[bug #53060] [xlib] Significant slowness with some apps, font-related

[Yavor Doganov]

URL:
  <http://savannah.gnu.org/bugs/?53060>

                 Summary: [xlib] Significant slowness with some apps,
font-related
                 Project: GNUstep
            Submitted by: yavor
            Submitted on: Sun 04 Feb 2018 02:06:04 AM EET
                Category: Backend
                Severity: 3 - Normal
              Item Group: Bug
                  Status: None
                 Privacy: Public
             Assigned to: None
             Open/Closed: Open
         Discussion Lock: Any

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Details:

The xlib backend is nearly unusable with some apps.  On my main workstation
(not powerful but with many fonts installed) it takes about a minute for
SimpleAgenda to appear and become responsive.  Then if I click on another tab,
I have to wait ~15 seconds; the UI is blocked until then.

The log shows some of these:

2018-02-04 01:00:14.278 SimpleAgenda[24146:24146] attempt to initialize
character set with invalid bitmap

Putting a break on NSCharacterSet.m:206 reveals:


Breakpoint 1, -[NSBitmapCharSet initWithBitmap:] (self=0x5555574a8340, 
    _cmd=<optimized out>, bitmap=0x5555574140c0) at NSCharacterSet.m:206
206           NSLog(@"attempt to initialize character set with invalid bitmap");
(gdb) p length
$1 = 1114112
(gdb) bt 2
#0  0x00007ffff6848a78 in -[NSBitmapCharSet initWithBitmap:]
(self=0x5555574a8340, _cmd=<optimized out>, bitmap=0x5555574140c0) at
NSCharacterSet.m:206
#1  0x00007ffff68463fc in +[NSCharacterSet
characterSetWithBitmapRepresentation:] (self=<optimized out>, _cmd=<optimized
out>, data=0x5555574140c0)
    at NSCharacterSet.m:800
#2  0x00007fffeb20d919 in -[GSXftFontInfo coveredCharacterSet]
(self=0x555555f376f0, _cmd=<optimized out>) at GSXftFontInfo.m:368


The first patch addresses this but the slowness remains.  With
--GNU-Debug=NSFont, there is intensive output after the loop in
-enumerateFontsAndFamilies.  There are an awful lot of repetitions of the
debug output in -setupAttributes, for the same fonts over and over:

+verabtim+
2018-02-04 01:28:29.778 SimpleAgenda[24287:24287] Loaded font: Samyak Tamil
2018-02-04 01:28:29.805 SimpleAgenda[24287:24287] Loaded font: Noto Sans
Telugu UI
2018-02-04 01:28:29.826 SimpleAgenda[24287:24287] Loaded font: URW Gothic L
2018-02-04 01:28:29.858 SimpleAgenda[24287:24287] Loaded font: TeX Gyre
Cursor
2018-02-04 01:28:29.886 SimpleAgenda[24287:24287] Loaded font: Noto Sans
Malayalam-Bold
2018-02-04 01:28:29.912 SimpleAgenda[24287:24287] Loaded font: STIXGeneral
2018-02-04 01:28:29.948 SimpleAgenda[24287:24287] Loaded font: AnjaliOldLipi
2018-02-04 01:28:29.964 SimpleAgenda[24287:24287] Loaded font: Dingbats
2018-02-04 01:28:29.995 SimpleAgenda[24287:24287] Loaded font: Noto Sans
Oriya-Bold
2018-02-04 01:28:30.023 SimpleAgenda[24287:24287] Loaded font: Chilanka
2018-02-04 01:28:30.049 SimpleAgenda[24287:24287] Loaded font:
LucidaTypewriter
2018-02-04 01:28:30.091 SimpleAgenda[24287:24287] Loaded font: ori1Uni
2018-02-04 01:28:30.120 SimpleAgenda[24287:24287] Loaded font: URW Gothic
L-Demibold
2018-02-04 01:28:30.156 SimpleAgenda[24287:24287] Loaded font: Free
Courier-BoldOblique
2018-02-04 01:28:30.196 SimpleAgenda[24287:24287] Loaded font: FreeSerif-Bold
2018-02-04 01:28:30.227 SimpleAgenda[24287:24287] Loaded font: TeX Gyre Termes
Math
2018-02-04 01:28:30.247 SimpleAgenda[24287:24287] Loaded font: TeX Gyre
Cursor-BoldItalic
2018-02-04 01:28:30.272 SimpleAgenda[24287:24287] Loaded font: Samyak
Gujarati
2018-02-04 01:28:30.297 SimpleAgenda[24287:24287] Loaded font: Noto Sans
Georgian-Bold
2018-02-04 01:28:30.325 SimpleAgenda[24287:24287] Loaded font: Terminal-Bold


The above is just a small snippet from the output.  I have to kill the app
with kill(all) from another terminal.  CPU usage is intensive, and HDD too if
debug output is enabled.  This is reproducible with some apps like
SimpleAgenda, LuserNET, PikoPixel, Preview, Cenon (to an extent), Grr (when
you click on a feed) and especially Charmap.  I cannot reproduce with AClock,
Timemon, Gorm, PRICE, FTP, Ink or SystemPreferences.

The second patch introduces glyph caching in a very similar way as it is done
for the other backends.  I thought initially that this was the culprit but I
was completely wrong.  As I've made it anyway and it is some improvement, I
thought it wouldn't hurt to share it although it doesn't solve the problem.

This bug is reproducible with GUI/Back 0.25.0 as well.  I tried to track down
the issue but there are so many hoops through GSLayoutManager/NSGlyphGenerator
that I got utterly confused at the end, especially when I tried to compare the
behavior with the other backends.  Perhaps a proper programmer would spot and
solve the bug easily.



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File Attachments:


-------------------------------------------------------
Date: Sun 04 Feb 2018 02:06:04 AM EET  Name:
0001-xlib-Protect-against-invalid-characters-in-coveredCh.patch  Size: 1KiB  
By: yavor

<http://savannah.gnu.org/bugs/download.php?file_id=43165>
-------------------------------------------------------
Date: Sun 04 Feb 2018 02:06:04 AM EET  Name:
0002-xlib-Add-support-for-glyph-caching.patch  Size: 3KiB   By: yavor

<http://savannah.gnu.org/bugs/download.php?file_id=43166>

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