We have created an ECS/Fargate container with 2 VCPU and 4 GB RAM, running a NodeJS server in it. When we do the load testing using JMeter the VCPU reaches a maximum of 60% and flats out with the memory utilization close to 10%. Even when we increase the load using the JMeter it's all the same.
What could be the reason that the CPU reaches a maximum of 60% and flats out?
What could be the reason that the CPU reaches a maximum of 60% and flats out?
The CPU doesn't reach 60% but reaches 100%.
When your application is single threaded and the limiting factor is the CPU , then CPU 1 will be running at 100%.
Divide 100% by the number of CPU 's in total , by two and you get an overall system load of ±50%.
Now normally the second CPU won't be completely idle, there will be some other processes running in addition to the application that you're testing, that maybe adds, let's say, 20% load on CPU number two.
Then you get a system load of:
100 + 20
-------- = 60%
2
(Note that this only a completely random guess and your problem may be something much more interesting than an artefact of how load is calculated.)
