From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756006AbaDGSdB (ORCPT ); Mon, 7 Apr 2014 14:33:01 -0400 Received: from mga09.intel.com ([134.134.136.24]:26218 "EHLO mga09.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755537AbaDGSck (ORCPT ); Mon, 7 Apr 2014 14:32:40 -0400 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="4.97,811,1389772800"; d="scan'208";a="488704369" From: Andi Kleen To: ling.ma.program@gmail.com Cc: mingo@redhat.com, tglx@linutronix.de, hpa@zytor.com, neleai@seznam.cz, linux-kernel@vger.kernel.org, Ling Ma Subject: Re: [PATCH RFC] x86:Improve memset with general 64bit instruction References: <1396882237-27608-1-git-send-email-ling.ma@alipay.com> Date: Mon, 07 Apr 2014 09:42:27 -0700 In-Reply-To: <1396882237-27608-1-git-send-email-ling.ma@alipay.com> (ling ma program's message of "Mon, 7 Apr 2014 10:50:37 -0400") Message-ID: <877g71jdl8.fsf@tassilo.jf.intel.com> User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/24.3 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org ling.ma.program@gmail.com writes: > From: Ling Ma > > In this patch we manage to reduce miss branch prediction by > avoiding using branch instructions and force destination to be aligned > with general 64bit instruction. > Below compared results shows we improve performance up to 1.8x > (We modified test suit from Ondra, send after this patch) You didn't specify the CPU? I assume it's some Atom, as nothing else uses these open coded functions anymore? -Andi -- ak@linux.intel.com -- Speaking for myself only