If Python 3 is an option, you have two choices:

• time.perf_counter which always use the most accurate clock on your platform. It does include time spent outside of the process.
• time.process_time which returns the CPU time. It does NOT include time spent outside of the process.

The difference between the two can be shown with:

from time import (
    process_time,
    perf_counter,
    sleep,
)

print(process_time())
sleep(1)
print(process_time())

print(perf_counter())
sleep(1)
print(perf_counter())

Which outputs:

0.03125
0.03125
2.560001310720671e-07
1.0005455362793145