From mboxrd@z Thu Jan 1 00:00:00 1970 Path: news.gmane.io!.POSTED.blaine.gmane.org!not-for-mail From: Ihor Radchenko Newsgroups: gmane.emacs.bugs Subject: bug#66117: 30.0.50; `find-buffer-visiting' is slow when opening large number of buffers Date: Tue, 26 Sep 2023 08:54:54 +0000 Message-ID: <87o7hp9uw1.fsf@localhost> References: <878r919qfh.fsf@localhost> <72c93fb0-bf3e-3dad-69c0-2147cfa40f57@gutov.dev> <875y42xyex.fsf@localhost> <87zg1ewfc2.fsf@localhost> <834jjm749q.fsf@gnu.org> <87cyyawd1a.fsf@localhost> <83pm2a5k85.fsf@gnu.org> <87wmwh2tae.fsf@localhost> <83zg1d468w.fsf@gnu.org> <87bkdr2651.fsf@localhost> <83pm273fc1.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="33134"; mail-complaints-to="usenet@ciao.gmane.io" Cc: dmitry@gutov.dev, 66117@debbugs.gnu.org To: Eli Zaretskii Original-X-From: bug-gnu-emacs-bounces+geb-bug-gnu-emacs=m.gmane-mx.org@gnu.org Tue Sep 26 10:54:10 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 1ql3pa-0008OO-K9 for geb-bug-gnu-emacs@m.gmane-mx.org; Tue, 26 Sep 2023 10:54:10 +0200 Original-Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1ql3pH-0005Jn-Kt; Tue, 26 Sep 2023 04:53:51 -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 1ql3pG-0005JJ-5z for bug-gnu-emacs@gnu.org; Tue, 26 Sep 2023 04:53:50 -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 1ql3pF-0007we-NI for bug-gnu-emacs@gnu.org; Tue, 26 Sep 2023 04:53:49 -0400 Original-Received: from Debian-debbugs by debbugs.gnu.org with local (Exim 4.84_2) (envelope-from ) id 1ql3pS-0005bn-Hk for bug-gnu-emacs@gnu.org; Tue, 26 Sep 2023 04:54:02 -0400 X-Loop: help-debbugs@gnu.org Resent-From: Ihor Radchenko Original-Sender: "Debbugs-submit" Resent-CC: bug-gnu-emacs@gnu.org Resent-Date: Tue, 26 Sep 2023 08:54:02 +0000 Resent-Message-ID: Resent-Sender: help-debbugs@gnu.org X-GNU-PR-Message: followup 66117 X-GNU-PR-Package: emacs Original-Received: via spool by 66117-submit@debbugs.gnu.org id=B66117.169571843521547 (code B ref 66117); Tue, 26 Sep 2023 08:54:02 +0000 Original-Received: (at 66117) by debbugs.gnu.org; 26 Sep 2023 08:53:55 +0000 Original-Received: from localhost ([127.0.0.1]:47225 helo=debbugs.gnu.org) by debbugs.gnu.org with esmtp (Exim 4.84_2) (envelope-from ) id 1ql3pL-0005bS-46 for submit@debbugs.gnu.org; Tue, 26 Sep 2023 04:53:55 -0400 Original-Received: from mout01.posteo.de ([185.67.36.65]:52957) by debbugs.gnu.org with esmtp (Exim 4.84_2) (envelope-from ) id 1ql3pH-0005bD-Kl for 66117@debbugs.gnu.org; Tue, 26 Sep 2023 04:53:53 -0400 Original-Received: from submission (posteo.de [185.67.36.169]) by mout01.posteo.de (Postfix) with ESMTPS id 1F769240028 for <66117@debbugs.gnu.org>; Tue, 26 Sep 2023 10:53:32 +0200 (CEST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=posteo.net; s=2017; t=1695718413; bh=8WTURMaQB1hl5XGhBsUWcuEPRLyF2ylGUf1fi4pROw8=; h=From:To:Cc:Subject:Date:Message-ID:MIME-Version:From; b=C8kjQL26Dkf8HLXQT9ZfqKggv3/BdqY4MoXP1xy+MQ/ngaoXnEwDS/CtEwuO8WXZf BXaUsG69g+sqDkBrJxl6fM1vMh8tFYTwjsrkgoY81Mj8TFgAtqM5RZt5XNNVqbirxM yYN5JPGQMPBhH/+b1SSrVjaNG6FUAFdtfvS1Aq7/iYKvqUZEt8YHv1xF5mHD6yl6O9 FgUw6yxC+cvygq4U2w46eHJQ9uDnFynbelr8QMLJqYB7VmtQyEXu8SLyTnrD9ljRD3 Zhhrkw01o0UMiMH2XPQnC7aEmTsnskGTO08g9WvHFiSrB3Zt/3vdsvNOU/HTHCRINi Tahjnkdt1BUFQ== Original-Received: from customer (localhost [127.0.0.1]) by submission (posteo.de) with ESMTPSA id 4RvtnS01LBz6v6M; Tue, 26 Sep 2023 10:53:31 +0200 (CEST) In-Reply-To: <83pm273fc1.fsf@gnu.org> 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:271364 Archived-At: Eli Zaretskii writes: >> I feel that I am still missing where `buffer-file-name' is set when >> opening file via C-x C-f. Debugger showed something weird in my testing. > > With local files, it seems like insert-file-contents sets it. So > maybe we should record the file name in the cache in bset_filename. Thanks for the pointer! AFAIU, the relevant code is if (NILP (handler)) { current_buffer->modtime = mtime; current_buffer->modtime_size = st.st_size; bset_filename (current_buffer, orig_filename); However, it looks like file handlers are responsible for setting the filename. So, > - ~tramp-handle-insert-file-contents~ > - ~tramp-archive-handle-insert-file-contents~ > - ~ange-ftp-insert-file-contents~ > - ~jka-compr-insert-file-contents~ > - ~mm-url-insert-file-contents~ > - ~epa-file-insert-file-contents~ may also need to handle the caching. And also all the third-party handlers. >> Just to make sure that we are on the same page: the cache I am proposing >> should be complete - if a buffer is missing from the cache, we should be >> sure that there is no matching buffer. > > Since we will keep buffer-list (we must), even with this cache > available, we can always leave the current code that scans the buffer > list if the name is not in the cache. This way, we don't need to > worry to have all the buffers in the cache, only those which are > looked for frequently and need the efficiency. I need to elaborate then. The problem Org faces happens when we open a file that is not yet opened in Emacs. So, the FILENAME in question is missing from the buffer list and `find-buffer-visiting' must (1) traverse every buffer in `get-file-buffer'; (2) traverse every buffer again, checking `buffer-file-name' values; (3) traverse every buffer yet again, checking for `buffer-file-number'. We have the worst-case scenario for the current code when the buffer with a given file name is not available and all the checks fail. To address the above scenario, it is not enough to cache _some_ buffer names. Because not-yet-open FILENAME will be missing from the cache, but we will still have to go through the above process, which is slow. What is needed is a _complete_ cache, so that the fact that FILENAME is missing there means that no buffer associated with FILENAME is open in Emacs. >> `find-buffer-visiting' explicitly checks for `buffer-file-truename'. >> So, if the cache does not account for `buffer-file-truename', there will >> be divergence between the existing code and when using the cache. >> >> Same argument for `buffer-file-number' > > As I said, we could have hash-tables for these as well, if that is > needed. But I'd like to see the profiles that indicate we do need > them. I hope that the above clarified why I want to cache everything. >> Most of the time was taken by `find-buffer-visiting'. Replacing >> `find-buffer-visiting' with `get-file-buffer' in certain (not all) >> places reduced the total runtime by 30%. > > So you are saying that 30% of file-visiting buffers are not found by > get-file-buffer? Or is the 30% increase due to file names for which > there's no corresponding buffer? If so, does the benchmark indeed > look for so many buffers that don't exist? The rough code flow for the profile I attached to the initial message is: For each of 500 files used to build agenda: (1) check if file is open in Emacs via `find-buffer-visiting' and open it if not yet open; (2) search the file to find matching headings to be added to agenda. The total CPU time spend building agenda from fresh Emacs decreased by 1/3 (~10 seconds) by replacing calls to `find-buffer-visiting' with `get-file-buffer'. And this replacement did not yet replace every call to `find-buffer-visiting' (in particular, find-file-no-select by itself also calls `find-buffer-visiting'; I replaced no more than half of the calls only). I estimate that over half of the 30 seconds building agenda was spent repeatedly searching over all the buffers. -- Ihor Radchenko // yantar92, Org mode contributor, Learn more about Org mode at . Support Org development at , or support my work at