1 /* 2 * Copyright (c) 2008-2009 Apple Inc. All rights reserved. 3 * 4 * @APPLE_APACHE_LICENSE_HEADER_START@ 5 * 6 * Licensed under the Apache License, Version 2.0 (the "License"); 7 * you may not use this file except in compliance with the License. 8 * You may obtain a copy of the License at 9 * 10 * http://www.apache.org/licenses/LICENSE-2.0 11 * 12 * Unless required by applicable law or agreed to in writing, software 13 * distributed under the License is distributed on an "AS IS" BASIS, 14 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 15 * See the License for the specific language governing permissions and 16 * limitations under the License. 17 * 18 * @APPLE_APACHE_LICENSE_HEADER_END@ 19 */ 20 21 /* 22 * IMPORTANT: This header file describes INTERNAL interfaces to libdispatch 23 * which are subject to change in future releases of Mac OS X. Any applications 24 * relying on these interfaces WILL break. 25 */ 26 27 #ifndef __DISPATCH_BENCHMARK__ 28 #define __DISPATCH_BENCHMARK__ 29 30 #ifndef __DISPATCH_INDIRECT__ 31 #error "Please #include <dispatch/private.h> instead of this file directly." 32 #include <dispatch/base.h> // for HeaderDoc 33 #endif 34 35 __BEGIN_DECLS 36 37 /*! 38 * @function dispatch_benchmark 39 * 40 * @abstract 41 * Count the average number of cycles a given block takes to execute. 42 * 43 * @param count 44 * The number of times to serially execute the given block. 45 * 46 * @param block 47 * The block to execute. 48 * 49 * @result 50 * The approximate number of cycles the block takes to execute. 51 * 52 * @discussion 53 * This function is for debugging and performance analysis work. For the best 54 * results, pass a high count value to dispatch_benchmark(). When benchmarking 55 * concurrent code, please compare the serial version of the code against the 56 * concurrent version, and compare the concurrent version on different classes 57 * of hardware. Please look for inflection points with various data sets and 58 * keep the following facts in mind: 59 * 60 * 1) Code bound by computational bandwidth may be inferred by proportional 61 * changes in performance as concurrency is increased. 62 * 2) Code bound by memory bandwidth may be inferred by negligible changes in 63 * performance as concurrency is increased. 64 * 3) Code bound by critical sections may be inferred by retrograde changes in 65 * performance as concurrency is increased. 66 * 3a) Intentional: locks, mutexes, and condition variables. 67 * 3b) Accidental: unrelated and frequently modified data on the same 68 * cache-line. 69 */ 70 #ifdef __BLOCKS__ 71 __OSX_AVAILABLE_STARTING(__MAC_10_6,__IPHONE_4_0) 72 DISPATCH_EXPORT DISPATCH_NONNULL2 DISPATCH_NOTHROW 73 uint64_t 74 dispatch_benchmark(size_t count, void (^block)(void)); 75 #endif 76 77 __OSX_AVAILABLE_STARTING(__MAC_10_6,__IPHONE_4_0) 78 DISPATCH_EXPORT DISPATCH_NONNULL3 DISPATCH_NOTHROW 79 uint64_t 80 dispatch_benchmark_f(size_t count, void *ctxt, void (*func)(void *)); 81 82 __END_DECLS 83 84 #endif 85