From: Srivatsa Vaddagiri <vatsa@in.ibm.com>
To: Peter Zijlstra <peterz@infradead.org>
Cc: Avi Kivity <avi@redhat.com>,
Srivatsa Vaddagiri <vatsa.ml@gmail.com>,
"Zhang, Xiantao" <xiantao.zhang@intel.com>,
"kvm@vger.kernel.org" <kvm@vger.kernel.org>,
Marcelo Tosatti <mtosatti@redhat.com>,
"Yang, Xiaowei" <xiaowei.yang@intel.com>,
"Dong, Eddie" <eddie.dong@intel.com>,
"Li, Xin" <xin.li@intel.com>, Ingo Molnar <mingo@elte.hu>,
Mike Galbraith <efault@gmx.de>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
Subject: Re: VM performance issue in KVM guests.
Date: Thu, 15 Apr 2010 09:43:13 -0700 [thread overview]
Message-ID: <20100415164313.GF9128@linux.vnet.ibm.com> (raw)
In-Reply-To: <1271338398.1674.13.camel@laptop>
On Thu, Apr 15, 2010 at 03:33:18PM +0200, Peter Zijlstra wrote:
> On Thu, 2010-04-15 at 11:18 +0300, Avi Kivity wrote:
> >
> > Certainly that has even greater potential for Linux guests. Note that
> > we spin on mutexes now, so we need to prevent preemption while the lock
> > owner is running.
>
> either that, or disable spinning on (para) virt kernels. Para virt
> kernels could possibly extend the thing by also checking to see if the
> owner's vcpu is running.
I suspect we will need a combination of both approaches, given that we will not
be able to avoid preempting guests in their critical section always (too long
critical sections or real-time tasks wanting to preempt). Other idea is to
gang-schedule VCPUs of the same guest as much as possible?
- vatsa
next prev parent reply other threads:[~2010-04-15 16:43 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-04-10 8:16 VM performance issue in KVM guests Zhang, Xiantao
2010-04-10 19:27 ` Avi Kivity
2010-04-12 2:04 ` Zhang, Xiantao
2010-04-12 6:40 ` Avi Kivity
2010-04-13 0:50 ` Zhang, Xiantao
2010-04-13 6:46 ` Avi Kivity
2010-04-14 3:24 ` Zhang, Xiantao
2010-04-14 8:14 ` Avi Kivity
2010-04-16 2:27 ` Zhang, Xiantao
2010-04-17 19:02 ` Avi Kivity
[not found] ` <p2o2eae271004142158xaa5da968ueff0c2afe6894f9d@mail.gmail.com>
2010-04-15 8:18 ` Avi Kivity
2010-04-15 13:33 ` Peter Zijlstra
2010-04-15 16:43 ` Srivatsa Vaddagiri [this message]
2010-04-16 10:40 ` Peter Zijlstra
2010-04-19 1:32 ` Zhang, Xiantao
2010-04-17 19:04 ` Avi Kivity
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