Re: KDE 2.0 impressions

[Drazen Kacar <dave srce hr>]

Padraig O'Briain wrote:

> As Matthias notes, the RSS values give us no idea about the memory usage.
> Does Linux have a command similar to the pmap command on Solaris? This would

Somebody wrote the utility, but people usually use `cat /proc/<pid>/maps'.

KDE applications are implemented as shared objects, ie. there is
/opt/kde/lib/kwrited.so, /opt/kde/lib/kwrite.so, /opt/kde/lib/kicker.so
and so on. This is presumably PIC code, so it's somewhat slower than
non-PIC version.

> give us a view of how much of the process size is shared between processes.
> Although interesting, I do not think that this has much impact on startup
> time for applications. I am assuming that a non-memory constrained world

I think it does...

> although I realize that some people do not inhabit such a world.

...regardless of this. I meant that KDE method has impact, not the amount
of shared code between processes.

> One of the things that we found on Solaris which improved startup performance
> for applications was the use of scope mapfiles. I have not seen these used in
> GNOME so perhaps scope mapfiles are not available on Linux. Could someone

Owen said GTK 2.0 will use symbol scope reduction. I don't know about
other libraries. Probably not planned at this point.

> Solaris also have a feature which allows the code in shared libraries to be
> reordered at link time so that frequently accessed code is clustered together
> and code which is very infrequently used is at the end of the file and is
> never paged in. Windows also has a similar feature for DLLs. Use of such a
> feature can reduce the working set size and paging activity for memory
> constrained systems.  This feature was invaluable when trying to get CDE
> performance to an acceptable level on 32 Mb systems.

If libtool lets you use it, you have my blessing. :-)

> Another feature which is the default on Windows and is available as an option
> on Solaris and I do not know its state on Solaris is to load shared libraries
                                            ^^^^^^^
You meant "other systems," I assume. Available on AIX, IRIX and Mac OS X,
at least.

> only when required rather than automatically on startup. This can make a
> significant difference to the user-perceived startup time if not all shared
> libraries have to be loaded before the user perceives the application to have
> started.

You can't use that with Motif or Xt, but you can use it with GTK if it's
properly linked. Hopefully with otherr GNOME libraries too, but I never
tried.

> It is not clear to me whether there is a performance problem on GNOME but if
> there is, hopefully, we have the tools to fix it.

Methinks direct bindings and group isolation would be very helpful, where
available.

-- 
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(_  \ /  _)
     |        dave srce hr
     |        dave fly srk fer hr