tdelibs/kinit

README

kdeinit is a process launcher somewhat similar 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 kdeinit 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
============

kdeinit 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 kdeinit 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
kdeinit 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 kdeinit 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 kdeinit is
started with this option on, kdeinit 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 kdeinit.
===============================

The sourcecode of a program does not require any change to take advantage
of kdeinit. 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 kdeinit:

lib_LTLIBRARIES = kicker.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 kdeinit is "kdeinit". This problem
can be corrected to a degree by changing the application name as shown
by 'ps'. However, applications like "killall" will only see "kdeinit" as 
process name. To workaround this, use "kdekillall", from kdesdk/scripts,
for applications started via kdeinit.