v2.x: opal/asm: work around possible gcc compiler bug #6047
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It seems in some cases (gcc older than v6.0.0) the __atomic_thread_fence is a no-op with __ATOMIC_ACQUIRE. This appears to be the case with X86_64 so go ahead and use __ATOMIC_SEQ_CST for the x86_64 read memory barrier. This should not cause any performance issues as it is equivalent to the memory barrier in the hand-written atomics. References open-mpi#6014 Signed-off-by: Nathan Hjelm <[email protected]> (cherry picked from commit 30119ee) Signed-off-by: Nathan Hjelm <[email protected]>
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Just for completeness. |
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bot:ompi:retest |
jsquyres
changed the title
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@hppritcha Good to go. |
jsquyres
approved these changes
Nov 26, 2018
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It seems in some cases (gcc older than v6.0.0) the __atomic_thread_fence is a
no-op with __ATOMIC_ACQUIRE. This appears to be the case with X86_64 so go
ahead and use __ATOMIC_SEQ_CST for the x86_64 read memory barrier. This should
not cause any performance issues as it is equivalent to the memory barrier
in the hand-written atomics.
References #6014
Signed-off-by: Nathan Hjelm [email protected]
(cherry picked from commit 30119ee)
Signed-off-by: Nathan Hjelm [email protected]