From mboxrd@z Thu Jan 1 00:00:00 1970 From: Takuya Yoshikawa Subject: Re: [PATCH 0/4] KVM: Dirty logging optimization using rmap Date: Mon, 14 Nov 2011 19:56:19 +0900 Message-ID: <4EC0F3D3.9090907@oss.ntt.co.jp> References: <20111114182041.43570cdf.yoshikawa.takuya@oss.ntt.co.jp> <4EC0EC90.1090202@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Cc: mtosatti@redhat.com, kvm@vger.kernel.org, takuya.yoshikawa@gmail.com To: Avi Kivity Return-path: Received: from serv2.oss.ntt.co.jp ([222.151.198.100]:60094 "EHLO serv2.oss.ntt.co.jp" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754398Ab1KNKzp (ORCPT ); Mon, 14 Nov 2011 05:55:45 -0500 In-Reply-To: <4EC0EC90.1090202@redhat.com> Sender: kvm-owner@vger.kernel.org List-ID: (2011/11/14 19:25), Avi Kivity wrote: > On 11/14/2011 11:20 AM, Takuya Yoshikawa wrote: >> This is a revised version of my previous work. I hope that >> the patches are more self explanatory than before. >> > > It looks good. I'll let Marcelo (or anyone else?) review it as well > before applying. > > Do you have performance measurements? > For VGA, 30-40us became 3-5us when the display was quiet, with a enough warmed up guest. Near the criterion, the number was not different much from the original version. For live migration, I forgot the number but the result was good. But my test case was not enough to cover every pattern, so I changed the criterion to be a bit conservative. More tests may be able to find a better criterion. I am not in a hurry about this, so it is OK to add some tests before merging this. But what I did not like was holding spin lock more than 100us or so with the original version. With this version, at least, the problem should be cured some. Takuya One note: kvm-unit-tests' dirty logging test was broken for 32-bit box: compile error. I changed an "idt" to "boot_idt" and used it. I do not know kvm-unit-tests well, so I want somebody to fix that officially.