29 lines
1.1 KiB
Diff
29 lines
1.1 KiB
Diff
commit d9a5f9d9db092cc5b4d8fd563a834183b2e9b301
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Author: Joseph Schuchart <joseph.schuchart@stonybrook.edu>
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Date: Wed May 28 10:11:58 2025 -0400
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Force alignment of opal_atomic_int128_t to be 16B
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Some architectures will align 128bit integer on 8B but require 16B alignment
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for 128bit CAS instructions and otherwise fall back to a lock-based
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atomicity model. By forcing 16bit alignment we can ensure that the variables
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are properly aligned and the fall-back is not triggered.
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Thanks to Ulrich Weigand for the analysis and proposed fix in https://github.com/open-mpi/ompi/issues/10988#issuecomment-2913388506.
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Signed-off-by: Joseph Schuchart <joseph.schuchart@stonybrook.edu>
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diff --git opal/include/opal_stdatomic.h opal/include/opal_stdatomic.h
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index 354375512088..f7dd8353d3b6 100644
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--- opal/include/opal_stdatomic.h
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+++ opal/include/opal_stdatomic.h
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@@ -72,7 +72,7 @@ typedef _Atomic opal_int128_t opal_atomic_int128_t;
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# else
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-typedef volatile opal_int128_t opal_atomic_int128_t;
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+typedef volatile opal_int128_t opal_atomic_int128_t __opal_attribute_aligned__(16);
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# endif
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