From mboxrd@z Thu Jan 1 00:00:00 1970 Path: news.gmane.io!.POSTED.blaine.gmane.org!not-for-mail From: Eli Zaretskii Newsgroups: gmane.emacs.bugs Subject: bug#64735: 29.0.92; find invocations are ~15x slower because of ignores Date: Mon, 24 Jul 2023 16:26:27 +0300 Message-ID: <83a5vlsanw.fsf@gnu.org> References: <1fd5e3ed-e1c3-5d6e-897f-1d5d55e379fa@gutov.dev> <87wmyupvlw.fsf@localhost> <5c4d9bea-3eb9-b262-138a-4ea0cb203436@gutov.dev> <87tttypp2e.fsf@localhost> <87r0p030w0.fsf@yahoo.com> <83sf9f6wm0.fsf@gnu.org> <83sf9eub9d.fsf@gnu.org> <2d844a34-857d-3d59-b897-73372baac480@gutov.dev> <83bkg2tsu6.fsf@gnu.org> <83bd4246-ac41-90ec-1df3-02d0bd59ca44@gutov.dev> <834jlttv1p.fsf@gnu.org> <937c3b8e-7742-91b7-c2cf-4cadd0782f0c@gutov.dev> Injection-Info: ciao.gmane.io; posting-host="blaine.gmane.org:116.202.254.214"; logging-data="35997"; mail-complaints-to="usenet@ciao.gmane.io" Cc: luangruo@yahoo.com, sbaugh@janestreet.com, yantar92@posteo.net, 64735@debbugs.gnu.org To: Dmitry Gutov Original-X-From: bug-gnu-emacs-bounces+geb-bug-gnu-emacs=m.gmane-mx.org@gnu.org Mon Jul 24 15:26:24 2023 Return-path: Envelope-to: geb-bug-gnu-emacs@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 1qNvZu-000998-Nx for geb-bug-gnu-emacs@m.gmane-mx.org; Mon, 24 Jul 2023 15:26:22 +0200 Original-Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1qNvZa-0003Sz-TV; Mon, 24 Jul 2023 09:26:02 -0400 Original-Received: from eggs.gnu.org ([2001:470:142:3::10]) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1qNvZa-0003Sr-Cn for bug-gnu-emacs@gnu.org; Mon, 24 Jul 2023 09:26:02 -0400 Original-Received: from debbugs.gnu.org ([2001:470:142:5::43]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_128_GCM_SHA256:128) (Exim 4.90_1) (envelope-from ) id 1qNvZa-0007Z2-5S for bug-gnu-emacs@gnu.org; Mon, 24 Jul 2023 09:26:02 -0400 Original-Received: from Debian-debbugs by debbugs.gnu.org with local (Exim 4.84_2) (envelope-from ) id 1qNvZZ-0007fP-Tg for bug-gnu-emacs@gnu.org; Mon, 24 Jul 2023 09:26:01 -0400 X-Loop: help-debbugs@gnu.org Resent-From: Eli Zaretskii Original-Sender: "Debbugs-submit" Resent-CC: bug-gnu-emacs@gnu.org Resent-Date: Mon, 24 Jul 2023 13:26:01 +0000 Resent-Message-ID: Resent-Sender: help-debbugs@gnu.org X-GNU-PR-Message: followup 64735 X-GNU-PR-Package: emacs Original-Received: via spool by 64735-submit@debbugs.gnu.org id=B64735.169020515529458 (code B ref 64735); Mon, 24 Jul 2023 13:26:01 +0000 Original-Received: (at 64735) by debbugs.gnu.org; 24 Jul 2023 13:25:55 +0000 Original-Received: from localhost ([127.0.0.1]:42167 helo=debbugs.gnu.org) by debbugs.gnu.org with esmtp (Exim 4.84_2) (envelope-from ) id 1qNvZS-0007f3-T2 for submit@debbugs.gnu.org; Mon, 24 Jul 2023 09:25:55 -0400 Original-Received: from eggs.gnu.org ([2001:470:142:3::10]:36468) by debbugs.gnu.org with esmtp (Exim 4.84_2) (envelope-from ) id 1qNvZQ-0007ep-Du for 64735@debbugs.gnu.org; Mon, 24 Jul 2023 09:25:53 -0400 Original-Received: from fencepost.gnu.org ([2001:470:142:3::e]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1qNvZK-0007Rn-AS; Mon, 24 Jul 2023 09:25:46 -0400 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=gnu.org; s=fencepost-gnu-org; h=References:Subject:In-Reply-To:To:From:Date: mime-version; bh=H1lJ48cWW5Ttpe9JSy1LcYxPiI0BF08jN5Bcy/d9fHA=; b=fZikmWSoqQE9 +WZLdKcjYBf+EgULAO+HnLS41hKKEcmOZEFcQcKbYHS7EEjuiMnLfW+Uy+wuLMUFXWwCW1Wnduvro m7aQfKuWESRdNpOU1Tc8ESj6EnMVFo6AqsUMpAJsscYBiou4+DPGlNa1gcRIrAsxPWOji63vR+cE9 dkbyGPFvj4F35bLZtSDdXO/p0k1oKLq2tdopJLnUuYnMymcWwRY9m1wE9nFxapYkebsS01AR1eCbS qvfT4j2IWbWothjagQ8yoF6H8PzOJyaWhAuOuOX0KfRFzKKJJokH1K/pqUbZy288s+c6sDELb35Lb mel4fn/DsWjJ5XJKeAQhqw==; Original-Received: from [87.69.77.57] (helo=home-c4e4a596f7) by fencepost.gnu.org with esmtpsa (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1qNvZJ-0007dw-BU; Mon, 24 Jul 2023 09:25:45 -0400 In-Reply-To: <937c3b8e-7742-91b7-c2cf-4cadd0782f0c@gutov.dev> (message from Dmitry Gutov on Mon, 24 Jul 2023 15:55:13 +0300) X-BeenThere: debbugs-submit@debbugs.gnu.org X-Mailman-Version: 2.1.18 Precedence: list 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-mx.org@gnu.org Original-Sender: bug-gnu-emacs-bounces+geb-bug-gnu-emacs=m.gmane-mx.org@gnu.org Xref: news.gmane.io gmane.emacs.bugs:265967 Archived-At: > Date: Mon, 24 Jul 2023 15:55:13 +0300 > Cc: luangruo@yahoo.com, sbaugh@janestreet.com, yantar92@posteo.net, > 64735@debbugs.gnu.org > From: Dmitry Gutov > > >> 1. 'find' itself is much slower there. There is room for improvement in > >> the port. > > > > I think it's the filesystem, not the port (which I did myself in this > > case). > > But directory-files-recursively goes through the same filesystem, > doesn't it? It does (more or less; see below). But I was not trying to explain why Find is slower than directory-files-recursively, I was trying to explain why Find on Windows is slower than Find on GNU/Linux. If you are asking why directory-files-recursively is so much faster on Windows than Find, then the main factors I can think about are: . IPC, at least in how we implement it in Emacs on MS-Windows, via a separate thread and OS-level events between them to signal that stuff is available for reading, whereas directory-files-recursively avoids this overhead completely; . Find uses Posix APIs: 'stat', 'chdir', 'readdir' -- which on Windows are emulated by wrappers around native APIs. Moreover, Find uses 'char *' for file names, so calling native APIs involves transparent conversion to UTF-16 and back, which is what native APIs accept and return. By contrast, Emacs on Windows calls the native APIs directly, and converts to UTF-16 from UTF-8, which is faster. (This last point also means that using Find on Windows has another grave disadvantage: it cannot fully support non-ASCII file names, only those that can be encoded by the current single-byte system codepage.) > >> 2. The process output handling is worse. > > > > Not sure what that means. > > Emacs's ability to process the output of a process on the particular > platform. > > You said: > > Btw, the Find command with pipe to some other program, like wc, > finishes much faster, like 2 to 4 times faster than when it is run > from find-directory-files-recursively. That's probably the slowdown > due to communications with async subprocesses in action. I see this slowdown on GNU/Linux as well. > One thing to try it changing the -with-find implementation to use a > synchronous call, to compare (e.g. using 'process-file'). And repeat > these tests on GNU/Linux too. This still uses pipes, albeit without the pselect stuff. > >> 3. Something particular to the project being used for the test. > > > > I don't think I understand this one. > > This described the possibility where the disparity between the > implementations' runtimes was due to something unusual in the project > structure, if you tested different projects between Windows and > GNU/Linux, making direct comparison less useful. It's the least likely > cause, but still sometimes a possibility. I have on my Windows system a d:/usr/share tree that is very similar to (albeit somewhat smaller than) a typical /usr/share tree on Posix systems. I tried with that as well, and the results were similar. > > The ezwinports is the version I'm using here. But maybe someone came > > up with a better one: after all, I did my port many years ago (because > > the native ports available back then were abysmally slow). > > We should also look at the exact numbers. If you say that "| wc" > invocation is 2-4x faster than what's reported in the benchmark, then it > takes about 2-4 seconds. Which is still oddly slower than your reported > numbers for directory-files-recursively. Yes, so there are additional factors at work, at least with this port of Find.