From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754169Ab3GJLpF (ORCPT ); Wed, 10 Jul 2013 07:45:05 -0400 Received: from merlin.infradead.org ([205.233.59.134]:46855 "EHLO merlin.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754095Ab3GJLpE (ORCPT ); Wed, 10 Jul 2013 07:45:04 -0400 Date: Wed, 10 Jul 2013 13:44:08 +0200 From: Peter Zijlstra To: "Yan, Zheng" Cc: linux-kernel@vger.kernel.org, mingo@elte.hu, eranian@google.com, ak@linux.intel.com Subject: Re: [PATCH] perf: Update event buffer tail when overwriting old events Message-ID: <20130710114408.GS25631@dyad.programming.kicks-ass.net> References: <1370498286-12801-1-git-send-email-zheng.z.yan@intel.com> <20130708121557.GA17211@twins.programming.kicks-ass.net> <51DD4787.7080504@intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <51DD4787.7080504@intel.com> User-Agent: Mutt/1.5.21 (2012-12-30) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Jul 10, 2013 at 07:37:43PM +0800, Yan, Zheng wrote: > On 07/08/2013 08:15 PM, Peter Zijlstra wrote: > > On Thu, Jun 06, 2013 at 01:58:06PM +0800, Yan, Zheng wrote: > >> From: "Yan, Zheng" > >> before overwrite mode after overwrite mode > >> AVG 1000 999 1046 1044 > >> STDEV 19.4 19.5 17.1 17.9 > > > > OK, so I was sure I replied to this email; but apparently I didn't :/ > > > > So its still adding about 5% overhead to the regular case; this is sad. > > > > What does something like the below do? > > > > I re-test the patch on a different 32 core sandybridge-ep machine. the result is quite good. > > origin origin overwrite modified modified overwrite > AVG 1000 1044 960 1006 > STDEV 39.0 26.0 28.1 14.4 Nice! -- you did fix the snafu for the overwrite more before testing right?