Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756641Ab3H3QcG (ORCPT ); Fri, 30 Aug 2013 12:32:06 -0400 Received: from mail-ve0-f172.google.com ([209.85.128.172]:58349 "EHLO mail-ve0-f172.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756570Ab3H3QcE (ORCPT ); Fri, 30 Aug 2013 12:32:04 -0400 MIME-Version: 1.0 In-Reply-To: References: <1375758759-29629-1-git-send-email-Waiman.Long@hp.com> <1375758759-29629-2-git-send-email-Waiman.Long@hp.com> <1377751465.4028.20.camel@pasglop> <20130829070012.GC27322@gmail.com> <52200DAE.2020303@hp.com> Date: Fri, 30 Aug 2013 09:32:02 -0700 X-Google-Sender-Auth: jz0Mbe_WHdCX9jDKvErmyPD9Myk Message-ID: Subject: Re: [PATCH v7 1/4] spinlock: A new lockref structure for lockless update of refcount From: Linus Torvalds To: Sedat Dilek Cc: Waiman Long , Ingo Molnar , Benjamin Herrenschmidt , Alexander Viro , Jeff Layton , Miklos Szeredi , Ingo Molnar , Thomas Gleixner , linux-fsdevel , Linux Kernel Mailing List , Peter Zijlstra , Steven Rostedt , Andi Kleen , "Chandramouleeswaran, Aswin" , "Norton, Scott J" Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1360 Lines: 36 On Fri, Aug 30, 2013 at 8:38 AM, Sedat Dilek wrote: > > A Samsung series-5 ultrabook. > > $ grep "model name" /proc/cpuinfo | uniq > model name : Intel(R) Core(TM) i5-2467M CPU @ 1.60GHz Hmm. Do you have debugging options enabled? Because that CPU should have the same core count as mine (two+HT), a slightly smaller cache (3M vs 4M) and runs at a noticeably lower frequency (1.6GHz vs 3.5). It probably also has slower memory etc, but that should still make it maybe half speed of mine. Not 1/20th. As mentioned, I get numbers in the 65M range. Yours are under 2.7M. Even with some thermal throttling, I would expect better than that. My pixel (1.8GHz i5-3427U) should be a *bit* faster that yours. And I get 54M iterations on that. I saw you mentioned CONFIG_CMPXCHG_LOCKREF=y in your .config, so you don't have spinlock debugging enabled, but maybe you have some other expensive debug option enabled. Like DEBUG_PAGEALLOC etc. If you get "perf" compiled, mind doing a perf record -f -e cycles:pp ./a.out perf report on it and look what that says? Linus -- 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/