From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Original-To: caml-list@sympa.inria.fr Delivered-To: caml-list@sympa.inria.fr Received: from mail3-relais-sop.national.inria.fr (mail3-relais-sop.national.inria.fr [192.134.164.104]) by sympa.inria.fr (Postfix) with ESMTPS id BA7F47EE51 for ; Wed, 24 Apr 2013 19:27:00 +0200 (CEST) Received-SPF: None (mail3-smtp-sop.national.inria.fr: no sender authenticity information available from domain of rixed@happyleptic.org) identity=pra; client-ip=212.27.42.5; receiver=mail3-smtp-sop.national.inria.fr; envelope-from="rixed@happyleptic.org"; x-sender="rixed@happyleptic.org"; x-conformance=sidf_compatible Received-SPF: None (mail3-smtp-sop.national.inria.fr: no sender authenticity information available from domain of rixed@happyleptic.org) identity=mailfrom; client-ip=212.27.42.5; receiver=mail3-smtp-sop.national.inria.fr; envelope-from="rixed@happyleptic.org"; x-sender="rixed@happyleptic.org"; x-conformance=sidf_compatible Received-SPF: None (mail3-smtp-sop.national.inria.fr: no sender authenticity information available from domain of postmaster@smtp5-g21.free.fr) identity=helo; client-ip=212.27.42.5; receiver=mail3-smtp-sop.national.inria.fr; envelope-from="rixed@happyleptic.org"; x-sender="postmaster@smtp5-g21.free.fr"; x-conformance=sidf_compatible X-IronPort-Anti-Spam-Filtered: true X-IronPort-Anti-Spam-Result: AvoBAAoVeFHUGyoFlGdsb2JhbABQwiCBABYOAQEBAQcNCQkUAyWCIAEFOk8LIRMSDwUoiEy+R483FoJUYQOXG5Qx X-IPAS-Result: AvoBAAoVeFHUGyoFlGdsb2JhbABQwiCBABYOAQEBAQcNCQkUAyWCIAEFOk8LIRMSDwUoiEy+R483FoJUYQOXG5Qx X-IronPort-AV: E=Sophos;i="4.87,542,1363129200"; d="scan'208";a="12094291" Received: from smtp5-g21.free.fr ([212.27.42.5]) by mail3-smtp-sop.national.inria.fr with ESMTP; 24 Apr 2013 19:26:59 +0200 Received: from shuttle.happyleptic.org (unknown [82.67.194.89]) by smtp5-g21.free.fr (Postfix) with ESMTP id 0A123D4803E for ; Wed, 24 Apr 2013 19:26:55 +0200 (CEST) Received: from rixed by shuttle.happyleptic.org with local (Exim 4.80) (envelope-from ) id 1UV3T4-0001Zy-J4 for caml-list@inria.fr; Wed, 24 Apr 2013 19:26:54 +0200 Date: Wed, 24 Apr 2013 19:26:54 +0200 From: rixed@happyleptic.org To: caml-list@inria.fr Message-ID: <20130424172654.GA5722@shuttle.happyleptic.org> References: <20130424183543.e3a4290382f7f9ce7b522a57@gmail.com> <201304241557.r3OFvT9a012995@outgoing.mit.edu> <51780360.3020607@frisch.fr> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <51780360.3020607@frisch.fr> User-Agent: Mutt/1.5.21 (2010-09-15) Subject: Re: [Caml-list] ackermann microbenchmark strange results -[ Wed, Apr 24, 2013 at 06:08:00PM +0200, Alain Frisch ]---- > +1 > > I've already seen 20% speedup obtained by adding some dead code (in > an OCaml program, but this is irrelevant). Remember me of a paper I read some years ago that was measuring the effect of the various optimisation levels of gcc against the effect of addresses choices (randomised using environment strings of various lengths!), and which conclusion was that the effect of -O3 compared to -O2 was less than the effect of "choosing" a good environment string :-) Couldn't find it again using Google ; maybe someone remember this paper?