I am using ab as benchmark tool for performance analysis on apache server

Question

I am using AB as benchmark tool for performance analysis on apache server. Is there any way, we can restrict the AB request to specific CPU cores by setting their mask? I tried with sched_setaffinity() but it restricts the AB request to a single particular core instead I want to restrict it to specific cores . For examples : If I set mask- 0xf0 CPU cores 2,4,6 get disabled.

Answer 1

I don't think there is a specific way to do this.

You could do one of the following:

1. Restrict the concurrency level to control CPU usage.
2. Use the operating system to assign the ab process to a particular Core.

Answer 2

Can use taskset like

taskset x ab -n 100 -c 12 http://localhost/index.html

to set the cpu affiinity to a certain core.

x is the affinity mask and

x = 1 =>core 0
x = 2 =>core 1
x = 4 =>core 2
x = 8 =>core 3

Similarly odd numbered values for x will enable two or more cores