Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753400AbYCQFQu (ORCPT ); Mon, 17 Mar 2008 01:16:50 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751220AbYCQFQl (ORCPT ); Mon, 17 Mar 2008 01:16:41 -0400 Received: from fk-out-0910.google.com ([209.85.128.184]:44331 "EHLO fk-out-0910.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751127AbYCQFQk (ORCPT ); Mon, 17 Mar 2008 01:16:40 -0400 DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=message-id:date:from:sender:to:subject:cc:in-reply-to:mime-version:content-type:content-transfer-encoding:content-disposition:references:x-google-sender-auth; b=gHdcg7OVn/9HG9r+X8HEP42QYACCaNfjpy79oUfEbjOXSQQvPvp+r2QHGv6219t3dFpqgD2vmhxUwGZ5HZ3WIiDBVHZX8l4n4QmNYTnFALlKFXXV4tNYN68Xi062xrXTOj5Ni1w+ey3CiGiw3dwmjWoC0bmzU3M7hGa+Hci2if4= Message-ID: <2c0942db0803162216r1892782bsc894d4188b51481b@mail.gmail.com> Date: Sun, 16 Mar 2008 22:16:36 -0700 From: "Ray Lee" To: "Nick Piggin" Subject: Re: Poor PostgreSQL scaling on Linux 2.6.25-rc5 (vs 2.6.22) Cc: "Peter Zijlstra" , "Ingo Molnar" , "LKML," In-Reply-To: <200803171144.35479.nickpiggin@yahoo.com.au> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Content-Disposition: inline References: <200803111749.29143.nickpiggin@yahoo.com.au> <200803121221.37234.nickpiggin@yahoo.com.au> <1205308704.8514.197.camel@twins> <200803171144.35479.nickpiggin@yahoo.com.au> X-Google-Sender-Auth: b77929098080eaf6 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1262 Lines: 26 On Sun, Mar 16, 2008 at 5:44 PM, Nick Piggin wrote: > I don't see how it is really helpful for interactive processes either. > By definition, if they are not CPU bound, then they should be run > quite soon after waking up; if they are CPU bound, then reducing > efficiency by increasing context switches is effectively going to > increase their latency anyway. How? Are you saying that switching the granularity to, say, 25ms, will *decrease* the latency of interactive tasks? And the efficiency we're talking about reducing here is due to the fact that tasks are hitting cold caches more times per second when the granularity is smaller, correct? Or are you concerned by another issue? > Can this be changed by default, please? Not without benchmarks of interactivity, please. There are far, far more linux desktops than there are servers. People expect to have to tune servers (I do, for the servers I maintain). People don't expect to have to tune a desktop to make it run well. -- 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/