Source code for spinn_utilities.timer

# Copyright (c) 2017-2018 The University of Manchester
#
# This program is free software: you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program.  If not, see <http://www.gnu.org/licenses/>.
import sys
import time
from datetime import timedelta

if sys.version_info >= (3, 7):
    # acquire the most accurate measurement available (perf_counter_ns)
    _now = time.perf_counter_ns
    # conversion factor
    _NANO_TO_MICRO = 1000.0

    def _convert_to_timedelta(time_diff):
        """ Have to convert to a timedelta for rest of code to read.

        As perf_counter_ns is nano seconds, and time delta lowest is micro,
        need to convert.
        """
        return timedelta(microseconds=time_diff / _NANO_TO_MICRO)

else:
    # acquire the most accurate measurement available (perf_counter)
    _now = time.perf_counter

    def _convert_to_timedelta(time_diff):
        """ Have to convert to a timedelta for rest of code to read.

        As perf_counter is fractional seconds, put into correct time delta.
        """
        return timedelta(seconds=time_diff)


[docs]class Timer(object): """ A timer used for performance measurements. Recommended usage:: with Timer() as timer: ... do stuff that takes time ... elapsed_time = timer.measured_interval or alternatively:: timer = Timer() timer.start_timing() ... do stuff that takes time ... elapsed_time = timer.take_sample() Mixing these two styles is *not recommended*. """ __slots__ = [ # The start time when the timer was set off "_start_time", # The time in the measured section "_measured_section_interval" ] def __init__(self): self._start_time = None self._measured_section_interval = None
[docs] def start_timing(self): """ Start the timing. Use :py:meth:`take_sample` to get the end. """ self._start_time = _now()
[docs] def take_sample(self): """ Describes how long has elapsed since the instance that the\ :py:meth:`start_timing` method was last called. :rtype: datetime.timedelta """ time_now = _now() diff = time_now - self._start_time return _convert_to_timedelta(diff)
def __enter__(self): self.start_timing() return self def __exit__(self, *_args): self._measured_section_interval = self.take_sample() return False @property def measured_interval(self): """ Get how long elapsed during the measured section. :rtype: datetime.timedelta """ return self._measured_section_interval