/* * 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/dispatch.h> instead of this file directly." #include <dispatch/base.h> // for HeaderDoc #endif __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__ __OSX_AVAILABLE_STARTING(__MAC_10_6,__IPHONE_4_0) DISPATCH_EXPORT DISPATCH_NONNULL2 DISPATCH_NOTHROW uint64_t dispatch_benchmark(size_t count, void (^block)(void)); #endif __OSX_AVAILABLE_STARTING(__MAC_10_6,__IPHONE_4_0) DISPATCH_EXPORT DISPATCH_NONNULL3 DISPATCH_NOTHROW uint64_t dispatch_benchmark_f(size_t count, void *ctxt, void (*func)(void *)); __END_DECLS #endif