Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751458AbWBVVBW (ORCPT ); Wed, 22 Feb 2006 16:01:22 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751462AbWBVVBW (ORCPT ); Wed, 22 Feb 2006 16:01:22 -0500 Received: from smtp.osdl.org ([65.172.181.4]:11464 "EHLO smtp.osdl.org") by vger.kernel.org with ESMTP id S1751458AbWBVVBV (ORCPT ); Wed, 22 Feb 2006 16:01:21 -0500 Date: Wed, 22 Feb 2006 12:50:49 -0800 From: Andrew Morton To: Ravikiran G Thirumalai Cc: nickpiggin@yahoo.com.au, clameter@engr.sgi.com, linux-kernel@vger.kernel.org, shai@scalex86.org Subject: Re: [patch] Cache align futex hash buckets Message-Id: <20060222125049.6386c9e1.akpm@osdl.org> In-Reply-To: <20060222201713.GA3663@localhost.localdomain> References: <20060220233242.GC3594@localhost.localdomain> <43FA8938.70006@yahoo.com.au> <43FBB2E8.2020300@yahoo.com.au> <20060221180845.79a44449.akpm@osdl.org> <43FBCE56.9020001@yahoo.com.au> <20060222201713.GA3663@localhost.localdomain> X-Mailer: Sylpheed version 1.0.4 (GTK+ 1.2.10; i386-redhat-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 677 Lines: 15 Ravikiran G Thirumalai wrote: > > We also collected hash collision statistics for 1024 slots. We found that > 50% of the slots did not take any hit!! So maybe we should revisit the > hashing function before settling on the optimal number of hash slots. You could try switching from jhash2() to hash_long(). Was there any particular pattern to the unused slots? Not something silly like every second one? - 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/