From mboxrd@z Thu Jan 1 00:00:00 1970 Path: news.gmane.org!.POSTED!not-for-mail From: Andreas Politz 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 17:38:09 +0100 Message-ID: <8737e1fh1q.fsf@luca> References: <77900613-3b45-52f4-5770-38fe6f27e69c@gmail.com> <83vaqxbzub.fsf@gnu.org> <8760ixhc9a.fsf@luca> <96d5bde3-fc20-750e-abc7-541b2abd2bd8@gmail.com> NNTP-Posting-Host: blaine.gmane.org Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable X-Trace: blaine.gmane.org 1490459952 10413 195.159.176.226 (25 Mar 2017 16:39:12 GMT) X-Complaints-To: usenet@blaine.gmane.org NNTP-Posting-Date: Sat, 25 Mar 2017 16:39:12 +0000 (UTC) User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/26.0.50 (gnu/linux) Cc: Eli Zaretskii , emacs-devel@gnu.org To: =?utf-8?Q?Cl=C3=A9ment?= Pit-Claudel Original-X-From: emacs-devel-bounces+ged-emacs-devel=m.gmane.org@gnu.org Sat Mar 25 17:39:08 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 1croiT-0001tR-N5 for ged-emacs-devel@m.gmane.org; Sat, 25 Mar 2017 17:39:01 +0100 Original-Received: from localhost ([::1]:37965 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1croiZ-0002ue-I9 for ged-emacs-devel@m.gmane.org; Sat, 25 Mar 2017 12:39:07 -0400 Original-Received: from eggs.gnu.org ([2001:4830:134:3::10]:52781) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1crohw-0002uZ-QK for emacs-devel@gnu.org; Sat, 25 Mar 2017 12:38:29 -0400 Original-Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1crohw-00012w-4v for emacs-devel@gnu.org; Sat, 25 Mar 2017 12:38:28 -0400 Original-Received: from gateway-a.fh-trier.de ([143.93.54.181]:40039) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1crohr-0000xx-Ef; Sat, 25 Mar 2017 12:38:23 -0400 X-Virus-Scanned: by Amavisd-new + McAfee uvscan + ClamAV [Rechenzentrum Hochschule Trier (RZ/HT)] Original-Received: from localhost (ip5f5bdecf.dynamic.kabel-deutschland.de [95.91.222.207]) (using TLSv1 with cipher AES256-SHA (256/256 bits)) (No client certificate requested) (Authenticated sender: politza) by gateway-a.fh-trier.de (Postfix) with ESMTPSA id 78C74179B536; Sat, 25 Mar 2017 17:38:09 +0100 (CET) DKIM-Signature: v=1; a=rsa-sha1; c=simple/simple; d=hochschule-trier.de; s=default; t=1490459889; bh=h0zdYIja7fQkZBVwunp6ArlV2MI=; h=From:To:Cc:Subject:References:Date:Message-ID:MIME-Version: Content-Type:Content-Transfer-Encoding; b=BVzkLj3hkBO4JYd56uQ2pMRcqWBgFIsy1/pC3by88KJksKWVOo4P7FRBHxcLUAnFT wTarOFnxioSo2fGWWZ1EBnrxT8vnFP1kJ0Al3AHGxlWw7/mANZgtbfAaQTQayOOeN/ Q6LV77AI6n/Ocsq9OFNo5vVsA8tgHqZrkjKWhT/c= X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.6.x [fuzzy] X-Received-From: 143.93.54.181 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:213342 Archived-At: Cl=C3=A9ment Pit-Claudel writes: > On 2017-03-25 06:38, Andreas Politz wrote: >> The limiting factor may also be python itself... >> >> ;; python2 >> ((0.114342188 0 0.0) >> (0.715895279 0 0.0) >> (2.120252213 0 0.0) >> (1.02429565 0 0.0)) >> >> ;; bash =3D "while read;do : ;done" >> ((2.008305836 0 0.0) >> (1.999825023 0 0.0) >> (2.026715753 0 0.0) >> (2.060320318 0 0.0)) > > Interesting! But doesn't this just show that bash is uniformly slow? This suggests to me, that the deciding factor in these numbers is python and not Emacs. Maybe it has a read buffer of a certain size, let's say 65536 ;O), and if that buffer runs out of space, things get stalled. -ap