From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Delivered-To: caml-list@yquem.inria.fr Received: from concorde.inria.fr (concorde.inria.fr [192.93.2.39]) by yquem.inria.fr (Postfix) with ESMTP id 94DB8BCA8 for ; Wed, 30 Mar 2005 11:02:30 +0200 (CEST) Received: from pauillac.inria.fr (pauillac.inria.fr [128.93.11.35]) by concorde.inria.fr (8.13.0/8.13.0) with ESMTP id j2U92TAQ013546 for ; Wed, 30 Mar 2005 11:02:30 +0200 Received: from concorde.inria.fr (concorde.inria.fr [192.93.2.39]) by pauillac.inria.fr (8.7.6/8.7.3) with ESMTP id LAA24403 for ; Wed, 30 Mar 2005 11:02:29 +0200 (MET DST) Received: from mail.exomi.com (mail.exomi.com [217.169.64.72]) by concorde.inria.fr (8.13.0/8.13.0) with ESMTP id j2U92T31013539 for ; Wed, 30 Mar 2005 11:02:29 +0200 Received: from dsws (dsws.exomi.com [10.0.20.63]) by mail.exomi.com (Postfix) with ESMTP id C80435E0C; Wed, 30 Mar 2005 12:02:28 +0300 (EEST) Subject: Re: [Caml-list] 32- and 64-bit performance From: Ville-Pertti Keinonen To: Alex Baretta Cc: Jon Harrop , Ocaml In-Reply-To: <424A6632.1020902@barettadeit.com> References: <200503300340.15874.jon@ffconsultancy.com> <424A593A.5050608@barettadeit.com> <1112169658.27768.1.camel@dsws> <424A6632.1020902@barettadeit.com> Content-Type: text/plain Date: Wed, 30 Mar 2005 12:01:43 +0300 Message-Id: <1112173304.27770.22.camel@dsws> Mime-Version: 1.0 X-Mailer: Evolution 2.0.3 Content-Transfer-Encoding: 7bit X-Miltered: at concorde with ID 424A6B25.001 by Joe's j-chkmail (http://j-chkmail.ensmp.fr)! X-Miltered: at concorde with ID 424A6B25.000 by Joe's j-chkmail (http://j-chkmail.ensmp.fr)! X-Spam: no; 0.00; caml-list:01 baretta:01 compiler:01 symbolic:01 allocations:01 ocaml:01 deallocation:01 pointer:01 ...:98 wrote:01 slower:01 idiomatic:02 seems:03 seems:03 imply:03 X-Spam-Checker-Version: SpamAssassin 3.0.2 (2004-11-16) on yquem.inria.fr X-Spam-Status: No, score=0.0 required=5.0 tests=none autolearn=disabled version=3.0.2 X-Spam-Level: On Wed, 2005-03-30 at 10:41 +0200, Alex Baretta wrote: > Ah, obviously! But this seems to imply that a 32-bit machine/compiler > couple would be generally faster on symbolic processing algorithms, > which generally require a good deal of memory allocations/deallocations. > Since this is the kind of code which seems to be most idiomatic in > Ocaml, I wonder how well or how badly 64 bits will actually impact all > our software. As long as the choice is between i386 and amd64, 64-bit is probably the way to go; in Jon Harrop's benchmarks, i386 is seldom a win. Back when I got my first amd64 machine, I ran some benchmarks that were less computationally intensive, in which the differences were generally something like 10-20%. Which was faster seemed fairly random. Note that it isn't memory allocation and deallocation that is slower (on amd64, memory allocation is probably faster, since the allocation pointer is kept in a register), but programs that use fairly large amounts of memory. 32-bit vs. 64-bit might be the difference between everything fitting in L2 or not...