Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754874AbYCIVcA (ORCPT ); Sun, 9 Mar 2008 17:32:00 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1753224AbYCIVbw (ORCPT ); Sun, 9 Mar 2008 17:31:52 -0400 Received: from smtp-out01.alice-dsl.net ([88.44.60.11]:6165 "EHLO smtp-out01.alice-dsl.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753009AbYCIVbw (ORCPT ); Sun, 9 Mar 2008 17:31:52 -0400 To: Alexander van Heukelum Cc: Thomas Gleixner , Ingo Molnar , "H. Peter Anvin" , LKML , heukelum@fastmail.fm Subject: Re: [PATCH] x86: Change x86 to use generic find_next_bit References: <20080309200103.GA895@mailshack.com> From: Andi Kleen Date: 09 Mar 2008 22:31:49 +0100 In-Reply-To: <20080309200103.GA895@mailshack.com> Message-ID: <87myp7zire.fsf@basil.nowhere.org> User-Agent: Gnus/5.09 (Gnus v5.9.0) Emacs/21.3 MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii X-OriginalArrivalTime: 09 Mar 2008 21:25:18.0715 (UTC) FILETIME=[12E3CCB0:01C8822C] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 852 Lines: 16 Alexander van Heukelum writes: > > Benchmark using: gcc -fomit-frame-pointer -Os. For each bitmap size > 1...512, for each possible bitmap with one bit set, for each possible > offset: find the position of the first bit starting at offset. If you > follow ;). Times include setup of the bitmap and checking of the > results. BTW another comment: it would be far more sense if you did some profiling on what bitmap sizes a real kernel uses (should be easy enough with some systemtap) and benchmarked only that. I doubt 1 bit bitmap searches are common for example ... -Andi -- 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/