iSharkFly-Open
/
python-peps
mirror of https://github.com/python/peps.git
1
0
Fork 0
Code Issues Packages Projects Releases Wiki Activity

PEP 418: time.process_time() uses os.times() if available

This commit is contained in:
Victor Stinner 2012-04-13 14:04:37 +02:00
parent 61b5e2476c
commit afc9ba4a20
1 changed files with 30 additions and 22 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

52
pep-0418.txt
View File

@ -213,6 +213,14 @@ Pseudo-code [#pseudo]_::
process_times = win32process.GetProcessTimes(handle) process_times = win32process.GetProcessTimes(handle)
return (process_times['UserTime'] + process_times['KernelTime']) * 1e-7 return (process_times['UserTime'] + process_times['KernelTime']) * 1e-7
else: else:
import os
try:
import resource
except ImportError:
has_resource = False
else:
has_resource = True
def process_time(): def process_time():
if process_time.use_process_cputime: if process_time.use_process_cputime:
try: try:
@ -220,27 +228,24 @@ Pseudo-code [#pseudo]_::
except OSError: except OSError:
process_time.use_process_cputime = False process_time.use_process_cputime = False
if process_time.use_getrusage: if process_time.use_getrusage:
if process_time.getrusage is None: try:
try: usage = resource.getrusage(resource.RUSAGE_SELF)
import resource return usage[0] + usage[1]
except ImportError: except OSError:
process_time.use_getrusage = False process_time.use_getrusage = False
else: if process_time.use_times:
def getrusage(): try:
usage = resource.getrusage(resource.RUSAGE_SELF) times = os.times()
return usage[0] + usage[1] return times[0] + times[1]
process_time.getrusage = getrusage except OSError:
if process_time.use_getrusage: process_time.use_getrusage = False
try:
return process_time.getrusage()
except OSError:
process_time.use_getrusage = False
return _time.clock() return _time.clock()
process_time.use_process_cputime = ( process_time.use_process_cputime = (
hasattr(time, 'clock_gettime') hasattr(time, 'clock_gettime')
and hasattr(time, 'CLOCK_PROCESS_CPUTIME_ID')) and hasattr(time, 'CLOCK_PROCESS_CPUTIME_ID'))
process_time.use_getrusage = True process_time.use_getrusage = has_resource
process_time.getrusage = None # On OS/2, only the 5th field of os.times() is set, others are zeros
process_time.use_times = (hasattr(os, 'times') and os.name != 'os2')
Existing functions Existing functions
@ -1016,6 +1021,7 @@ Name Resolution Include sleep
GetProcessTimes() 100 ns No GetProcessTimes() 100 ns No
CLOCK_PROCESS_CPUTIME_ID 1 ns No CLOCK_PROCESS_CPUTIME_ID 1 ns No
getrusage() 1 µs No getrusage() 1 µs No
times() \- No
clock() \- No (*) clock() \- No (*)
========================= =============== ============= ========================= =============== =============
@ -1032,16 +1038,18 @@ clock() SunOS 5.11 1 µs
getrusage() Linux 3.0 4 ms getrusage() Linux 3.0 4 ms
clock() FreeBSD 8.2 7.8 ms clock() FreeBSD 8.2 7.8 ms
clock() Linux 3.2 10 ms clock() Linux 3.2 10 ms
times() Linux 3.0 10 ms
clock() OpenBSD 5.0 10 ms clock() OpenBSD 5.0 10 ms
GetProcessTimes() Windows Seven 15.6 ms GetProcessTimes() Windows Seven 15.6 ms
========================= ================ =============== ========================= ================ ===============
The precision of clock() in this table is the result of 1 / The precision of clock() in this table is the result of 1 /
CLOCKS_PER_SEC. For CLOCK_PROCESS_CPUTIME_ID, the precision of this CLOCKS_PER_SEC. The precision of times() in this table is the result of 1 /
table is the result of clock_getres(). It looks like Linux does not HZ. HZ is a constant or read from sysconf(_SC_CLK_TCK). For
implement clock_getres() and always returns 1 nanosecond. For CLOCK_PROCESS_CPUTIME_ID, the precision of this table is the result of
GetProcessTimes(), the precision is read using clock_getres(). It looks like Linux does not implement clock_getres() and
GetSystemTimeAdjustment(). always returns 1 nanosecond. For GetProcessTimes(), the precision is read
using GetSystemTimeAdjustment().
Functions Functions