1/////////////////////////////////////////////////////////////////////////// 2// 3// Copyright (c) 2005, Industrial Light & Magic, a division of Lucas 4// Digital Ltd. LLC 5// 6// All rights reserved. 7// 8// Redistribution and use in source and binary forms, with or without 9// modification, are permitted provided that the following conditions are 10// met: 11// * Redistributions of source code must retain the above copyright 12// notice, this list of conditions and the following disclaimer. 13// * Redistributions in binary form must reproduce the above 14// copyright notice, this list of conditions and the following disclaimer 15// in the documentation and/or other materials provided with the 16// distribution. 17// * Neither the name of Industrial Light & Magic nor the names of 18// its contributors may be used to endorse or promote products derived 19// from this software without specific prior written permission. 20// 21// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS 22// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 23// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR 24// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT 25// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, 26// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT 27// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 28// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 29// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 30// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE 31// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 32// 33/////////////////////////////////////////////////////////////////////////// 34 35#ifndef INCLUDED_IMF_THREADING_H 36#define INCLUDED_IMF_THREADING_H 37 38//----------------------------------------------------------------------------- 39// 40// Threading support for the IlmImf library 41// 42// The IlmImf library uses threads to perform reading and writing 43// of OpenEXR files in parallel. The thread that calls the library 44// always performs the actual file IO (this is usually the main 45// application thread) whereas a several worker threads perform 46// data compression and decompression. The number of worker 47// threads can be any non-negative value (a value of zero reverts 48// to single-threaded operation). As long as there is at least 49// one worker thread, file IO and compression can potentially be 50// done concurrently through pinelining. If there are two or more 51// worker threads, then pipelining as well as concurrent compression 52// of multiple blocks can be performed. 53// 54// Threading in the Imf library is controllable at two granularities: 55// 56// * The functions in this file query and control the total number 57// of worker threads, which will be created globally for the whole 58// library. Regardless of how many input or output files are 59// opened simultaneously, the library will use at most this number 60// of worker threads to perform all work. The default number of 61// global worker threads is zero (i.e. single-threaded operation; 62// everything happens in the thread that calls the library). 63// 64// * Furthermore, it is possible to set the number of threads that 65// each input or output file should keep busy. This number can 66// be explicitly set for each file. The default behavior is for 67// each file to try to occupy all worker threads in the library's 68// thread pool. 69// 70//----------------------------------------------------------------------------- 71 72namespace Imf { 73 74 75//----------------------------------------------------------------------------- 76// Return the number of Imf-global worker threads used for parallel 77// compression and decompression of OpenEXR files. 78//----------------------------------------------------------------------------- 79 80int globalThreadCount (); 81 82 83//----------------------------------------------------------------------------- 84// Change the number of Imf-global worker threads 85//----------------------------------------------------------------------------- 86 87void setGlobalThreadCount (int count); 88 89 90} // namespace Imf 91 92#endif 93