From mboxrd@z Thu Jan 1 00:00:00 1970 Path: news.gmane.org!.POSTED!not-for-mail From: Dmitry Gutov Newsgroups: gmane.emacs.bugs Subject: bug#28695: 26.0.60; Rendering lag spikes caused by double-buffering on Linux Date: Mon, 16 Oct 2017 01:55:54 +0300 Message-ID: References: <8760bvd2w7.fsf@bryan.sh> <59D4A431.7010801@gmx.at> <831smjz2b2.fsf@gnu.org> <874lrfcg4s.fsf@bryan.sh> <1931afeb-51cb-89c9-72ff-c8a062fecba7@yandex.ru> <0e4817c9-f3f3-875d-2c81-97821c839a29@yandex.ru> <83376vv0gm.fsf@gnu.org> <859fe715-e455-128d-5fca-6f2df4ad0eaf@yandex.ru> <83shesquyu.fsf@gnu.org> NNTP-Posting-Host: blaine.gmane.org Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 7bit X-Trace: blaine.gmane.org 1508108239 1264 195.159.176.226 (15 Oct 2017 22:57:19 GMT) X-Complaints-To: usenet@blaine.gmane.org NNTP-Posting-Date: Sun, 15 Oct 2017 22:57:19 +0000 (UTC) User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:56.0) Gecko/20100101 Thunderbird/56.0 Cc: npostavs@users.sourceforge.net, 28695@debbugs.gnu.org, bryan@bryan.sh To: Eli Zaretskii Original-X-From: bug-gnu-emacs-bounces+geb-bug-gnu-emacs=m.gmane.org@gnu.org Mon Oct 16 00:57:14 2017 Return-path: Envelope-to: geb-bug-gnu-emacs@m.gmane.org Original-Received: from lists.gnu.org ([208.118.235.17]) by blaine.gmane.org with esmtp (Exim 4.84_2) (envelope-from ) id 1e3rqE-0007NP-LX for geb-bug-gnu-emacs@m.gmane.org; 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Sun, 15 Oct 2017 15:55:57 -0700 (PDT) Original-Received: from [192.168.1.3] ([185.105.174.193]) by smtp.googlemail.com with ESMTPSA id n14sm6815598wrg.38.2017.10.15.15.55.55 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Sun, 15 Oct 2017 15:55:56 -0700 (PDT) In-Reply-To: <83shesquyu.fsf@gnu.org> Content-Language: en-US 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: 208.118.235.43 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:138482 Archived-At: On 10/9/17 5:03 PM, Eli Zaretskii wrote: > I think this page (which you probably already know about) is a good > starting point: > > http://www.brendangregg.com/perf.html I still haven't found the appropriate recipe there, but somebody else on the internet suggested this, effectively: sudo perf record -g src/emacs # produces perf.data sudo perf report -g -i perf.data > Well, you saw a difference between a 4K display and a 2K display, > didn't you? All we need is to compare 2 situations and see where's > the extra time spent. A certain difference, but not a stark one. Like, I couldn't produce a full-on stuttering even with 4K (sometimes the gears continue spinning fine; probably has something to do with thread or process scheduling). With a small-window Emacs, the gears are spinning mostly fine. Here are the window configurations: 1. Emacs fullscreen, 4K. 2. Emacs in a small window, much less than 2K. Unfortunately, and if I'm reading the report right, XdbeSwapBuffers takes only 0,03% of CPU time in the first case and 0,02% in the second case. So, less than 1 percent in both cases. Here's how it looks. I search for the function name in the report program, and it shows something like this: Children Self Comma Shared Object Symbol 0,03% 0,03% emacs libXext.so.6.4.0 [.] XdbeSwapBuffers 0,00% 0,00% emacs emacs [.] XdbeSwapBuffers@plt I'm not quite sure if perf.data contains sensitive information, but I'd be happy to send you the files produced by both scenarios for further analysis. Questions welcome, too.