From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1759429AbYHAUD0 (ORCPT ); Fri, 1 Aug 2008 16:03:26 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1755744AbYHAUDB (ORCPT ); Fri, 1 Aug 2008 16:03:01 -0400 Received: from out01.mta.xmission.com ([166.70.13.231]:48588 "EHLO out01.mta.xmission.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1759241AbYHAUDA (ORCPT ); Fri, 1 Aug 2008 16:03:00 -0400 From: ebiederm@xmission.com (Eric W. Biederman) To: Robin Holt Cc: linux-kernel@vger.kernel.org, Pavel Emelyanov , Oleg Nesterov , Sukadev Bhattiprolu , Paul Menage , Linus Torvalds , Andrew Morton References: <20080731170022.GE9663@sgi.com> <20080731193204.GG9663@sgi.com> <20080731200835.GK9663@sgi.com> <20080801120455.GP9663@sgi.com> <20080801191336.GK10501@sgi.com> Date: Fri, 01 Aug 2008 12:59:52 -0700 In-Reply-To: <20080801191336.GK10501@sgi.com> (Robin Holt's message of "Fri, 1 Aug 2008 14:13:36 -0500") Message-ID: User-Agent: Gnus/5.110006 (No Gnus v0.6) Emacs/21.4 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii X-SA-Exim-Connect-IP: 24.130.11.59 X-SA-Exim-Mail-From: ebiederm@xmission.com X-Spam-DCC: XMission; sa01 1397; Body=1 Fuz1=1 Fuz2=1 X-Spam-Combo: ;Robin Holt X-Spam-Relay-Country: X-Spam-Report: * -1.8 ALL_TRUSTED Passed through trusted hosts only via SMTP * 0.0 T_TM2_M_HEADER_IN_MSG BODY: T_TM2_M_HEADER_IN_MSG * -0.2 BAYES_40 BODY: Bayesian spam probability is 20 to 40% * [score: 0.2289] * -0.0 DCC_CHECK_NEGATIVE Not listed in DCC * [sa01 1397; Body=1 Fuz1=1 Fuz2=1] * 0.0 XM_SPF_Neutral SPF-Neutral Subject: Re: [Patch] Scale pidhash_shift/pidhash_size up based on num_possible_cpus(). X-SA-Exim-Version: 4.2 (built Thu, 03 Mar 2005 10:44:12 +0100) X-SA-Exim-Scanned: Yes (on mgr1.xmission.com) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Robin Holt writes: > Oops, confusing details. That was a different problem we had been > tracking. Which leads back to the original question. What were you measuring that showed improvement with a larger pid hash size? Almost by definition a larger hash table will perform better. However my intuition is that we are talking about something that should be in the noise for most workloads. Eric