64 lines
2.6 KiB
C
64 lines
2.6 KiB
C
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//
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// SPDX-License-Identifier: BSD-3-Clause
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// Copyright (c) Contributors to the OpenEXR Project.
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//
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#ifndef INCLUDED_IMF_THREADING_H
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#define INCLUDED_IMF_THREADING_H
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#include "ImfExport.h"
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#include "ImfNamespace.h"
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//-----------------------------------------------------------------------------
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//
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// Threading support for the OpenEXR library
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//
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// The OpenEXR library uses threads to perform reading and writing
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// of OpenEXR files in parallel. The thread that calls the library
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// always performs the actual file IO (this is usually the main
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// application thread) whereas a several worker threads perform
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// data compression and decompression. The number of worker
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// threads can be any non-negative value (a value of zero reverts
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// to single-threaded operation). As long as there is at least
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// one worker thread, file IO and compression can potentially be
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// done concurrently through pinelining. If there are two or more
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// worker threads, then pipelining as well as concurrent compression
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// of multiple blocks can be performed.
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//
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// Threading in the EXR library is controllable at two granularities:
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//
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// * The functions in this file query and control the total number
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// of worker threads, which will be created globally for the whole
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// library. Regardless of how many input or output files are
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// opened simultaneously, the library will use at most this number
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// of worker threads to perform all work. The default number of
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// global worker threads is zero (i.e. single-threaded operation;
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// everything happens in the thread that calls the library).
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//
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// * Furthermore, it is possible to set the number of threads that
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// each input or output file should keep busy. This number can
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// be explicitly set for each file. The default behavior is for
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// each file to try to occupy all worker threads in the library's
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// thread pool.
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//
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//-----------------------------------------------------------------------------
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OPENEXR_IMF_INTERNAL_NAMESPACE_HEADER_ENTER
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//-----------------------------------------------------------------------------
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// Return the number of Imf-global worker threads used for parallel
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// compression and decompression of OpenEXR files.
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//-----------------------------------------------------------------------------
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IMF_EXPORT int globalThreadCount ();
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//-----------------------------------------------------------------------------
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// Change the number of Imf-global worker threads
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//-----------------------------------------------------------------------------
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IMF_EXPORT void setGlobalThreadCount (int count);
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OPENEXR_IMF_INTERNAL_NAMESPACE_HEADER_EXIT
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#endif
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