Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757742Ab0DPOLK (ORCPT ); Fri, 16 Apr 2010 10:11:10 -0400 Received: from mx1.redhat.com ([209.132.183.28]:16309 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757708Ab0DPOLI (ORCPT ); Fri, 16 Apr 2010 10:11:08 -0400 Subject: Re: vmalloc performance From: Steven Whitehouse To: Minchan Kim Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org, Nick Piggin In-Reply-To: <1271350270.2013.29.camel@barrios-desktop> References: <1271089672.7196.63.camel@localhost.localdomain> <1271249354.7196.66.camel@localhost.localdomain> <1271262948.2233.14.camel@barrios-desktop> <1271320388.2537.30.camel@localhost> <1271350270.2013.29.camel@barrios-desktop> Content-Type: text/plain Organization: Red Hat (UK) Ltd (Registered in England and Wales, No. 3798903) Registered office: Red Hat UK Ltd, Amberley Place, 107-111 Peascod Street, Windsor, Berkshire, SL4 ITE Date: Fri, 16 Apr 2010 15:10:56 +0100 Message-Id: <1271427056.7196.163.camel@localhost.localdomain> Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1462 Lines: 55 Hi, On Fri, 2010-04-16 at 01:51 +0900, Minchan Kim wrote: [snip] > Thanks for the explanation. It seems to be real issue. > > I tested to see effect with flush during rb tree search. > > Before I applied your patch, the time is 50300661 us. > After your patch, 11569357 us. > After my debug patch, 6104875 us. > > I tested it as changing threshold value. > > threshold time > 1000 13892809 > 500 9062110 > 200 6714172 > 100 6104875 > 50 6758316 > My results show: threshold time 100000 139309948 1000 13555878 500 10069801 200 7813667 100 18523172 50 18546256 > And perf shows smp_call_function is very low percentage. > > In my cases, 100 is best. > Looks like 200 for me. I think you meant to use the non _minmax version of proc_dointvec too? Although it doesn't make any difference for this basic test. The original reporter also has 8 cpu cores I've discovered. In his case divided by 4 cpus where as mine are divided by 2 cpus, but I think that makes no real difference in this case. I'll try and get some further test results ready shortly. Many thanks for all your efforts in tracking this down, Steve. -- 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/