From mboxrd@z Thu Jan 1 00:00:00 1970 Path: news.gmane.org!.POSTED!not-for-mail From: =?UTF-8?Q?Cl=c3=a9ment_Pit-Claudel?= Newsgroups: gmane.emacs.devel Subject: Re: Why does adding a useless copy-sequence and discarding the result make my ELisp 40 times faster? Date: Sat, 25 Mar 2017 00:24:20 -0400 Message-ID: <77900613-3b45-52f4-5770-38fe6f27e69c@gmail.com> References: NNTP-Posting-Host: blaine.gmane.org Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 8bit X-Trace: blaine.gmane.org 1490415876 7954 195.159.176.226 (25 Mar 2017 04:24:36 GMT) X-Complaints-To: usenet@blaine.gmane.org NNTP-Posting-Date: Sat, 25 Mar 2017 04:24:36 +0000 (UTC) User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:45.0) Gecko/20100101 Thunderbird/45.8.0 To: Emacs developers Original-X-From: emacs-devel-bounces+ged-emacs-devel=m.gmane.org@gnu.org Sat Mar 25 05:24:26 2017 Return-path: Envelope-to: ged-emacs-devel@m.gmane.org Original-Received: from lists.gnu.org ([208.118.235.17]) by blaine.gmane.org with esmtp (Exim 4.84_2) (envelope-from ) id 1crdFZ-0000nl-9u for ged-emacs-devel@m.gmane.org; Sat, 25 Mar 2017 05:24:25 +0100 Original-Received: from localhost ([::1]:35898 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1crdFf-0006Ez-3W for ged-emacs-devel@m.gmane.org; Sat, 25 Mar 2017 00:24:31 -0400 Original-Received: from eggs.gnu.org ([2001:4830:134:3::10]:38122) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1crdFZ-0006Ei-KL for emacs-devel@gnu.org; Sat, 25 Mar 2017 00:24:26 -0400 Original-Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1crdFW-0007A4-GM for emacs-devel@gnu.org; Sat, 25 Mar 2017 00:24:25 -0400 Original-Received: from mail-qt0-x235.google.com ([2607:f8b0:400d:c0d::235]:36427) by eggs.gnu.org with esmtps (TLS1.0:RSA_AES_128_CBC_SHA1:16) (Exim 4.71) (envelope-from ) id 1crdFW-00079b-CL for emacs-devel@gnu.org; Sat, 25 Mar 2017 00:24:22 -0400 Original-Received: by mail-qt0-x235.google.com with SMTP id r45so5839183qte.3 for ; Fri, 24 Mar 2017 21:24:22 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=subject:to:references:from:message-id:date:user-agent:mime-version :in-reply-to:content-transfer-encoding; bh=cilIf0iwNRyfY3rtR2ItIE9EBG9MHM7zUVHzXY79lEk=; b=U+mB/4VaZa1sWlaYFQSC7shPi0LhXOWrAbxaX1Y98m/BJDEYVuEVaCVrkbicKrOL4i nc8inSDfdwCR6wycFBG3gGEt1trcTmkB11RTc5c/xJFNvvnaJEGnXc+0m4H+BpCrb2C5 ICibuwIiFy2omIPJA78MyX19AG2JiWJ09KGVrQgBPjoi8CdsUx/Uk9/vn72czEi3Yf0a n8xkXfU3VXq+b00mLHaYJMmQjqvcPbwCJOUcwLqN8G0lNjGIdWGIjXJk4hg64PpM3JgO fkfREsGUpSMQ4Yerw9KERCwfBv2Q8RHPfdjpj3s3iGdrTR+Q5xGt3pogo3/kBCFxBO70 cTvg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:subject:to:references:from:message-id:date :user-agent:mime-version:in-reply-to:content-transfer-encoding; bh=cilIf0iwNRyfY3rtR2ItIE9EBG9MHM7zUVHzXY79lEk=; b=ZIcGHh4PPfYUmkADqEf4YaIqdE9cLj5dHsN2Lk2KToV2lTdNXyo/WL+s0vqd/J4Zj3 Msv5+RBt/S2OX50qJJPz2oi1+RtOsSKcX9V3t8Adomx8lt0zMNWdQFyQW8vIzMg3+MgY rnAIq9+G0E9cmB+xku2H+BOm03FGlt5mf8dmUSViO7BX/ix06Ve661MCGhSk/ZjGDWJx Q9ApbqqKddjO64g/fzjopfiRMhwb4+tewrBdI+2KCfTfbBv4R5F22fgDXfw2xSVvFK0n fzzwksApzt+iqnpy25zQdMbQjPYbg4t1WcQDPPFfxhZzdvPfat/QJ3t0NDxRfvBdyYHR XDiA== X-Gm-Message-State: AFeK/H01M+6zlxZOixRd9pDt4F1VTybiaGnGUW16sLR9+TzI5UE6KDYGxAf+BqHALVI0jA== X-Received: by 10.200.39.56 with SMTP id g53mr11882290qtg.134.1490415861728; Fri, 24 Mar 2017 21:24:21 -0700 (PDT) Original-Received: from [18.189.26.125] (dhcp-18-189-26-125.dyn.MIT.EDU. [18.189.26.125]) by smtp.gmail.com with ESMTPSA id 141sm2969402qkj.1.2017.03.24.21.24.21 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Fri, 24 Mar 2017 21:24:21 -0700 (PDT) In-Reply-To: X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] X-Received-From: 2607:f8b0:400d:c0d::235 X-BeenThere: emacs-devel@gnu.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: "Emacs development discussions." List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: emacs-devel-bounces+ged-emacs-devel=m.gmane.org@gnu.org Original-Sender: "Emacs-devel" Xref: news.gmane.org gmane.emacs.devel:213326 Archived-At: On 2017-03-25 00:06, Clément Pit-Claudel wrote: > * Why does running additional, supposedly useless code speed things up so much? (1) Interestingly, it turns out that (copy-sequence) isn't needed: instead, it's enough to use (sleep-for 0.000001) (or even (sleep-for cl-least-positive-normalized-float)) to get the 40x speedup.