From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pl0-f71.google.com (mail-pl0-f71.google.com [209.85.160.71]) by kanga.kvack.org (Postfix) with ESMTP id 2E4126B0253 for ; Wed, 20 Dec 2017 05:23:44 -0500 (EST) Received: by mail-pl0-f71.google.com with SMTP id 31so9276086plk.20 for ; Wed, 20 Dec 2017 02:23:44 -0800 (PST) Received: from mga01.intel.com (mga01.intel.com. [192.55.52.88]) by mx.google.com with ESMTPS id q7si12888526plk.225.2017.12.20.02.23.42 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Wed, 20 Dec 2017 02:23:43 -0800 (PST) Subject: Re: [PATCH v2 3/5] mm: enlarge NUMA counters threshold size References: <1513665566-4465-1-git-send-email-kemi.wang@intel.com> <1513665566-4465-4-git-send-email-kemi.wang@intel.com> <20171219124045.GO2787@dhcp22.suse.cz> <439918f7-e8a3-c007-496c-99535cbc4582@intel.com> <20171220101229.GJ4831@dhcp22.suse.cz> From: kemi Message-ID: <3a1f6441-30d9-6f45-af4b-efd53b01ee95@intel.com> Date: Wed, 20 Dec 2017 18:21:40 +0800 MIME-Version: 1.0 In-Reply-To: <20171220101229.GJ4831@dhcp22.suse.cz> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 8bit Sender: owner-linux-mm@kvack.org List-ID: To: Michal Hocko Cc: Greg Kroah-Hartman , Andrew Morton , Vlastimil Babka , Mel Gorman , Johannes Weiner , Christopher Lameter , YASUAKI ISHIMATSU , Andrey Ryabinin , Nikolay Borisov , Pavel Tatashin , David Rientjes , Sebastian Andrzej Siewior , Dave , Andi Kleen , Tim Chen , Jesper Dangaard Brouer , Ying Huang , Aaron Lu , Aubrey Li , Linux MM , Linux Kernel On 2017a1'12ae??20ae?JPY 18:12, Michal Hocko wrote: > On Wed 20-12-17 13:52:14, kemi wrote: >> >> >> On 2017a1'12ae??19ae?JPY 20:40, Michal Hocko wrote: >>> On Tue 19-12-17 14:39:24, Kemi Wang wrote: >>>> We have seen significant overhead in cache bouncing caused by NUMA counters >>>> update in multi-threaded page allocation. See 'commit 1d90ca897cb0 ("mm: >>>> update NUMA counter threshold size")' for more details. >>>> >>>> This patch updates NUMA counters to a fixed size of (MAX_S16 - 2) and deals >>>> with global counter update using different threshold size for node page >>>> stats. >>> >>> Again, no numbers. >> >> Compare to vanilla kernel, I don't think it has performance improvement, so >> I didn't post performance data here. >> But, if you would like to see performance gain from enlarging threshold size >> for NUMA stats (compare to the first patch), I will do that later. > > Please do. I would also like to hear _why_ all counters cannot simply > behave same. In other words why we cannot simply increase > stat_threshold? Maybe calculate_normal_threshold needs a better scaling > for larger machines. > Agree. We may consider that. But, unlike NUMA counters which do not effect system decision. We need consider very carefully when increase stat_threshold for all the counters for larger machines. BTW, this is another topic that we may discuss it in different thread. -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org