From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752787Ab1LSLo1 (ORCPT ); Mon, 19 Dec 2011 06:44:27 -0500 Received: from mx1.redhat.com ([209.132.183.28]:60571 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752077Ab1LSLoZ (ORCPT ); Mon, 19 Dec 2011 06:44:25 -0500 Message-ID: <4EEF2382.4010605@redhat.com> Date: Mon, 19 Dec 2011 13:44:02 +0200 From: Avi Kivity User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:8.0) Gecko/20111115 Thunderbird/8.0 MIME-Version: 1.0 To: Ingo Molnar CC: "Nikunj A. Dadhania" , peterz@infradead.org, linux-kernel@vger.kernel.org, vatsa@linux.vnet.ibm.com, bharata@linux.vnet.ibm.com Subject: Re: [RFC PATCH 0/4] Gang scheduling in CFS References: <20111219083141.32311.9429.stgit@abhimanyu.in.ibm.com> <20111219112326.GA15090@elte.hu> In-Reply-To: <20111219112326.GA15090@elte.hu> Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 12/19/2011 01:23 PM, Ingo Molnar wrote: > What's behind this huge speedup? Does ebizzy use user-space > spinlocks perhaps? Could we do something on the user-space side > to get a similar speedup? kvm tries to detect spinlocks (by trapping repeated executions of PAUSE) and yield to a related vcpu. It's far from perfect however, and relies on the spinlock code using PAUSE. -- error compiling committee.c: too many arguments to function