From mboxrd@z Thu Jan 1 00:00:00 1970 From: David Hildenbrand Subject: Re: [PATCH RFC 0/2] assign each vcpu an owning thread and improve yielding Date: Wed, 3 Dec 2014 13:12:15 +0100 Message-ID: <20141203131215.695a3ab7@thinkpad-w530> References: <1416931449-24585-1-git-send-email-dahi@linux.vnet.ibm.com> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Cc: kvm@vger.kernel.org, gleb@kernel.org, jfrei@linux.vnet.ibm.com, borntraeger@de.ibm.com, cornelia.huck@de.ibm.com To: pbonzini@redhat.com Return-path: Received: from e06smtp15.uk.ibm.com ([195.75.94.111]:45744 "EHLO e06smtp15.uk.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751982AbaLCMMY (ORCPT ); Wed, 3 Dec 2014 07:12:24 -0500 Received: from /spool/local by e06smtp15.uk.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Wed, 3 Dec 2014 12:12:22 -0000 Received: from b06cxnps4075.portsmouth.uk.ibm.com (d06relay12.portsmouth.uk.ibm.com [9.149.109.197]) by d06dlp02.portsmouth.uk.ibm.com (Postfix) with ESMTP id 23FB72190063 for ; Wed, 3 Dec 2014 12:11:52 +0000 (GMT) Received: from d06av12.portsmouth.uk.ibm.com (d06av12.portsmouth.uk.ibm.com [9.149.37.247]) by b06cxnps4075.portsmouth.uk.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id sB3CCKtr40304708 for ; Wed, 3 Dec 2014 12:12:20 GMT Received: from d06av12.portsmouth.uk.ibm.com (localhost [127.0.0.1]) by d06av12.portsmouth.uk.ibm.com (8.14.4/8.14.4/NCO v10.0 AVout) with ESMTP id sB3CCHdc023546 for ; Wed, 3 Dec 2014 05:12:19 -0700 In-Reply-To: <1416931449-24585-1-git-send-email-dahi@linux.vnet.ibm.com> Sender: kvm-owner@vger.kernel.org List-ID: > This series improves yielding on architectures that cannot disable preemption > while entering the guest and makes the creating thread of a VCPU the owning > thread and therefore the yield target when yielding to that VCPU. > > We should focus on the case creating thread == executing thread and therefore > remove the complicated handling of PIDs involving synchronize_rcus. > > This way we can speed up the creation of VCPUs and directly yield to the > executing vcpu threads. > > Please note that - in theory - all VCPU ioctls should be triggered from the same > VCPU thread, so changing threads is not a scenario we should optimize. > > > David Hildenbrand (2): > KVM: don't check for PF_VCPU when yielding > KVM: thread creating a vcpu is the owner of that vcpu > > include/linux/kvm_host.h | 1 + > virt/kvm/kvm_main.c | 22 ++-------------------- > 2 files changed, 3 insertions(+), 20 deletions(-) > Hi Paolo, would be good if you could have a look at these patches. Thanks!