From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754616Ab1JaISi (ORCPT ); Mon, 31 Oct 2011 04:18:38 -0400 Received: from smtprelay0126.b.hostedemail.com ([64.98.42.126]:55257 "EHLO smtprelay.b.hostedemail.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1754349Ab1JaISh (ORCPT ); Mon, 31 Oct 2011 04:18:37 -0400 X-Panda: scanned! X-Spam-Summary: 2,-1.05263,0,6fe00441d0454d08,d41d8cd98f00b204,t.artem@lycos.com,yong.zhang0@gmail.com:arjan@infradead.org:linux-kernel@vger.kernel.org:mingo@elte.hu:peterz@infradead.org,RULES_HIT:152:355:379:541:582:599:601:967:973:988:989:1152:1260:1277:1311:1313:1314:1345:1373:1437:1515:1516:1518:1534:1540:1593:1594:1676:1711:1730:1747:1766:1792:2194:2199:2393:2525:2560:2563:2682:2685:2693:2857:2859:2933:2937:2939:2942:2945:2947:2951:2954:3022:3027:3138:3352:3865:3866:3867:3869:3870:3871:3872:3873:3874:3934:3936:3938:3941:3944:3947:3950:3953:3956:3959:4250:5007:6117:6261:7679:7901:9025:9108:10004:10016:10394:10400:11658:11914,0,RBL:none,CacheIP:none,Bayesian:0.5,0.5,0.5,Netcheck:none,DomainCache:0,MSF:not bulk,SPF:fn,MSBL:none,DNSBL:none,Custom_rules:0:0:0 X-Session-Marker: 742E617274656D406C79636F732E636F6D X-Filterd-Recvd-Size: 1891 Date: Mon, 31 Oct 2011 08:18:35 +0000 (GMT) From: "Artem S. Tashkinov" To: yong.zhang0@gmail.com Cc: arjan@infradead.org, linux-kernel@vger.kernel.org, mingo@elte.hu, peterz@infradead.org Message-ID: <1963557866.68748.1320049115504.JavaMail.mail@webmail05> References: <269467866.49093.1320004632156.JavaMail.mail@webmail17> <20111030151256.27b2b20e@infradead.org> <1179048211.51348.1320013764432.JavaMail.mail@webmail17> <20111031031907.GB18057@zhy> Subject: Re: Re: Re: HT (Hyper Threading) aware process scheduling doesn't work as it should MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-Mailer: Webmail X-Originating-IP: [46.146.111.51] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org > > (Cc'ing more people) > > Maybe you can also show your test case here? > The test case is perfectly outlined in the first message I posted to LKML but I can repeat it for you ( https://lkml.org/lkml/2011/10/30/106 ). On a HT enabled completely idle system run as many different tasks as you have real CPU cores, e.g. on an Intel Core i7 2600 CPU, that will be four tasks. For the best performance all tasks should be attached to different physical cores. However often the opposite behaviour can be observed, the process scheduler binds pairs of tasks to virtual HT cores of the same physical CPU module, e.g. in theory you should get this distribution of tasks: 1:3:5:7 but often I get this distribution 1:6:7:8 (three physical cores loaded instead of four) or 1:2:7:8 (two physical cores loaded instead of four). Artem