diff options
| author | Jacques Lucke <jacques@blender.org> | 2021-12-02 14:54:35 +0300 |
|---|---|---|
| committer | Jacques Lucke <jacques@blender.org> | 2021-12-02 14:56:47 +0300 |
| commit | e1309030603980c6b2f33486adf6ae5c2e4eb965 (patch) | |
| tree | eebf8666d6ab20a75b3bae4299eac12bf0b161fa /source/blender/blenlib | |
| parent | 0f89d05848b8a279ac6507404dc535244cd73d43 (diff) | |
BLI: avoid invoking tbb for small workloads
We often call `parallel_for` in places with very variable
sized workloads. When many elements are processed,
using multi-threading is great, but when processing
few elements (possibly many times) using `parallel_for`
can result in significant overhead.
I measured that this improves performance by >20% in
the refactored realize instances code I'm working on
separately. The change might also help with debugging
sometimes, because the stack trace is smaller and contains
fewer irrevelant symbols.
Diffstat (limited to 'source/blender/blenlib')
| -rw-r--r-- | source/blender/blenlib/BLI_task.hh | 15 |
1 files changed, 10 insertions, 5 deletions
diff --git a/source/blender/blenlib/BLI_task.hh b/source/blender/blenlib/BLI_task.hh index da7309837c8..84d5cd39bb4 100644 --- a/source/blender/blenlib/BLI_task.hh +++ b/source/blender/blenlib/BLI_task.hh @@ -67,14 +67,19 @@ void parallel_for(IndexRange range, int64_t grain_size, const Function &function return; } #ifdef WITH_TBB - tbb::parallel_for(tbb::blocked_range<int64_t>(range.first(), range.one_after_last(), grain_size), - [&](const tbb::blocked_range<int64_t> &subrange) { - function(IndexRange(subrange.begin(), subrange.size())); - }); + /* Invoking tbb for small workloads has a large overhead. */ + if (range.size() >= grain_size) { + tbb::parallel_for( + tbb::blocked_range<int64_t>(range.first(), range.one_after_last(), grain_size), + [&](const tbb::blocked_range<int64_t> &subrange) { + function(IndexRange(subrange.begin(), subrange.size())); + }); + return; + } #else UNUSED_VARS(grain_size); - function(range); #endif + function(range); } template<typename Value, typename Function, typename Reduction> |