Review Request 127236: Leverage QDir to know what's in a KIconThemeDir
Aleix Pol Gonzalez
aleixpol at kde.org
Tue Mar 1 12:01:10 UTC 2016
> On March 1, 2016, 10:19 a.m., Kai Uwe Broulik wrote:
> > src/kicontheme.cpp, line 675
> > <https://git.reviewboard.kde.org/r/127236/diff/1/?file=446153#file446153line675>
> >
> > This looks like it causes a lot of transient allocations, creating a QList just to do a contains() on it. Or is this list kept/cached by QFile?
The list is cached by QDir. See there's a `QStringList QDirPrivate::files` defined in qdir_p.h.
- Aleix
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On March 1, 2016, 4:25 a.m., Aleix Pol Gonzalez wrote:
>
> -----------------------------------------------------------
> This is an automatically generated e-mail. To reply, visit:
> https://git.reviewboard.kde.org/r/127236/
> -----------------------------------------------------------
>
> (Updated March 1, 2016, 4:25 a.m.)
>
>
> Review request for KDE Frameworks and Christoph Feck.
>
>
> Repository: kiconthemes
>
>
> Description
> -------
>
> At the moment we're playing Battleship to see if an icon is present in a subdirectory. This means that we are checking on every directory if there's an icon that matches the size with a said name on every request.
>
> This can be seen easily with strace:
> ```
> $ strace kwrite |& grep ENOENT | wc -l
> 6212
> ```
> After the patch:
> ```
> $ strace kwrite |& grep ENOENT | wc -l
> 1993
> ```
> We reduce these accesses to let QDir keep the list of files inside the directory (that was already being generated at some point, it just was being discarded).
>
>
> Diffs
> -----
>
> src/kicontheme.cpp 0996054
>
> Diff: https://git.reviewboard.kde.org/r/127236/diff/
>
>
> Testing
> -------
>
> Builds, tests still pass, applications start noticeably faster.
>
>
> Thanks,
>
> Aleix Pol Gonzalez
>
>
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