[Development] Cut 7+ms of Qt5 startup time on Linux

[Jiergir Ogoerg]

The .compose-cache file stays empty even after a few reboots.
Using Fedora 20 KDE version, 64 bit.

I noticed the post is 5+ years old, has it been tested on
(modern) Fedora and does it still work with modern versions of Kubuntu?

Particularly, what should I do to make it work on Fedora (20)?



On Thu, Oct 31, 2013 at 12:09 PM, Robert Knight <robertknight at gmail.com>wrote:

> There is already a caching mechanism in place for the Compose file,
> can we make use of that? -
> http://kdemonkey.blogspot.co.uk/2008/04/magic-trick.html
>
> On 31 October 2013 07:38, Knoll Lars <Lars.Knoll at digia.com> wrote:
> > Before going to a binary format, I’d first like to check whether we can
> > further speed up the parsing. I’ve done some work in that area in spring,
> > but I know there was still quite some room to improve it.
> >
> > Cheers,
> > Lars
> >
> > From: Jiergir Ogoerg <f35f22fan at gmail.com>
> > Date: torsdag 31. oktober 2013 04:10
> > To: "<development at qt-project.org>" <development at qt-project.org>
> > Subject: [Development] Cut 7+ms of Qt5 startup time on Linux
> >
> > Hi,
> >
> > Since each qt (gui) app on Linux parses the text file
> > /usr/share/X11/locale/en_US.UTF-8/Compose
> > line by line which on my computer is 549Kib (almost 6000 lines)
> > it takes on my 64bit OS with Intel Core i5 about 7ms to parse,
> > so the idea is to cache the locale file in binary format in the
> > home/.kde directory (the binary file is also smaller than the other one),
> > this new way takes less than 1ms to load since
> > there's pretty much nothing to parse.
> > That's the core idea.
> > The user's locale changes (very) rarely if at all, so pretty
> > much all the time he'll load the cached (quick) version,
> > but when the locale does change or gets updated -
> > the cache is updated accordingly.
> >
> > If this approach isn't good stop reading here and please let me
> > know.
> >
> > I attached the 2 files in zip format.
> >
> > The source code is rather dirty cause it doesn't strictly adhere
> > to the Qt coding style - my goal was a working solution.
> >
> > Since I don't represent any company and the changes are simple
> > would somebody please take the changes and shape them into a
> > mergeable commit or must I take all the steps to become an
> > official contributor and polish the code to a mergeable state myself?
> >
> > Only 2 files affected:
> >
> /qtbase/src/plugins/platforminputcontexts/compose/generator/qtablegenerator.cpp
> > and
> >
> /qtbase/src/plugins/platforminputcontexts/compose/generator/qtablegenerator.h
> >
> >
> > _______________________________________________
> > Development mailing list
> > Development at qt-project.org
> > http://lists.qt-project.org/mailman/listinfo/development
> >
>
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