RE: [platform-core-dev] About the performance of jars and compression :

[Jeff McAffer <Jeff_McAffer@xxxxxxxxxx>]

We did some experiements with class
ordering in the jars.  It is interesting but both costly and quite
sensitive.  The classload order depends on, of course, what you are
doing.  What you are doing depends on the state of the workspace you
open.  This is free to change from run to run.  The lower level
plugins are roughly independent of the workspace but they also only account
for a small fraction of the classes loaded in a typical session.  

Summary, something could be done here
but the net benefit is questionable since it can only be applied to a limited
set of plugins effectively.

Jeff

"Philippe Ombredanne" <pombredanne@xxxxxxxx>
Sent by: platform-core-dev-admin@xxxxxxxxxxx

02/25/2005 02:27 PM

Please respond to
platform-core-dev

To	<platform-core-dev@xxxxxxxxxxx>
cc
Subject	RE: [platform-core-dev] About the performance of jars and compression : some ideas for plugins installed as one jar.

PaScaL scripsit:
>Also  the runtime supports nested jars, we are only interested
in
shipping as "flat jars" where the code is at the root of the
jar. 
>Two reasons to that: first the nested jars have to be exploded which
is
costly and seconds tools such as compilers do not support nested jars.

Sounds quite reasonable to me.
Then in that context, making some experiments with compressed or
uncompressed jars should be easier.
Once again my hunch is that uncompressed will be faster.
If you can tell when I could get a nightly build that has the feature
working, I will give a shot and report here.

The other thing that would be a ultimate refinement is to have class
loading order driving the order in which the file are present in the
jars.
It may be hard to do automatically in practice, but the idea is to get
a
VM started in verbose mode, get the list of classes in the order they
are loaded for a given build, and rebuild the jars so that the class
files are added in that order in their respective jars. That should
oviously be limited to the core statup classes, like the osgi stuff, ad
can provide yet some other startup time improvements.
But hey I guess that would not happen in this life time :-)

--
Cheers
Philippe

philippe ombredanne | nexB - Open by Design (tm)
1 650 799 0949 | pombredanne at nexb.com
http://www.nexb.com 


_______________________________________________
platform-core-dev mailing list
platform-core-dev@xxxxxxxxxxx
http://dev.eclipse.org/mailman/listinfo/platform-core-dev