ZhennanQin commented on a change in pull request #15379: Use omp threads for
cpu data loader
URL: https://github.com/apache/incubator-mxnet/pull/15379#discussion_r299318132
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File path: src/io/iter_image_recordio_2.cc
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@@ -134,19 +134,25 @@ inline void ImageRecordIOParser2<DType>::Init(
record_param_.InitAllowUnknown(kwargs);
batch_param_.InitAllowUnknown(kwargs);
normalize_param_.InitAllowUnknown(kwargs);
+ PrefetcherParam prefetch_param;
+ prefetch_param.InitAllowUnknown(kwargs);
n_parsed_ = 0;
overflow = false;
rnd_.seed(kRandMagic + record_param_.seed);
int maxthread, threadget;
- #pragma omp parallel
- {
- // be conservative, set number of real cores
- maxthread = std::max(omp_get_num_procs(), 1);
- }
- param_.preprocess_threads = std::min(maxthread, param_.preprocess_threads);
- #pragma omp parallel num_threads(param_.preprocess_threads)
- {
- threadget = omp_get_num_threads();
+ if (prefetch_param.ctx == PrefetcherParam::CtxType::kCPU) {
+ threadget = engine::OpenMP::Get()->GetRecommendedOMPThreadCount();
Review comment:
No. For CPU optimized data loader, prefetching isn't happened.
Prefetching will flush cache, causing CPU op execution much slower. So for
CPU optimized data loader, the loader itself works as a normal operator, which
will be executed exclusively, utilizing all omp threads.
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