X-Original-To: pgsql-hackers-postgresql.org@postgresql.org Received: from localhost (mx1.hub.org [200.46.208.251]) by postgresql.org (Postfix) with ESMTP id A857F9FA5B5 for ; Tue, 11 Jul 2006 10:06:52 -0300 (ADT) Received: from postgresql.org ([200.46.204.71]) by localhost (mx1.hub.org [200.46.208.251]) (amavisd-new, port 10024) with ESMTP id 45260-01 for ; Tue, 11 Jul 2006 10:06:43 -0300 (ADT) X-Greylist: from auto-whitelisted by SQLgrey- Received: from floppy.pyrenet.fr (news.pyrenet.fr [194.116.145.2]) by postgresql.org (Postfix) with ESMTP id DAAED9FA5BF for ; Tue, 11 Jul 2006 10:06:43 -0300 (ADT) Received: by floppy.pyrenet.fr (Postfix, from userid 106) id A97CB30BA0; Tue, 11 Jul 2006 15:06:41 +0200 (MET DST) From: "Qingqing Zhou" X-Newsgroups: pgsql.hackers Subject: Re: poor performance with Context Switch Storm at TPC-W. Date: Tue, 11 Jul 2006 21:06:13 +0800 Organization: Hub.Org Networking Services Lines: 22 Message-ID: References: <200607112009.FED09315.TLPPUBIBOPuVLJL@oss.ntt.co.jp> X-Complaints-To: usenet@news.hub.org X-Priority: 3 X-MSMail-Priority: Normal X-Newsreader: Microsoft Outlook Express 6.00.2800.1807 X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2800.1807 To: pgsql-hackers@postgresql.org X-Virus-Scanned: Maia Mailguard 1.0.1 X-Archive-Number: 200607/186 X-Sequence-Number: 86041 "Katsuhiko Okano" wrote > > The problem has occurred in my customer. > poor performance with Context Switch Storm occurred > with the following composition. > Usually, CS is about 5000, WIPS=360. > when CSStorm occurrence, CS is about 100000, WIPS=60 or less. > > Intel Xeon 3.0GHz*4(2CPU * H/T ON) > 4GB Memory Do you have bgwriter on and what's the parameters? I read a theory somewhere that bgwriter scan a large portion of memory and cause L1/L2 thrushing, so with HT on, the other backends sharing the physical processor with it also get thrashed ... So try to turn bgwriter off or turn HT off see what's the difference. Regards, Qingqing