From mboxrd@z Thu Jan 1 00:00:00 1970 From: Xiao Guangrong Subject: Re: [PATCH v2 07/16] KVM: MMU: introduce for_each_pte_list_spte Date: Sat, 21 Apr 2012 12:36:21 +0800 Message-ID: <4F923945.7030507@gmail.com> References: <4F87FA69.5060106@linux.vnet.ibm.com> <4F87FC19.8080404@linux.vnet.ibm.com> <20120414114422.e3fe6e2abbfdcce61e6f69c8@gmail.com> <4F8B93B9.2030801@linux.vnet.ibm.com> <20120417234731.a19f270d5701b11ce95d13d4@gmail.com> <4F8E3C7F.5040601@linux.vnet.ibm.com> <20120421100113.4040ac700af6d2b04dda613f@gmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Cc: Xiao Guangrong , Avi Kivity , Marcelo Tosatti , LKML , KVM To: Takuya Yoshikawa Return-path: In-Reply-To: <20120421100113.4040ac700af6d2b04dda613f@gmail.com> Sender: linux-kernel-owner@vger.kernel.org List-Id: kvm.vger.kernel.org On 04/21/2012 09:01 AM, Takuya Yoshikawa wrote: > Sorry for the delay. > > On Wed, 18 Apr 2012 12:01:03 +0800 > Xiao Guangrong wrote: > >>> I have checked dirty-log-perf myself with this patch [01-07]. >>> >>> GET_DIRTY_LOG for 1GB dirty pages has become more than 15% slower. > >> Thanks for your test! >> >> Unbelievable, i will do more test and check it more carefully. > > GET_DIRTY_LOG now traverses rmap lists intensively. > So only a small change can affect the performance when there are many > dirty pages. > >> Could you please open your tool, then i can reproduction it and find the >> real reason? > > It's already in kvm unit tests! > Great, i will check that. >> I will check whether your tool is better then kernbench/autotest after >> review your tool. > > Let's focus on "lock-less" now: so dirty-log-perf is not needed now. > > I think you failed to appeal the real advantage of your "lock-less" approach! > I will write about this on v3-threads. Thank you very much, Takuya!