[Hawkular-dev] Running perf tests with 2 h-metrics instances on the same host - results

[Filip Brychta]

Hello,
I finished quick testing of two h-metrics instances running on the same host both using the same external cassandra node.
Motivation for this was to find a bottleneck.

>From previous testing we know following:
- with additional h-metric instance the throughput was increased almost linearly
- question was why it's not possible to get higher throughput from single h-metrics instance while we know that cassandra node is not the bottleneck

Test:
1 - run perf tests against 1 h-metrics with 4GB memory using one external cassandra node
2 - run perf tests against 2 h-metrics with 2GB memory each (on the same VM as previous test) using one external cassandra node (again the same VM as previous test)
3 - compare results

Results:
- for small msgs (1 metrics per request) there was almost no difference -> CPU was fully utilized -> for small msgs the CPU is bottleneck
- for bigger msgs (100 metrics per request) total throughput was almost 2 times better -> it's possible to get 2 times better throughput from the same VM -> neither cpu, nor memory, nor network is the bottleneck -> h-metrics is doing some kind of throttling
- I tried 500 metrics per request as well but I was getting timout exceptions. Maybe it was too much for this VM.


Filip