From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752956AbaEVByw (ORCPT ); Wed, 21 May 2014 21:54:52 -0400 Received: from mga11.intel.com ([192.55.52.93]:25585 "EHLO mga11.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751731AbaEVByv (ORCPT ); Wed, 21 May 2014 21:54:51 -0400 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="4.98,883,1392192000"; d="scan'208";a="535769805" Date: Thu, 22 May 2014 09:54:48 +0800 From: Fengguang Wu To: Andy Lutomirski Cc: Jet Chen , "H. Peter Anvin" , LKML , lkp@01.org Subject: Re: [x86, vdso] cfda7bb9ecb: +14.7% will-it-scale.per_thread_ops Message-ID: <20140522015448.GA23196@localhost> References: <537AEF2D.9040207@intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Andy, On Wed, May 21, 2014 at 03:46:58PM -0700, Andy Lutomirski wrote: > On Mon, May 19, 2014 at 10:59 PM, Jet Chen wrote: > > Hi Andy, > > > > FYI, we noticed the below changes on > > > > git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip.git x86/vdso > > commit cfda7bb9ecbf9d96264bb5bade33a842966d1062 ("x86, vdso: Move syscall > > and sysenter setup into kernel/cpu/common.c") > > This is really strange. That change shouldn't have any effect except > that some kernels might boot a cycle or two faster. > > > > > test case: nhm4/will-it-scale/sched_yield > > > > 3d7ee969bffcc98 cfda7bb9ecbf9d96264bb5bad > > --------------- ------------------------- > > 5497021 ~ 0% +14.7% 6303424 ~ 0% TOTAL > > will-it-scale.per_thread_ops > > 0.54 ~ 0% +5.6% 0.57 ~ 0% TOTAL will-it-scale.scalability > > 6209483 ~ 0% +1.6% 6305917 ~ 0% TOTAL > > will-it-scale.per_process_ops > > 2455 ~ 5% +16.9% 2870 ~ 5% TOTAL cpuidle.C1-NHM.usage > > 8829 ~ 7% +15.2% 10169 ~10% TOTAL > > slabinfo.kmalloc-64.active_objs > > 24.13 ~12% +48.9% 35.93 ~14% TOTAL time.user_time > > 393 ~ 0% -3.0% 382 ~ 1% TOTAL time.system_time > > > > Is this a speedup or a slowdown? It's a speedup. The will-it-scale/sched_yield test case's throughput increased by +14.7% (multi-thread case) and +1.6% (multi-process case). However the CPU %user time increased more, by +48.9%. Thanks, Fengguang