From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932067AbYETQj1 (ORCPT ); Tue, 20 May 2008 12:39:27 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1755622AbYETQjM (ORCPT ); Tue, 20 May 2008 12:39:12 -0400 Received: from pilet.ens-lyon.fr ([140.77.167.16]:46409 "EHLO pilet.ens-lyon.fr" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755278AbYETQjL (ORCPT ); Tue, 20 May 2008 12:39:11 -0400 Date: Tue, 20 May 2008 18:39:12 +0200 From: Benoit Boissinot To: Soumyadip Das Mahapatra Cc: Akinobu Mita , Harvey Harrison , linux-kernel@vger.kernel.org Subject: Re: [PATCH 1/2] bitreversal program Message-ID: <20080520163912.GP7567@pirzuine> References: <1211229736.5915.86.camel@brick> <961aa3350805200513i4e02716eh79da76345718c3b2@mail.gmail.com> <40f323d00805200847t77b2d875j451d0eb9758cf9ff@mail.gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.17+20080114 (2008-01-14) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, May 20, 2008 at 05:57:37PM +0200, Soumyadip Das Mahapatra wrote: > On Tue, 20 May 2008, Benoit Boissinot wrote: >> On Tue, May 20, 2008 at 5:25 PM, Soumyadip Das Mahapatra >> wrote: >>> I know that my bitrev8() takes more instructions than that >>> of yours. But we have to think about faster access of cpu cache over that >>> of memory cache(which your bit_rev_table uses). >> >> I didn't review your patch, sorry. >> But I'm pretty sure that your patch won't be considered unless you >> provide benchmarks >> with numbers for different CPU/architecture. >> Ideally you should provide a script to test the correctness and the >> performance of your >> change that anyone could run on his computer. > > Thanks Benoit for giving me such a precious advice. But sorry, I dont > have any benchmarking system in my hand(how can i have? i am just a > student, not a professional). > So if you do me a favour and kindly do it for me, please :-) A quick benchmarking (that you should have done at least one your computer gives for 100000000 iterations): old: real 0m1.631s user 0m1.628s sys 0m0.004s new: real 0m5.553s user 0m5.540s sys 0m0.004s So I guess there's no need to discuss this further. regards, Benoit -- :wq