ` Srivatsa Vaddagiri
2011-01-20 17:56 ` Jeremy Fitzhardinge
2011-01-21 14:02 ` Srivatsa Vaddagiri
2011-01-21 14:48 ` Rik van Riel
2011-01-22 6:14 ` Srivatsa Vaddagiri
2011-01-22 14:53 ` Rik van Riel
2011-01-24 17:49 ` Jeremy Fitzhardinge
2011-01-19 17:23 ` Srivatsa Vaddagiri
2011-01-19 17:50 ` Peter Zijlstra [this message]
2011-01-19 17:17 ` [PATCH 3/3] kvm guest : Add support for pv-ticketlocks Srivatsa Vaddagiri
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