From mboxrd@z Thu Jan 1 00:00:00 1970 Path: news.gmane.io!.POSTED.blaine.gmane.org!not-for-mail From: Stefan Monnier Newsgroups: gmane.emacs.devel Subject: Re: master afc0bfd380: Speed up loaddefs-generate on slow disks Date: Thu, 02 Jun 2022 21:18:57 -0400 Message-ID: References: <165416120601.23485.9799765950267646757@vcs2.savannah.gnu.org> <20220602091326.514E9C009A8@vcs2.savannah.gnu.org> <87a6avccs4.fsf@gnus.org> <83r147dosf.fsf@gnu.org> Mime-Version: 1.0 Content-Type: text/plain Injection-Info: ciao.gmane.io; posting-host="blaine.gmane.org:116.202.254.214"; logging-data="32114"; mail-complaints-to="usenet@ciao.gmane.io" User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/29.0.50 (gnu/linux) Cc: Lars Ingebrigtsen , emacs-devel@gnu.org, eggert@cs.ucla.edu To: Eli Zaretskii Original-X-From: emacs-devel-bounces+ged-emacs-devel=m.gmane-mx.org@gnu.org Fri Jun 03 03:20:04 2022 Return-path: Envelope-to: ged-emacs-devel@m.gmane-mx.org Original-Received: from lists.gnu.org ([209.51.188.17]) by ciao.gmane.io with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.92) (envelope-from ) id 1nwvyt-0008A1-Ig for ged-emacs-devel@m.gmane-mx.org; Fri, 03 Jun 2022 03:20:03 +0200 Original-Received: from localhost ([::1]:47710 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1nwvys-0003Qv-1i for ged-emacs-devel@m.gmane-mx.org; Thu, 02 Jun 2022 21:20:02 -0400 Original-Received: from eggs.gnu.org ([2001:470:142:3::10]:41024) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1nwvxx-0002hz-VS for emacs-devel@gnu.org; Thu, 02 Jun 2022 21:19:06 -0400 Original-Received: from mailscanner.iro.umontreal.ca ([132.204.25.50]:36623) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1nwvxv-0008RC-4Z; Thu, 02 Jun 2022 21:19:04 -0400 Original-Received: from pmg3.iro.umontreal.ca (localhost [127.0.0.1]) by pmg3.iro.umontreal.ca (Proxmox) with ESMTP id 51B954425B4; Thu, 2 Jun 2022 21:19:01 -0400 (EDT) Original-Received: from mail01.iro.umontreal.ca (unknown [172.31.2.1]) by pmg3.iro.umontreal.ca (Proxmox) with ESMTP id AF44044251A; Thu, 2 Jun 2022 21:18:59 -0400 (EDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=iro.umontreal.ca; s=mail; t=1654219139; bh=XdIKxkIp/oXfLUfHRd05OigfEIPso1SSI0bU6f7aj28=; h=From:To:Cc:Subject:References:Date:In-Reply-To:From; b=efHMQUHifr/k4Q3bV8qdDOVKDwsfcqYsNEGeeJ17Z+fagdmkygH8ILzMwgjadSBQ+ dT3RQHgQnHD7OXZ0ipx3gVk+b+gIpmkDYqOQO/t+g65wVfV+EFBar96+d5o1dSP/Up uFtfkMLOB8HpQfzNVLVZQWorIK+EJtMzihM3rRzdxxtZprwjNpL/U5XP2bRB9qjJAy SZOiSoyY10Ddyky02WLJ2jpPP7WKipv52XIcygMgSlTATZDHcIcKSGjVRX9Rpp3MH3 DOsIevF+8e5FQa2yQrzLWTPnNhHDv6Jl0P1ZA/qxrdBPS97ZWaK1ponIINbSeKQfNS mRhTfS2AVbBFQ== Original-Received: from pastel (unknown [45.72.221.51]) by mail01.iro.umontreal.ca (Postfix) with ESMTPSA id 7795C120180; Thu, 2 Jun 2022 21:18:59 -0400 (EDT) In-Reply-To: <83r147dosf.fsf@gnu.org> (Eli Zaretskii's message of "Thu, 02 Jun 2022 19:16:00 +0300") Received-SPF: pass client-ip=132.204.25.50; envelope-from=monnier@iro.umontreal.ca; helo=mailscanner.iro.umontreal.ca X-Spam_score_int: -42 X-Spam_score: -4.3 X-Spam_bar: ---- X-Spam_report: (-4.3 / 5.0 requ) BAYES_00=-1.9, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, RCVD_IN_DNSWL_MED=-2.3, SPF_HELO_NONE=0.001, SPF_PASS=-0.001, T_SCC_BODY_TEXT_LINE=-0.01 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: emacs-devel@gnu.org X-Mailman-Version: 2.1.29 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-mx.org@gnu.org Original-Sender: "Emacs-devel" Xref: news.gmane.io gmane.emacs.devel:290585 Archived-At: Eli Zaretskii [2022-06-02 19:16:00] wrote: >> > I'm really surprised this is faster, even on slow disks. >> > Does anyone have a idea of why that is? > Isn't that clear? file-newer-than-file-p calls 'stat' for both files, > and one of them is a loop invariant AFAIU. Taking its time outside > the loop speeds up things (but perhaps not on GNU/Linux). Under GNU/Linux, I'd expect `stat` to be significantly faster than `file-attributes` (and the extra `stat` on the loop-invariant file should be especially fast since it should be as close as it gets w.r.t the caches (both OS-level and CPU-level)). >> I didn't actually benchmark it -- either way is fast on my laptop. But >> the old autoloads code did it with time-less-p, and Eli said that it was >> faster, so... Perhaps Eli can report back whether it made a difference >> or not. > It did -- for the better. Thanks. This suggests that the kind of change I suggested would make it even a bit faster, tho it should reduce the run time by less than 50% under Windows (because the time to do the `stat`s is apparently already >50% of the total). Stefan