[mapserver-dev] MapScript multithreading performance

[adrian kruk]

>
> It would be useful however to extract proper execution times related
> to the different operations (like map initialization, drawing etc.).

Map init takes 30-700ms, mostly 100-200ms
SetExtent, zoomPoint - very fast <<15ms (so fast that cannot catch)


> What happens is only one thread is executing and do subsequents drawings?

One processor is in 100% usage


> Is the CPU utilization larger when only a few of the threads (5-6)
> executed simultaneously?

Processors was in 100% usage (95% my application + 5% other processes)

These resuslts I get after creating ramdisk and coping all shapefile to new
drive.
These are processors usage results for different numbers of threads

Threads number : usage

1:25
2:45-50
4:70-95
8:70-95
16:85-95
32:85-95
64:85-95
128:25-95
256:25-80

The last tests was interesting. After creating mapobjects ( usage was 100%),
usage decrease to 25%, but
after some time it started to very slow increasing.
In my test application at start all mapObjects has big scale value, but
while running scale value is decreasing.

So I think that it depends on scale value. I have a look at the log file. If
scale value was big (>10^6) then usage was low.
But after minutes when scale values was less (<20000) for most of threads,
usage incresed to 80%.

So I think that usage depends on number of features and/or labels which are
rendered. Number of features and/or labels affects drawing time. Long
drawing times for most of threads affects low usage. Why?

I will check what happened if at the same time scales values will be more
different. It will be more realistic.

Best regards,
Adrian
-------------- next part --------------
An HTML attachment was scrubbed...
URL: http://lists.osgeo.org/pipermail/mapserver-dev/attachments/20080213/419811bb/attachment.html