1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
|
/*
* Copyright (c) 2008-2009 Apple Inc. All rights reserved.
*
* @APPLE_APACHE_LICENSE_HEADER_START@
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*
* @APPLE_APACHE_LICENSE_HEADER_END@
*/
/*
* IMPORTANT: This header file describes INTERNAL interfaces to libdispatch
* which are subject to change in future releases of Mac OS X. Any applications
* relying on these interfaces WILL break.
*/
#ifndef __DISPATCH_BENCHMARK__
#define __DISPATCH_BENCHMARK__
#ifndef __DISPATCH_INDIRECT__
#error "Please #include <dispatch/private.h> instead of this file directly."
#include <dispatch/base.h> // for HeaderDoc
#endif
DISPATCH_ASSUME_NONNULL_BEGIN
__BEGIN_DECLS
/*!
* @function dispatch_benchmark
*
* @abstract
* Count the average number of cycles a given block takes to execute.
*
* @param count
* The number of times to serially execute the given block.
*
* @param block
* The block to execute.
*
* @result
* The approximate number of cycles the block takes to execute.
*
* @discussion
* This function is for debugging and performance analysis work. For the best
* results, pass a high count value to dispatch_benchmark(). When benchmarking
* concurrent code, please compare the serial version of the code against the
* concurrent version, and compare the concurrent version on different classes
* of hardware. Please look for inflection points with various data sets and
* keep the following facts in mind:
*
* 1) Code bound by computational bandwidth may be inferred by proportional
* changes in performance as concurrency is increased.
* 2) Code bound by memory bandwidth may be inferred by negligible changes in
* performance as concurrency is increased.
* 3) Code bound by critical sections may be inferred by retrograde changes in
* performance as concurrency is increased.
* 3a) Intentional: locks, mutexes, and condition variables.
* 3b) Accidental: unrelated and frequently modified data on the same
* cache-line.
*/
#ifdef __BLOCKS__
API_AVAILABLE(macos(10.6), ios(4.0))
DISPATCH_EXPORT DISPATCH_NONNULL2 DISPATCH_NOTHROW
uint64_t
dispatch_benchmark(size_t count, dispatch_block_t block);
#endif
API_AVAILABLE(macos(10.6), ios(4.0))
DISPATCH_EXPORT DISPATCH_NONNULL3 DISPATCH_NOTHROW
uint64_t
dispatch_benchmark_f(size_t count, void *_Nullable ctxt,
dispatch_function_t func);
__END_DECLS
DISPATCH_ASSUME_NONNULL_END
#endif
|
