1# encoding: utf-8
2"""
3Utilities for timing code execution.
4"""
5
6#-----------------------------------------------------------------------------
7# Copyright (C) 2008-2011 The IPython Development Team
8#
9# Distributed under the terms of the BSD License. The full license is in
10# the file COPYING, distributed as part of this software.
11#-----------------------------------------------------------------------------
12
13#-----------------------------------------------------------------------------
14# Imports
15#-----------------------------------------------------------------------------
16
17import time
18
19#-----------------------------------------------------------------------------
20# Code
21#-----------------------------------------------------------------------------
22
23# If possible (Unix), use the resource module instead of time.clock()
24try:
25 import resource
26except ModuleNotFoundError:
27 resource = None # type: ignore [assignment]
28
29# Some implementations (like jyputerlite) don't have getrusage
30if resource is not None and hasattr(resource, "getrusage"):
31 def clocku():
32 """clocku() -> floating point number
33
34 Return the *USER* CPU time in seconds since the start of the process.
35 This is done via a call to resource.getrusage, so it avoids the
36 wraparound problems in time.clock()."""
37
38 return resource.getrusage(resource.RUSAGE_SELF)[0]
39
40 def clocks():
41 """clocks() -> floating point number
42
43 Return the *SYSTEM* CPU time in seconds since the start of the process.
44 This is done via a call to resource.getrusage, so it avoids the
45 wraparound problems in time.clock()."""
46
47 return resource.getrusage(resource.RUSAGE_SELF)[1]
48
49 def clock():
50 """clock() -> floating point number
51
52 Return the *TOTAL USER+SYSTEM* CPU time in seconds since the start of
53 the process. This is done via a call to resource.getrusage, so it
54 avoids the wraparound problems in time.clock()."""
55
56 u,s = resource.getrusage(resource.RUSAGE_SELF)[:2]
57 return u+s
58
59 def clock2():
60 """clock2() -> (t_user,t_system)
61
62 Similar to clock(), but return a tuple of user/system times."""
63 return resource.getrusage(resource.RUSAGE_SELF)[:2]
64
65else:
66 # There is no distinction of user/system time under windows, so we just use
67 # time.process_time() for everything...
68 clocku = clocks = clock = time.process_time
69
70 def clock2():
71 """Under windows, system CPU time can't be measured.
72
73 This just returns process_time() and zero."""
74 return time.process_time(), 0.0
75
76
77def timings_out(reps,func,*args,**kw):
78 """timings_out(reps,func,*args,**kw) -> (t_total,t_per_call,output)
79
80 Execute a function reps times, return a tuple with the elapsed total
81 CPU time in seconds, the time per call and the function's output.
82
83 Under Unix, the return value is the sum of user+system time consumed by
84 the process, computed via the resource module. This prevents problems
85 related to the wraparound effect which the time.clock() function has.
86
87 Under Windows the return value is in wall clock seconds. See the
88 documentation for the time module for more details."""
89
90 reps = int(reps)
91 assert reps >=1, 'reps must be >= 1'
92 if reps==1:
93 start = clock()
94 out = func(*args,**kw)
95 tot_time = clock()-start
96 else:
97 rng = range(reps-1) # the last time is executed separately to store output
98 start = clock()
99 for dummy in rng: func(*args,**kw)
100 out = func(*args,**kw) # one last time
101 tot_time = clock()-start
102 av_time = tot_time / reps
103 return tot_time,av_time,out
104
105
106def timings(reps,func,*args,**kw):
107 """timings(reps,func,*args,**kw) -> (t_total,t_per_call)
108
109 Execute a function reps times, return a tuple with the elapsed total CPU
110 time in seconds and the time per call. These are just the first two values
111 in timings_out()."""
112
113 return timings_out(reps,func,*args,**kw)[0:2]
114
115
116def timing(func,*args,**kw):
117 """timing(func,*args,**kw) -> t_total
118
119 Execute a function once, return the elapsed total CPU time in
120 seconds. This is just the first value in timings_out()."""
121
122 return timings_out(1,func,*args,**kw)[0]
123