CPU Utilization while using locust

1
votes

We are planning to use locust for performance testing. I have started locust in distributed mode on Kubernetes, with 800 Users for a duration of 5 minutes. Hatch rate is 100 as well. After a couple of minutes, I can see the below warning on the worker log.

[2020-07-15 07:03:15,990] pipeline1-locust-worker-1-gp824/WARNING/root: Loadgen CPU usage above 90%! This may constrain your throughput and may even give inconsistent response time measurements!

I am unable to figure what is 90% here since I have not specified any resource limits. Is it the 90% of node capacity? Which is unlikely since we use beefy nodes, 16Vcpus, and 128Gb memory. Can anyone give any insight?

1
locust

1 Answers

1
votes

It is 90% of one core (which is all a single locust process can utilize because of the python GIL) (measured using https://psutil.readthedocs.io/en/latest/#psutil.Process.cpu_percent)

If you have 16vcpu you need 16 processes to utilize the whole node.

I guess we should clarify the message.