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""" Some support code
"""
import re, sys, os, subprocess
def detect_number_of_processors(filename_or_file='/proc/cpuinfo'):
if os.environ.get('MAKEFLAGS'):
return 1 # don't override MAKEFLAGS. This will call 'make' without any '-j' option
if sys.platform == 'darwin':
return sysctl_get_cpu_count('/usr/sbin/sysctl')
elif sys.platform.startswith('freebsd'):
return sysctl_get_cpu_count('/sbin/sysctl')
elif not sys.platform.startswith('linux'):
return 1 # implement me
try:
if isinstance(filename_or_file, str):
f = open(filename_or_file, "r")
else:
f = filename_or_file
count = max([int(re.split('processor.*(\d+)', line)[1])
for line in f.readlines()
if line.startswith('processor')]) + 1
if count >= 4:
return max(count // 2, 3)
else:
return count
except:
return 1 # we really don't want to explode here, at worst we have 1
def sysctl_get_cpu_count(cmd, name='hw.ncpu'):
try:
proc = subprocess.Popen([cmd, '-n', name], stdout=subprocess.PIPE)
count = proc.communicate()[0]
return int(count)
except (OSError, ValueError):
return 1
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