Count number of physical cpu cores to determine the number of parallel processes when using multiprocessing module in Python

physical_cpu_core_count.py

import re

# Assume a system where /proc/cpuinfo exists. We will just parse this file with re module.
cpu_info = open("/proc/cpuinfo").read()

# Pattern of the line in "/proc/cpuinfo" which has the needed count:
#    cpu cores  : 12
patc = re.compile(r"cpu cores\s:\s(\d+)")

# Search and extract.
mo = patc.search(cpu_info)
core_count = int(mo.group(1))