perf - check the performance arguments of a program
If you want to investigate the performance arguments, like clock cycles, cpu utilize rate, etc., of a program under Linux, perf is a great tool here to help you.
Installation
$ sudo apt update && sudo apt install linux-tools-$(uname -r) linux-tools-generic
(ref: http://www.tecmint.com/perf-performance-monitoring-and-analysis-tool-for-linux/)
Simple Usage
$ ll test
-rwxr-xr-x 1 root root 8608 Mar 14 10:55 test*
$ perf stat ./test
haha <-------- this is the output of test*
Performance counter stats for './test':
0.433868 task-clock (msec) # 0.564 CPUs utilized
0 context-switches # 0.000 K/sec
0 cpu-migrations # 0.000 K/sec
49 page-faults # 0.113 M/sec
<not supported> cycles
<not supported> stalled-cycles-frontend
<not supported> stalled-cycles-backend
<not supported> instructions
<not supported> branches
<not supported> branch-misses
0.000769191 seconds time elapsed
Some items say , like cycles/instructions. It's because the linux kernel doesn't support them.
$ perf list
You can view all the available arguments here.
$ perf stat -e cycles-ct -e cycles-t ./test
Performance counter stats for './test':
745,964 cycles-ct
747,306 cycles-t
0.000888103 seconds time elapsed
This might give you some hints about the cpu cycles
$ perf stat -e task-clock ./test
Performance counter stats for './test':
0.423036 task-clock (msec) # 0.511 CPUs utilized
0.000828073 seconds time elapsed
task-clock means the total cpu(s) execution time (msec) for just this task. 0.511 represents the utilize rate of this task over the whole cpu(s).
This number is calculated by task-clock/totaltime(shown in the last line). In this case, 0.511 = 0.423036(msec)/0.000828073(sec)
