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 72 namespace 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 80 int globalThreadCount (); 81 82 83 //----------------------------------------------------------------------------- 84 // Change the number of Imf-global worker threads 85 //----------------------------------------------------------------------------- 86 87 void setGlobalThreadCount (int count); 88 89 90 } // namespace Imf 91 92 #endif 93
