From mboxrd@z Thu Jan 1 00:00:00 1970 From: Xiao Guangrong Subject: Re: [PATCH v3 0/6] Optimize vcpu->requests processing Date: Mon, 24 Sep 2012 18:19:51 +0800 Message-ID: <506033C7.5000903@linux.vnet.ibm.com> References: <1341853545-3023-1-git-send-email-avi@redhat.com> <505FF5E3.3070101@linux.vnet.ibm.com> <50602C80.1090102@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Cc: Marcelo Tosatti , kvm@vger.kernel.org To: Avi Kivity Return-path: Received: from e28smtp02.in.ibm.com ([122.248.162.2]:36808 "EHLO e28smtp02.in.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752351Ab2IXKUF (ORCPT ); Mon, 24 Sep 2012 06:20:05 -0400 Received: from /spool/local by e28smtp02.in.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Mon, 24 Sep 2012 15:50:02 +0530 Received: from d28av04.in.ibm.com (d28av04.in.ibm.com [9.184.220.66]) by d28relay03.in.ibm.com (8.13.8/8.13.8/NCO v10.0) with ESMTP id q8OAJwPB38273038 for ; Mon, 24 Sep 2012 15:49:58 +0530 Received: from d28av04.in.ibm.com (loopback [127.0.0.1]) by d28av04.in.ibm.com (8.14.4/8.13.1/NCO v10.0 AVout) with ESMTP id q8OAJtQl001944 for ; Mon, 24 Sep 2012 20:19:56 +1000 In-Reply-To: <50602C80.1090102@redhat.com> Sender: kvm-owner@vger.kernel.org List-ID: On 09/24/2012 05:48 PM, Avi Kivity wrote: > On 09/24/2012 07:55 AM, Xiao Guangrong wrote: >> On 07/10/2012 01:05 AM, Avi Kivity wrote: >>> Currently, any time a request bit is set (not too uncommon) we check all of them. >>> This patchset optimizes the process slightly by skipping over unset bits using >>> for_each_set_bit(). >>> >> >> I also notice that kvm_check_request costs lots of cpu time. What is the status >> of this patchset? >> > > I had problems getting rid of KVM_REQ_PENDING_TIMER. I'll try again. > > In what workloads did you see kvm_check_request()? > Run kernbench on guest, and use perf to sample, this function is really hot.