import os

import subprocess as sp

def percentile(sequence, percent):

if not sequence:

return None

values = sorted(sequence)

if percent == 0:

return values[0]

pos = int(len(values) * percent) - 1

return values[pos]

def secs(value):

units = ['s ', 'ms', 'us', 'ns']

if value is None:

return ' 0.000ns'

elif value == 0:

return ' 0.000ns'

else:

for unit in units:

if value > 1:

return '%7.3f' % value + unit

else:

value *= 1000

def run(*args):

"""Run command, print output, and return output."""

print('utils$', *args)

result = sp.check_output(args)

print(result)

return result.strip()

def mount_ramdisk(size, path):

"""Mount RAM disk at `path` with `size` in bytes."""

sectors = size / 512

os.makedirs(path)

dev_path = run('hdid', '-nomount', 'ram://%d' % sectors)

run('newfs_hfs', '-v', 'RAMdisk', dev_path)

run('mount', '-o', 'noatime', '-t', 'hfs', dev_path, path)

return dev_path

def unmount_ramdisk(dev_path, path):

"""Unmount RAM disk with `dev_path` and `path`."""

run('umount', path)

run('diskutil', 'eject', dev_path)

run('rm', '-r', path)

def display(name, timings):

cols = ('Action', 'Count', 'Miss', 'Median', 'P90', 'P99', 'Max', 'Total')

template = ' '.join(['%9s'] * len(cols))

print()

print(' '.join(['=' * 9] * len(cols)))

print('Timings for %s' % name)

print('-'.join(['-' * 9] * len(cols)))

print(template % cols)

print(' '.join(['=' * 9] * len(cols)))

len_total = sum_total = 0

for action in ['get', 'set', 'delete']:

values = timings[action]

len_total += len(values)

sum_total += sum(values)

print(

template

% (

action,

len(values),

len(timings.get(action + '-miss', [])),

secs(percentile(values, 0.5)),

secs(percentile(values, 0.9)),

secs(percentile(values, 0.99)),

secs(percentile(values, 1.0)),

secs(sum(values)),

)

)

totals = ('Total', len_total, '', '', '', '', '', secs(sum_total))

print(template % totals)

print(' '.join(['=' * 9] * len(cols)))

print()