From: Peter Zijlstra <peterz@infradead.org>
To: vatsa@in.ibm.com
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: Fri, 16 Apr 2010 12:40:36 +0200 [thread overview]
Message-ID: <1271414436.4807.1935.camel@twins> (raw)
In-Reply-To: <20100415164313.GF9128@linux.vnet.ibm.com>
On Thu, 2010-04-15 at 09:43 -0700, Srivatsa Vaddagiri wrote:
> 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?
Except gang scheduling is a scalability nightmare waiting to happen. I
much prefer this hint thing.
next prev parent reply other threads:[~2010-04-16 10:40 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
2010-04-16 10:40 ` Peter Zijlstra [this message]
2010-04-19 1:32 ` Zhang, Xiantao
2010-04-17 19:04 ` Avi Kivity
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=1271414436.4807.1935.camel@twins \
--to=peterz@infradead.org \
--cc=avi@redhat.com \
--cc=eddie.dong@intel.com \
--cc=efault@gmx.de \
--cc=kvm@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=mingo@elte.hu \
--cc=mtosatti@redhat.com \
--cc=vatsa.ml@gmail.com \
--cc=vatsa@in.ibm.com \
--cc=xiantao.zhang@intel.com \
--cc=xiaowei.yang@intel.com \
--cc=xin.li@intel.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox