CPU affinity #4
Description
When running multi-threaded (or also with a single thread and with testee on same machine), it seems important for performance (absolulte and consistency) to set the CPU core affinity of each thread.
E.g. I have now implemented that in the Autobahn testee and was able to bring down (essential more than half!) Median and Q90 latencies:
Min: 1.5 ms
SD: 21.0 ms
Avg: 24.8 ms
Median: 16.7 ms
q90 : 42.9 ms
q95 : 75.1 ms
q99 : 105.3 ms
q99.9 : 122.6 ms
q99.99: 129.0 ms
Max: 132.6 ms
When running on e.g. a 8 core machine, having the option to start 'wsperf` like this would be ideal:
wsperf --workers 0,1,2,3 ...
This would then allow to start the testee
testee --workers 4,5,6,7 ...
With Python, there is the psutil package, which relies on the sched_setaffinity system call on Linux.
The feature (setting thread/process CPU affinity) should be available on other platforms as well.