[Benchmarking] where is the bottleneck?

[Eric Lemoine]

Hi

I just wanted to mention something that I think was lacking in last
year's performance shoutout.

The performance results didn't include numbers reporting on the usage
of system resources. When the throughput (req/s) reaches a limit it
means there's a bottleneck somewhere, it can be the CPU, the network
or the disk. Reporting on the CPU, network and disk usage would I
think be very valuable.

For example, if I recall correctly, MS et GS exhibited the same exact
throughput numbers. This was quite surprising. I tend to think that
this was because the bottleneck wasn't in the execution of the map
server application, but in the I/O, probably in the network
communication between the map server and PostGIS. If we had CPU and
network usage numbers in addition to the throughput numbers this could
have brought some light on the results.

I know that gathering performance numbers is time-expensive, and that
measuring system resource usage would yield even more work, yet I
thought I should mention that ;-)

I'm looking foward to the Barcelona shoutout.

Cheers,

-- 
Eric Lemoine

Camptocamp France SAS
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Tel : 00 33 4 79 44 44 96
Mail : eric.lemoine at camptocamp.com
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