Where does Linux Ubuntu CPU load spikes come from?

Question

linux

Hello!
Please help me to figure out how to load linux processor.
I have a Xen Cloud Platform virtual machine running Linux Ubuntu 10.04 LTS x86. The virtual machine has a web application that sends HTTP requests to an arbitrary site. The number of requests gradually increases (the requests are the same, only their number increases), i.e. in theory, the processor load should also gradually increase.
And that's what happens in the beginning. When you run a web application, the processor load is 2% and it gradually increases (this happens for 10 minutes), but then there is a sharp jump to 80% and the indicator of 80-90% lasts 40 seconds. After that, the load again drops to 2% and begins to gradually grow.
The load gradually increases means an increase of 0.1.
I measure the download every 2 seconds, with the command
ps aux | awk '{s += $3} END {print s }'
Where does this jump come from?

Answer 1

Are you sure that this application creates load spikes?
Perhaps you have some task run by cron or something else.
Try putting atop. Reduce the statistics collection interval for it to 10 seconds. and then look in the log what really happens on the server.

Answer 2

Linux has a lot of services that run intermittently, so it's nothing special I guess. Is cron disabled?

Answer 3

look at the load in top
and immediately everything will become clear