python-peps/pep-0418/clock_precision.py

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import time
def compute_precision(func):
previous = func()
precision = None
points = 0
min_points = 100
while points < min_points:
value = func()
if value == previous:
continue
dt = value - previous
previous = value
if precision is not None:
precision = min(precision, dt)
else:
precision = dt
if precision < 10e-6:
min_points = 5000
elif precision < 1e-3:
min_points = 1000
points += 1
return dt
def format_duration(dt):
if dt >= 1e-3:
return "%.1f ms" % (dt * 1e3)
if dt >= 1e-6:
return "%.1f µs" % (dt * 1e6)
else:
return "%.1f ns" % (dt * 1e9)
def test_clock(name, func):
precision = compute_precision(func)
print("%s:" % name)
print("- precision in Python: %s" % format_duration(precision))
for name in ('clock', 'perf_counter', 'process_time', 'monotonic', 'time'):
func = getattr(time, name)
test_clock("%s()" % name, func)
info = time.get_clock_info(name)
if 'precision' in info:
print("- announced precision: %s" % format_duration(info['precision']))
print("- function: %s" % info['function'])
print("- resolution: %s" % format_duration(info['resolution']))
clock_ids = [name for name in dir(time) if name.startswith("CLOCK_")]
for clock_id_text in clock_ids:
clock_id = getattr(time, clock_id_text)
name = 'clock_gettime(%s)' % clock_id_text
def gettime():
return time.clock_gettime(clock_id)
test_clock(name, gettime)