Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S934260Ab1CXUmS (ORCPT ); Thu, 24 Mar 2011 16:42:18 -0400 Received: from mga03.intel.com ([143.182.124.21]:38669 "EHLO mga03.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933787Ab1CXUmP (ORCPT ); Thu, 24 Mar 2011 16:42:15 -0400 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="4.63,239,1299484800"; d="scan'208";a="408196459" From: Andi Kleen To: Ingo Molnar Cc: Jack Steiner , Jan Beulich , Borislav Petkov , Peter Zijlstra , Nick Piggin , "x86\@kernel.org" , Thomas Gleixner , Andrew Morton , Linus Torvalds , Ingo Molnar , tee@sgi.com, Nikanth Karthikesan , "linux-kernel\@vger.kernel.org" , "H. Peter Anvin" Subject: Re: [PATCH RFC] x86: avoid atomic operation in test_and_set_bit_lock if possible References: <201103241026.01624.knikanth@suse.de> <20110324085647.GI30812@elte.hu> <20110324145221.GC31194@aftab> <4D8B83DA02000078000381DE@vpn.id2.novell.com> <20110324173020.GA26761@sgi.com> <20110324200010.GB7957@elte.hu> Date: Thu, 24 Mar 2011 13:40:49 -0700 In-Reply-To: <20110324200010.GB7957@elte.hu> (Ingo Molnar's message of "Thu, 24 Mar 2011 21:00:10 +0100") Message-ID: User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/23.2 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 916 Lines: 25 Ingo Molnar writes: > > One good way to see cache bounces is to run a misses/accesses ratio profile: > > perf top -e cache-misses -e cache-references --count-filter 10 > > Note the two events: this runs a 'weighted' profile, you'll see (LLC) > cache-misses of a function relative to cache-references it does, a > misses/references ratio in essence. If anyone does this on a Nehalem please only use 2.6.39-rc*+ which includes the offcore patches. Anything before that will get you complete bogus numbers. BTW with Lin-Ming's memory latency profiling code you can do this much more directly. -Andi -- ak@linux.intel.com -- Speaking for myself only -- 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/