Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1760042AbZJMOmv (ORCPT ); Tue, 13 Oct 2009 10:42:51 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1753156AbZJMOmu (ORCPT ); Tue, 13 Oct 2009 10:42:50 -0400 Received: from mail.gmx.net ([213.165.64.20]:59061 "HELO mail.gmx.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with SMTP id S1753526AbZJMOmt (ORCPT ); Tue, 13 Oct 2009 10:42:49 -0400 X-Authenticated: #14349625 X-Provags-ID: V01U2FsdGVkX18qkYxT904q0V/YwfVlWdT7RVJke06sG97plqz28p FfTHeFRpdCPY1K Subject: Re: [patch] perf_counter tools: remove expensive old debug code from perf top From: Mike Galbraith To: Ingo Molnar Cc: Arnaldo Carvalho de Melo , =?ISO-8859-1?Q?Fr=E9d=E9ric?= Weisbecker , LKML , Peter Zijlstra In-Reply-To: <20091013133707.GA21409@elte.hu> References: <1255438640.7173.1.camel@marge.simson.net> <20091013133707.GA21409@elte.hu> Content-Type: text/plain Date: Tue, 13 Oct 2009 16:41:59 +0200 Message-Id: <1255444919.7042.2.camel@marge.simson.net> Mime-Version: 1.0 X-Mailer: Evolution 2.24.1.1 Content-Transfer-Encoding: 7bit X-Y-GMX-Trusted: 0 X-FuHaFi: 0.57 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1625 Lines: 42 On Tue, 2009-10-13 at 15:37 +0200, Ingo Molnar wrote: > * Mike Galbraith wrote: > > > perf_counter tools: remove expensive old debug code from perf top > > > > Calling gettimeofday() at high frequency is painful for handicapped > > boxen. The spot calling gettimeofday() is old unneeded debug code, so > > remove it. > > Thanks! > > We still seem to have a performance problem. Just running perf top on a > 16-way box: > > Performance counter stats for 'perf top -e cycles -c 3000000': > > 585.694831 task-clock-msecs # 0.113 CPUs > 35163 context-switches # 0.060 M/sec > 17 CPU-migrations # 0.000 M/sec > 20355 page-faults # 0.035 M/sec > 1476952962 cycles # 2521.711 M/sec > 730770658 instructions # 0.495 IPC > 11489471 cache-references # 19.617 M/sec > 2055001 cache-misses # 3.509 M/sec > > 5.169518576 seconds time elapsed > > that's 11% of CPU time used on a single CPU - just displaying a measly > 16K irqs/sec. Something's not quite right here. I'll try to figure out why after I do some more wakeup preempt testing. btw, something broke top annotation (again). Module symbols still annotate, but vmlinux symbols went south. -Mike -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/