wehub-resource-sync
104 lines
3.2 KiB
C++
104 lines
3.2 KiB
C++
/* ******************************************************************************
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*
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*
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* This program and the accompanying materials are made available under the
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* terms of the Apache License, Version 2.0 which is available at
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* https://www.apache.org/licenses/LICENSE-2.0.
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*
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* See the NOTICE file distributed with this work for additional
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* information regarding copyright ownership.
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
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* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
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* License for the specific language governing permissions and limitations
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* under the License.
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*
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* SPDX-License-Identifier: Apache-2.0
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******************************************************************************/
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//
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// @author raver119@gmail.com, created on 6/30/2018
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// @author Yurii Shyrma (iuriish@yahoo.com)
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//
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#include <helpers/OmpLaunchHelper.h>
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#include <math/templatemath.h>
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#include <system/Environment.h>
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namespace sd {
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////////////////////////////////////////////////////////////////////////////////
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OmpLaunchHelper::OmpLaunchHelper(const LongType N, float desiredNumThreads) {
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auto maxItersPerThread = Environment::getInstance().elementwiseThreshold();
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if (N < maxItersPerThread)
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_numThreads = 1;
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else {
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#ifdef _OPENMP
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if (desiredNumThreads == -1)
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desiredNumThreads = omp_get_max_threads();
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else if (desiredNumThreads < 1)
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desiredNumThreads = 1;
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else
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desiredNumThreads = sd::math::sd_min<int>(omp_get_max_threads(), desiredNumThreads);
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#else
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desiredNumThreads = Environment::getInstance().maxThreads();
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#endif
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_numThreads = sd::math::sd_min<int>(N / maxItersPerThread, desiredNumThreads);
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}
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_itersPerThread = N / _numThreads;
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_remainder = N % _numThreads; // last thread may contain bigger number of iterations
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}
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LongType OmpLaunchHelper::betterSpan(LongType N) { return betterSpan(N, betterThreads(N)); }
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LongType OmpLaunchHelper::betterSpan(LongType N, LongType numThreads) {
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auto r = N % numThreads;
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auto t = N / numThreads;
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if (r == 0)
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return t;
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else {
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// breaks alignment
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return t + 1;
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}
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}
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int OmpLaunchHelper::betterThreads(LongType N) {
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#ifdef _OPENMP
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return betterThreads(N, omp_get_max_threads());
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#else
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return betterThreads(N, Environment::getInstance().maxThreads());
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;
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#endif
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}
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int OmpLaunchHelper::betterThreads(LongType N, int maxThreads) {
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auto t = Environment::getInstance().elementwiseThreshold();
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if (N < t)
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return 1;
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else {
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return static_cast<int>(sd::math::sd_min<LongType>(N / t, maxThreads));
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}
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}
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int OmpLaunchHelper::tadThreads(LongType tadLength, LongType numTads) {
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#ifdef _OPENMP
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auto maxThreads = omp_get_max_threads();
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#else
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auto maxThreads = Environment::getInstance().maxThreads();
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#endif
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// if there's only 1 thread allowed - nothing to do here
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if (maxThreads <= 1) return 1;
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auto totalLength = tadLength * numTads;
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// if array is tiny - no need to spawn any threeds
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if (totalLength < Environment::getInstance().elementwiseThreshold()) return 1;
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// by default we're spawning as many threads we can, but not more than number of TADs
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return sd::math::sd_min<int>(numTads, maxThreads);
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}
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} // namespace sd
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