[prev in list] [next in list] [prev in thread] [next in thread] 

List:       kde-core-devel
Subject:    kinit: A new way to start KDE programs!
From:       Waldo Bastian <bastian () suse ! de>
Date:       1999-12-25 22:48:26
[Download RAW message or body]

I've added kdelibs/kinit to CVS for evaluation. Please have a look at 
the readme.

Cheers,
Waldo
--

README
========

kinit is a process launcher somewhat similair to the 
famous init used for booting UNIX.

It launches processes by forking and then loading a
dynamic library which should contain a 'main(...)'
function. 

Executive summary
=================

Using kinit to launch KDE applications makes starting
a typical KDE applications 2.5 times faster (100ms 
instead of 250ms on a P-III 500) It reduces memory 
consumption by approx. 350Kb per application.


How it works
============

kinit is linked against all libraries a standard KDE
application needs. With this technique starting an
application becomes much faster because now only
the application itself needs to be linked whereas 
otherwise both the application as well as all the libaries
it uses need to be linked.

Startup Speed
=============

Starting an application linked against libqt, libkdecore and libkdeui
in the conventional way takes approx. 150ms on a Pentium III - 500Mhz. 
Starting the same application via kinit takes less than 10ms.

(application without KApplication constructor, the KApplication 
constructor requires an extra 100ms in both cases)

Memory Usage
============

An application linked against libqt, libkdecore and libkdeui started
in the conventional way requires about 498Kb memory. 
(average of 10 instances) If the same application is started via
kinit it requires about 142Kb. A difference of 356Kb (application 
without KApplication constructor) 

If we take the KApplication constructor into account, an application
started in the conventional way takes about 679Kb memory while the same
application started via kinit requires about 380Kb. Here the difference
is somewhat less, 299Kb. This seems to be caused by the fact that the
dynamic linker does "lazy linking". We can force the linker to link
everything at startup by specifying "LD_BIND_NOW=true". When kinit is
started with this option on, kinit is back to its full efficiency, an
application with a KApplication constructor now uses 338Kb of memory.
A difference of 341Kb with the normal case.

Adapting programs to use kinit.
===============================

The sourcecode of a program does not require any change to take 
advantage of kinit. Only the makefile requires an adaption, if the 
Makefile.am of a normal program looks like this:

bin_PROGRAMS = kicker   
kicker_LDADD = $(top_builddir)/libkonq/libkonq.la
kicker_LDFLAGS = $(all_libraries) $(KDE_RPATH)

The following lines need to be added to make a library version useable 
by kinit:

lib_LTLIBRARIES = libkicker.la
libkicker_la_LIBADD = $(top_builddir)/libkonq/libkonq.la
libkicker_la_LDFLAGS = $(all_libraries) $(KDE_RPATH) -module            
       
Disadvantages
=============

The process name of applications started via kinit is "kinit". This 
problem can be corrected to a degree by changing the application name 
as shown by 'ps'. However, applications like "killall" will only see 
"kinit" as process name.

[prev in list] [next in list] [prev in thread] [next in thread]