From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Original-To: caml-list@yquem.inria.fr Delivered-To: caml-list@yquem.inria.fr Received: from nez-perce.inria.fr (nez-perce.inria.fr [192.93.2.78]) by yquem.inria.fr (Postfix) with ESMTP id 25FF6BB84 for ; Tue, 18 Apr 2006 14:56:55 +0200 (CEST) Received: from pauillac.inria.fr (pauillac.inria.fr [128.93.11.35]) by nez-perce.inria.fr (8.13.0/8.13.0) with ESMTP id k3ICusvM013931 for ; Tue, 18 Apr 2006 14:56:54 +0200 Received: from nez-perce.inria.fr (nez-perce.inria.fr [192.93.2.78]) by pauillac.inria.fr (8.7.6/8.7.3) with ESMTP id OAA15248 for ; Tue, 18 Apr 2006 14:56:53 +0200 (MET DST) Received: from ciao.gmane.org (main.gmane.org [80.91.229.2]) by nez-perce.inria.fr (8.13.0/8.13.0) with ESMTP id k3ICuq7I013926 (version=TLSv1/SSLv3 cipher=AES256-SHA bits=256 verify=NO) for ; Tue, 18 Apr 2006 14:56:53 +0200 Received: from list by ciao.gmane.org with local (Exim 4.43) id 1FVpl2-0005Ny-RT for caml-list@inria.fr; Tue, 18 Apr 2006 14:56:40 +0200 Received: from bas1-montreal42-1177927893.dsl.bell.ca ([70.53.192.213]) by main.gmane.org with esmtp (Gmexim 0.1 (Debian)) id 1AlnuQ-0007hv-00 for ; Tue, 18 Apr 2006 14:56:40 +0200 Received: from monnier by bas1-montreal42-1177927893.dsl.bell.ca with local (Gmexim 0.1 (Debian)) id 1AlnuQ-0007hv-00 for ; Tue, 18 Apr 2006 14:56:40 +0200 X-Injected-Via-Gmane: http://gmane.org/ To: caml-list@inria.fr From: Stefan Monnier Subject: Re: Performance of threaded interpreter on hyper-threaded CPU Date: Tue, 18 Apr 2006 08:56:25 -0400 Message-ID: <87bquzm4vq.fsf-monnier+gmane.comp.lang.caml.inria@gnu.org> References: <4444A46C.5000102@inria.fr> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii X-Complaints-To: usenet@sea.gmane.org X-Gmane-NNTP-Posting-Host: bas1-montreal42-1177927893.dsl.bell.ca User-Agent: Gnus/5.11 (Gnus v5.11) Emacs/22.0.50 (gnu/linux) Cancel-Lock: sha1:zYPn7W9D7xiDlyTLU8Yq1jnNREc= Sender: news X-Miltered: at nez-perce with ID 4444E216.000 by Joe's j-chkmail (http://j-chkmail.ensmp.fr)! X-Miltered: at nez-perce with ID 4444E215.000 by Joe's j-chkmail (http://j-chkmail.ensmp.fr)! X-Spam: no; 0.00; umontreal:01 3.56:98 suck:98 threaded:03 processors:04 processors:04 differences:05 arch:05 xeon:05 xeon:05 interpreter:06 marketing:93 comp:08 basically:09 depending:09 X-Spam-Checker-Version: SpamAssassin 3.0.3 (2005-04-27) on yquem.inria.fr X-Spam-Level: X-Spam-Status: No, score=0.0 required=5.0 tests=none autolearn=disabled version=3.0.3 > | 3.0 GHz Pentium 4, hyper-threaded | 2.62 | 3.46 | 0.75723 | > | dual 3.0 GHz Xeon, hyper-threaded | 3.36 | 2.59 | 1.2973 | > | 3.0 GHz Pentium 4, hyper-threaded | 2.51 | 6.15 | 0.40813 | > | dual 3.0 GHz Xeon, hyper-threaded | 3.32 | 3.58 | 0.92737 | > | 3.0 GHz Pentium 4, hyper-threaded | 2.37 | 4.75 | 0.49895 | > | dual 3.0 GHz Xeon, hyper-threaded | 3.91 | 3.56 | 1.0983 | "Xeon" and "Pentium 4" are marketing names that refer to two different packaging of basically the same set of processors (depending on whether it's targetted at servers or at desktops/laptops). Worse, the set of processors covered by each name is actually pretty large with some significant differences in their internal pipeline (some specifically targetted at making hyperthreading suck less). Have you tried to turn HT off and run your tests again? What OS was used? Were there other processes active at the same time? Maybe people on comp.arch can slove this puzzle, Stefan