From mboxrd@z Thu Jan 1 00:00:00 1970 Path: news.gmane.org!not-for-mail From: Stefan Monnier Newsgroups: gmane.emacs.bugs Subject: bug#16526: 24.3.50; scroll-conservatively & c-mode regression Date: Fri, 04 Jul 2014 15:11:24 -0400 Message-ID: References: <53AFE536.7010407@gmx.at> <20140629124829.GC2948@acm.acm> <53B02042.1050107@gmx.at> <20140629144151.GD2948@acm.acm> <53B03876.9070307@gmx.at> <20140629174953.GE2948@acm.acm> <53B117D6.1050306@gmx.at> <20140702200522.GB3823@acm.acm> <20140704182709.GA3535@acm.acm> NNTP-Posting-Host: plane.gmane.org Mime-Version: 1.0 Content-Type: text/plain X-Trace: ger.gmane.org 1404501162 3275 80.91.229.3 (4 Jul 2014 19:12:42 GMT) X-Complaints-To: usenet@ger.gmane.org NNTP-Posting-Date: Fri, 4 Jul 2014 19:12:42 +0000 (UTC) Cc: 16526@debbugs.gnu.org To: Alan Mackenzie Original-X-From: bug-gnu-emacs-bounces+geb-bug-gnu-emacs=m.gmane.org@gnu.org Fri Jul 04 21:12:35 2014 Return-path: Envelope-to: geb-bug-gnu-emacs@m.gmane.org Original-Received: from lists.gnu.org ([208.118.235.17]) by plane.gmane.org with esmtp (Exim 4.69) (envelope-from ) id 1X38uO-0005d8-TN for geb-bug-gnu-emacs@m.gmane.org; Fri, 04 Jul 2014 21:12:33 +0200 Original-Received: from localhost ([::1]:37789 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1X38uO-0003Ry-Dy for geb-bug-gnu-emacs@m.gmane.org; Fri, 04 Jul 2014 15:12:32 -0400 Original-Received: from eggs.gnu.org ([2001:4830:134:3::10]:52227) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1X38uC-0003RC-9p for bug-gnu-emacs@gnu.org; Fri, 04 Jul 2014 15:12:28 -0400 Original-Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1X38u3-0006mR-UY for bug-gnu-emacs@gnu.org; Fri, 04 Jul 2014 15:12:20 -0400 Original-Received: from debbugs.gnu.org ([140.186.70.43]:51970) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1X38tu-0006hI-TK; Fri, 04 Jul 2014 15:12:02 -0400 Original-Received: from Debian-debbugs by debbugs.gnu.org with local (Exim 4.80) (envelope-from ) id 1X38tu-0001HD-Cb; Fri, 04 Jul 2014 15:12:02 -0400 X-Loop: help-debbugs@gnu.org Resent-From: Stefan Monnier Original-Sender: "Debbugs-submit" Resent-CC: bug-gnu-emacs@gnu.org, bug-cc-mode@gnu.org Resent-Date: Fri, 04 Jul 2014 19:12:02 +0000 Resent-Message-ID: Resent-Sender: help-debbugs@gnu.org X-GNU-PR-Message: followup 16526 X-GNU-PR-Package: emacs,cc-mode X-GNU-PR-Keywords: Original-Received: via spool by 16526-submit@debbugs.gnu.org id=B16526.14045011114889 (code B ref 16526); Fri, 04 Jul 2014 19:12:02 +0000 Original-Received: (at 16526) by debbugs.gnu.org; 4 Jul 2014 19:11:51 +0000 Original-Received: from localhost ([127.0.0.1]:43120 helo=debbugs.gnu.org) by debbugs.gnu.org with esmtp (Exim 4.80) (envelope-from ) id 1X38ti-0001Gm-Rq for submit@debbugs.gnu.org; Fri, 04 Jul 2014 15:11:51 -0400 Original-Received: from mercure.iro.umontreal.ca ([132.204.24.67]:44325) by debbugs.gnu.org with esmtp (Exim 4.80) (envelope-from ) id 1X38tg-0001Gc-6a for 16526@debbugs.gnu.org; Fri, 04 Jul 2014 15:11:49 -0400 Original-Received: from hidalgo.iro.umontreal.ca (hidalgo.iro.umontreal.ca [132.204.27.50]) by mercure.iro.umontreal.ca (Postfix) with ESMTP id D3C0E84EBA; Fri, 4 Jul 2014 15:11:47 -0400 (EDT) Original-Received: from lechon.iro.umontreal.ca (lechon.iro.umontreal.ca [132.204.27.242]) by hidalgo.iro.umontreal.ca (Postfix) with ESMTP id D78F91E5B8A; Fri, 4 Jul 2014 15:11:24 -0400 (EDT) Original-Received: by lechon.iro.umontreal.ca (Postfix, from userid 20848) id A8FEDB4167; Fri, 4 Jul 2014 15:11:24 -0400 (EDT) In-Reply-To: <20140704182709.GA3535@acm.acm> (Alan Mackenzie's message of "Fri, 4 Jul 2014 18:27:09 +0000") User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/24.4.50 (gnu/linux) X-DIRO-MailScanner-Information: Please contact the ISP for more information X-DIRO-MailScanner: Found to be clean X-DIRO-MailScanner-SpamCheck: n'est pas un polluriel, SpamAssassin (score=-2.82, requis 5, autolearn=not spam, ALL_TRUSTED -2.82, MC_TSTLAST 0.00) X-DIRO-MailScanner-From: monnier@iro.umontreal.ca X-BeenThere: debbugs-submit@debbugs.gnu.org X-Mailman-Version: 2.1.15 Precedence: list X-detected-operating-system: by eggs.gnu.org: GNU/Linux 3.x X-Received-From: 140.186.70.43 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-bounces+geb-bug-gnu-emacs=m.gmane.org@gnu.org Xref: news.gmane.org gmane.emacs.bugs:91189 Archived-At: >> Can you try the patch below (for the emacs-24 branch), which tries to >> make the existing cache in find_defun_start do something useful in the >> case where find_defun_start returns BEGV? > [ patch snipped ] > I'm not sure what I'm meant to see, An improvement in performance. > but it has made no perceptible difference to the "slow" invocation of > scan-lists. In particular, that invocation took 0.7196781635284424 > seconds with the patch, which is "exactly" (near enough) what it > took before. Oh well. What he patch does (or should do, at least) is that after a "full scan from BOB", it remembers the last top-level open paren seen, so that if the next back_comment's lossage happens in that same area, we only rescan from that open paren rather than from BOB. If it makes no measurable difference for your case, I see two explanations: - a bug in the patch makes it do something else than what I wanted. - lossage rarely happens more than "once per top-level paren", so the cache is almost never re-used anyway. But since in your case it's a single scan-lists call that's slow and that call only skips one single "sexp", the second explanation seems wrong: you do see several occurrences of lossage (which together cause the slowdown) and yet this is all within the same top-level paren. Stefan