bill at BINKO.NET
Tue Oct 18 14:23:01 EDT 2005
> Normally when I run into this sort of problem, I would
> build MapServer in debug mode, and run it in gdb.
> Then hit "cntl-c" a few times during the run and get
> a traceback to see what is going on. This crude sampling
> technique can often identify especially major performance
> If the statistics on msDrawMap() are accurate then the
> bulk of the delay must be somewhere else. Perhaps the
> compression of the PNG (though it does not seem
> especially large) or some sort of preprocessing (getting
> projections during .map processing?)
If shp2img is causing the same issue, you can use qprof to determine the
location of the performance problem. I tried to get it to work on
mapserv, but there is some dynamic loading (of gd) that causes it to fail.
QProf (from HP - http://www.hpl.hp.com/research/linux/qprof/ ) is an
outstanding tool for this. I was considering posting a note to the board
about it, but was hung up on getting mapserv to work w/it.
Basically, you install it (very simple build etc.) and it has a shared
library that is loaded through LD_PRELOAD (which I didn't even know
about). That library samples your app and give a basic profile after each
command is executed. If your apps/libs are built with debugging (-g) it
helps, but it is not necessary for basic performance. There is no need to
build w/ profiling (-p or -pg) and you can run it on apps you didn't build
I'd be happy to help you getit setup and running.
bill.binko at mapshine.com
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