Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753199AbbDGH4k (ORCPT ); Tue, 7 Apr 2015 03:56:40 -0400 Received: from mail-wi0-f182.google.com ([209.85.212.182]:34020 "EHLO mail-wi0-f182.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752871AbbDGH4i (ORCPT ); Tue, 7 Apr 2015 03:56:38 -0400 MIME-Version: 1.0 In-Reply-To: <1428388995.3152.10.camel@gmail.com> References: <1428388995.3152.10.camel@gmail.com> From: Pengfei Yuan <0xcoolypf@gmail.com> Date: Tue, 7 Apr 2015 15:56:16 +0800 Message-ID: Subject: Re: Why not build kernel with -O3 To: Mike Galbraith Cc: linux-kernel@vger.kernel.org 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: 1313 Lines: 35 I am trying legacy GCC versions. But I am not able to try different architectures. 2015-04-07 14:43 GMT+08:00 Mike Galbraith : > On Tue, 2015-04-07 at 11:37 +0800, Pengfei Yuan wrote: >> Hi, >> >> I have conducted some experiments to compare kernels built with -O2 >> and -O3. Here are the results: >> >> Application Performance O2 Performance O3 Improvement >> Apache 127814.14 req/s 130321.24 req/s 1.96% >> Nginx 537589.08 req/s 556723.32 req/s 3.56% >> MySQL 70661.38 tx/s 71008.47 tx/s 0.49% >> PostgreSQL 79763.39 tx/s 79535.59 tx/s -0.29% >> Redis 352547.47 op/s 405417.24 op/s 15.0% >> Memcached 844439.14 op/s 845321.79 op/s 0.10% >> >> Geomean: +3.34% >> >> Experiment environment: Linux 3.19.3, GCC 4.9.3 prerelease, Core-i7 >> 4770, 32G RAM, 10GbE >> >> LMbench microbenchmark also shows reduction in various latencies, as >> well as increase of throughputs. > > Please show multiple run data for all permutations of supported gcc > version/arch ;-) > > -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/