From mboxrd@z Thu Jan 1 00:00:00 1970 Path: news.gmane.org!.POSTED.blaine.gmane.org!not-for-mail From: Eli Zaretskii Newsgroups: gmane.emacs.bugs Subject: bug#31138: Native json slower than json.el Date: Tue, 23 Apr 2019 16:19:04 +0300 Message-ID: <83mukg506v.fsf@gnu.org> References: <87sh806xwa.fsf@chapu.is> <831s22gcci.fsf@gnu.org> <83y349gasn.fsf@gnu.org> <83d0lfag4x.fsf@gnu.org> <5cf45a21-65c3-67ee-f123-be83a6ee7c99@yandex.ru> <83a7gjaen6.fsf@gnu.org> <10ca4e2f-b116-16bc-c81e-24036752c867@yandex.ru> <83lg026xxb.fsf@gnu.org> <0d42dab4-6c5c-be3a-d402-f17b39e7fc3c@yandex.ru> <83k1fm6vly.fsf@gnu.org> <19b19dec-a5a0-e08d-6026-0b9621d38143@yandex.ru> <8336ma6oia.fsf@gnu.org> <83v9z657i0.fsf@gnu.org> <83o94y54ws.fsf@gnu.org> <834l6p58d1.fsf@gnu.org> <0296121e-42b9-de92-e922-adf77bca0ed9@yandex.ru> Injection-Info: blaine.gmane.org; posting-host="blaine.gmane.org:195.159.176.226"; logging-data="3444"; mail-complaints-to="usenet@blaine.gmane.org" Cc: p.stephani2@gmail.com, sebastien@chapu.is, yyoncho@gmail.com, 31138@debbugs.gnu.org To: Dmitry Gutov Original-X-From: bug-gnu-emacs-bounces+geb-bug-gnu-emacs=m.gmane.org@gnu.org Tue Apr 23 15:21:42 2019 Return-path: Envelope-to: geb-bug-gnu-emacs@m.gmane.org Original-Received: from lists.gnu.org ([209.51.188.17]) by blaine.gmane.org with esmtps (TLS1.0:RSA_AES_256_CBC_SHA1:256) (Exim 4.89) (envelope-from ) id 1hIvMg-0000RH-PO for geb-bug-gnu-emacs@m.gmane.org; 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Tue, 23 Apr 2019 09:20:02 -0400 X-Loop: help-debbugs@gnu.org Resent-From: Eli Zaretskii Original-Sender: "Debbugs-submit" Resent-CC: bug-gnu-emacs@gnu.org Resent-Date: Tue, 23 Apr 2019 13:20:02 +0000 Resent-Message-ID: Resent-Sender: help-debbugs@gnu.org X-GNU-PR-Message: followup 31138 X-GNU-PR-Package: emacs X-GNU-PR-Keywords: moreinfo Original-Received: via spool by 31138-submit@debbugs.gnu.org id=B31138.155602556127068 (code B ref 31138); Tue, 23 Apr 2019 13:20:02 +0000 Original-Received: (at 31138) by debbugs.gnu.org; 23 Apr 2019 13:19:21 +0000 Original-Received: from localhost ([127.0.0.1]:52737 helo=debbugs.gnu.org) by debbugs.gnu.org with esmtp (Exim 4.84_2) (envelope-from ) id 1hIvKT-00072V-BB for submit@debbugs.gnu.org; Tue, 23 Apr 2019 09:19:21 -0400 Original-Received: from eggs.gnu.org ([209.51.188.92]:45579) by debbugs.gnu.org with esmtp (Exim 4.84_2) (envelope-from ) id 1hIvKQ-000721-Nm for 31138@debbugs.gnu.org; Tue, 23 Apr 2019 09:19:19 -0400 Original-Received: from fencepost.gnu.org ([2001:470:142:3::e]:33085) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1hIvKJ-0003g0-M5; Tue, 23 Apr 2019 09:19:12 -0400 Original-Received: from [176.228.60.248] (port=4751 helo=home-c4e4a596f7) by fencepost.gnu.org with esmtpsa (TLS1.2:RSA_AES_256_CBC_SHA1:256) (Exim 4.82) (envelope-from ) id 1hIvKI-0002cX-Lf; Tue, 23 Apr 2019 09:19:11 -0400 In-reply-to: <0296121e-42b9-de92-e922-adf77bca0ed9@yandex.ru> (message from Dmitry Gutov on Tue, 23 Apr 2019 14:39:50 +0300) X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] X-BeenThere: debbugs-submit@debbugs.gnu.org X-Mailman-Version: 2.1.18 Precedence: list X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] X-Received-From: 209.51.188.43 X-BeenThere: bug-gnu-emacs@gnu.org List-Id: "Bug reports for GNU Emacs, the Swiss army knife of text editors" List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: bug-gnu-emacs-bounces+geb-bug-gnu-emacs=m.gmane.org@gnu.org Original-Sender: "bug-gnu-emacs" Xref: news.gmane.org gmane.emacs.bugs:158130 Archived-At: > Cc: p.stephani2@gmail.com, sebastien@chapu.is, yyoncho@gmail.com, > 31138@debbugs.gnu.org > From: Dmitry Gutov > Date: Tue, 23 Apr 2019 14:39:50 +0300 > > On 23.04.2019 13:22, Eli Zaretskii wrote: > > >>> Yes, but I'm slightly surprised why you loop from the end of the > >>> string and not from the beginning. > >> > >> To avoid creating an additional pointer variable. > > > > I don't think it matters, and looping forward is more natural and may > > even be slightly faster. > > OK. It was mostly a matter of taste for me anyway. (I would be > interested in any examples of "slightly faster", though). It's a hunch. I think modern processors and their caches deal with incrementing better than with decrementing. Maybe I'm wrong. > significant up-front cost for initializing the decoder, right? That, and the general disadvantage of going over the text twice instead of just once.