Re: Load times of Linux Applications

Hello,

newbei wrote:

I am using qtopia with Qt-embedded as the base on linux platform
I am not very happy with the application load times.

Then maybe this is due to dynamic linking. This used to be a hot subject
a few years ago, when KDE based on Qt had similar problems. Due to
tables of virtual functions, being extensively used by Qt and typical
development methods involving lots of classes with virtual methods,
lots of symbols have to be looked up, initially.

The KDE community has tried several things to improve the situation,
some of which you already have heard about:

* minimizing dynamically resolved symbols, avoiding development methods
involving lots of methods and classes (e.g. uic can easily cause extra
classes to separate between generated and manually edited code)
* object prelinking (use google)
* Forking applications and dynamically loading components instead of
running new applications, to save symbols already loaded.

Later releases of gcc have symbol visibility features, which allow to
minimize the symbols of shared libraries exposed to users thus
minimizing the number of symbols involved in dynamic resolution. I
think binutils have been supporting selective visibility for a long
time, but in a manner that is not easy to use for C++ code without
compiler support.

In the end I think the efforts of the KDE community have been quite
successful on this. And there used to be lots of pages in the internet
documenting how it is done, and what the results are.

Can the community give me some suggestions how to improve the
performance

I think it is the dynamic linking, which is your problem, but nobody can
be really sure until more is known about your app and the overall
system. If it is the only Qt-app running, then linking statically might
help a lot, given you have static libs.

Bernd Strieder

.