FlatMap: Use SSE2 intrinstics #1616
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publixsubfan
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Arlie-Capps,
BradWhitlock,
bmhan12,
jcs15c,
kennyweiss,
rhornung67 and
white238
publixsubfan
added
Core
kennyweiss
reviewed
Jul 16, 2025
| #include "axom/core/ArrayView.hpp" | ||
| #include "axom/core/utilities/BitUtilities.hpp" | ||
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| #if defined(_MSC_VER) |
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Do we need to do anything special to get the intrinsics, e.g. compile with the -march flag?
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My understanding is that nothing special is required if Axom is compiled as a 64-bit library, since support for up to SSE2 is a part of the x86-64 spec. For 32-bit x86 systems, you would need to specify -march=....
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I confirmed with my changes from #1614 that I am using the new SSE2 intrinsics w/ the rzwhippet-clang host-config
bmhan12
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Jul 16, 2025
Arlie-Capps
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Very cool, Max. Thanks!
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@publixsubfan Nice work! |
rhornung67
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Jul 16, 2025
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Summary
When available, uses SSE2 operations for
GroupBucket::getEmptyBucket()andGroupBucket::visitHashBucket(). This should accelerate performance of lookup and non-batched insertion operations on the CPU.Performance
We see a roughly 3x performance bump at small numbers of elements, which drops to 2x at the 100k-900k element count, and to 1.3-1.5x at 1M-9M elements.