From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752647Ab2GJTlE (ORCPT ); Tue, 10 Jul 2012 15:41:04 -0400 Received: from mx1.redhat.com ([209.132.183.28]:55881 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752028Ab2GJTlB (ORCPT ); Tue, 10 Jul 2012 15:41:01 -0400 Message-ID: <4FFC853B.30900@redhat.com> Date: Tue, 10 Jul 2012 15:40:43 -0400 From: Rik van Riel User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:12.0) Gecko/20120430 Thunderbird/12.0.1 MIME-Version: 1.0 To: Raghavendra K T CC: "H. Peter Anvin" , Thomas Gleixner , Marcelo Tosatti , Ingo Molnar , Avi Kivity , S390 , Carsten Otte , Christian Borntraeger , KVM , chegu vinod , "Andrew M. Theurer" , LKML , X86 , Gleb Natapov , linux390@de.ibm.com, Srivatsa Vaddagiri , Joerg Roedel Subject: Re: [PATCH RFC V2 2/2] kvm PLE handler: Choose better candidate for directed yield References: <20120710193056.16440.40112.sendpatchset@codeblue> <20120710193138.16440.31791.sendpatchset@codeblue> In-Reply-To: <20120710193138.16440.31791.sendpatchset@codeblue> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 07/10/2012 03:31 PM, Raghavendra K T wrote: > From: Raghavendra K T > > Currently PLE handler can repeatedly do a directed yield to same vcpu > that has recently done PL exit. This can degrade the performance. > > Try to yield to most eligible guy instead by alternate yielding. > Precisely, give chance to a VCPU which has: > (a) Not done PLE exit at all (probably he is preempted lock-holder) > (b) VCPU skipped in last iteration because it did PL exit, and probably > has become eligible now (next eligible lock holder) > > Signed-off-by: Raghavendra K T Reviewed-by: Rik van Riel -- All rights reversed