From: Dmitry Gutov <dgutov@yandex.ru>
To: Eli Zaretskii <eliz@gnu.org>
Cc: npostavs@users.sourceforge.net, 28695@debbugs.gnu.org, bryan@bryan.sh
Subject: bug#28695: 26.0.60; Rendering lag spikes caused by double-buffering on Linux
Date: Mon, 16 Oct 2017 01:55:54 +0300 [thread overview]
Message-ID: <a7913e45-8112-9d29-ee9e-45e90b174743@yandex.ru> (raw)
In-Reply-To: <83shesquyu.fsf@gnu.org>
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.
next prev parent reply other threads:[~2017-10-15 22:55 UTC|newest]
Thread overview: 23+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-10-04 3:10 bug#28695: 26.0.60; Rendering lag spikes caused by double-buffering on Linux Bryan Gilbert
2017-10-04 7:53 ` Eli Zaretskii
2017-10-04 9:04 ` martin rudalics
2017-10-04 9:32 ` Eli Zaretskii
2017-10-04 11:21 ` Bryan Gilbert
2017-10-04 11:36 ` Eli Zaretskii
2017-10-04 12:02 ` Bryan Gilbert
2017-10-04 12:31 ` Eli Zaretskii
2017-10-05 13:36 ` Dmitry Gutov
2017-10-05 14:01 ` Eli Zaretskii
2017-10-05 14:02 ` Noam Postavsky
2017-10-07 7:53 ` Dmitry Gutov
2017-10-07 8:14 ` Eli Zaretskii
2017-10-09 13:53 ` Dmitry Gutov
2017-10-09 14:03 ` Eli Zaretskii
2017-10-15 22:55 ` Dmitry Gutov [this message]
2017-10-16 2:30 ` Eli Zaretskii
2017-10-26 23:19 ` Dmitry Gutov
2017-10-28 9:33 ` Eli Zaretskii
2017-10-28 21:47 ` bug#28695: 26.0.60; Rendering lag spikes caused by double-buffering on GNU/Linux Richard Stallman
2017-10-05 14:26 ` bug#28695: 26.0.60; Rendering lag spikes caused by double-buffering on Linux Bryan Gilbert
2022-04-23 13:46 ` Lars Ingebrigtsen
2022-05-22 11:28 ` Lars Ingebrigtsen
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