opal: enable load-linked, store-conditional atomics for AArch64 #8412
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bosilca
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bwbarrett
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This PR updates the opal atomic code to allow the use of the AArch64 LL/SC instructions even when C11 atomics are enabled. This should provide for better atomic lifo/fifo performance on these systems. Performance on Apple Silicon (Late 2021 Mac Mini M1, 16GB): LL/SC: ``` Mac-mini:class hjelmn$ ./opal_lifo -t 1 Single thread test. Time: 0 s 13621 us 13 nsec/poppush Atomics thread finished. Time: 0 s 14375 us 14 nsec/poppush Atomics thread finished. Time: 0 s 154525 us 154 nsec/poppush Atomics thread finished. Time: 0 s 154661 us 154 nsec/poppush Atomics thread finished. Time: 0 s 156505 us 156 nsec/poppush Atomics thread finished. Time: 0 s 157013 us 157 nsec/poppush Atomics thread finished. Time: 0 s 157493 us 157 nsec/poppush Atomics thread finished. Time: 0 s 158275 us 158 nsec/poppush Atomics thread finished. Time: 0 s 158647 us 158 nsec/poppush Atomics thread finished. Time: 0 s 158973 us 158 nsec/poppush All threads finished. Thread count: 8 Time: 0 s 159023 us 19 nsec/poppush SUPPORT: OMPI Test Passed: opal_lifo_t: (7 tests) ``` ``` Mac-mini:class hjelmn$ ./opal_fifo Single thread test. Time: 0 s 7620 us 7 nsec/poppush Atomics thread finished. Time: 0 s 7918 us 7 nsec/poppush Atomics thread finished. Time: 0 s 76081 us 76 nsec/poppush Atomics thread finished. Time: 0 s 79458 us 79 nsec/poppush Atomics thread finished. Time: 0 s 84994 us 84 nsec/poppush Atomics thread finished. Time: 0 s 90103 us 90 nsec/poppush Atomics thread finished. Time: 0 s 90403 us 90 nsec/poppush Atomics thread finished. Time: 0 s 91280 us 91 nsec/poppush Atomics thread finished. Time: 0 s 92466 us 92 nsec/poppush Atomics thread finished. Time: 0 s 93835 us 93 nsec/poppush All threads finished. Thread count: 8 Time: 0 s 93916 us 11 nsec/poppush Exhaustive atomics thread finished. Popped 821530 items. Time: 0 s 107912 us 131 nsec/poppush Exhaustive atomics thread finished. Popped 810445 items. Time: 0 s 114695 us 141 nsec/poppush Exhaustive atomics thread finished. Popped 806449 items. Time: 0 s 116241 us 144 nsec/poppush Exhaustive atomics thread finished. Popped 813960 items. Time: 0 s 117182 us 143 nsec/poppush Exhaustive atomics thread finished. Popped 825230 items. Time: 0 s 118810 us 143 nsec/poppush Exhaustive atomics thread finished. Popped 826685 items. Time: 0 s 119486 us 144 nsec/poppush Exhaustive atomics thread finished. Popped 828373 items. Time: 0 s 120327 us 145 nsec/poppush Exhaustive atomics thread finished. Popped 830266 items. Time: 0 s 121114 us 145 nsec/poppush All threads finished. Thread count: 8 Time: 0 s 121186 us 15 nsec/poppush SUPPORT: OMPI Test Passed: opal_fifo_t: (8 tests) ``` CAS128: ``` Mac-mini:class hjelmn$ ./opal_lifo -t 1 Single thread test. Time: 0 s 25688 us 25 nsec/poppush Atomics thread finished. Time: 0 s 29322 us 29 nsec/poppush Atomics thread finished. Time: 4 s 57595 us 4057 nsec/poppush Atomics thread finished. Time: 4 s 151568 us 4151 nsec/poppush Atomics thread finished. Time: 4 s 162332 us 4162 nsec/poppush Atomics thread finished. Time: 4 s 173651 us 4173 nsec/poppush Atomics thread finished. Time: 4 s 176088 us 4176 nsec/poppush Atomics thread finished. Time: 4 s 178025 us 4178 nsec/poppush Atomics thread finished. Time: 4 s 178713 us 4178 nsec/poppush Atomics thread finished. Time: 4 s 178760 us 4178 nsec/poppush All threads finished. Thread count: 8 Time: 4 s 178830 us 522 nsec/poppush SUPPORT: OMPI Test Passed: opal_lifo_t: (7 tests) ``` ``` Mac-mini:class hjelmn$ ./opal_fifo Single thread test. Time: 0 s 7611 us 7 nsec/poppush Atomics thread finished. Time: 0 s 19256 us 19 nsec/poppush Atomics thread finished. Time: 2 s 555095 us 2555 nsec/poppush Atomics thread finished. Time: 2 s 562521 us 2562 nsec/poppush Atomics thread finished. Time: 2 s 570284 us 2570 nsec/poppush Atomics thread finished. Time: 2 s 570760 us 2570 nsec/poppush Atomics thread finished. Time: 2 s 571438 us 2571 nsec/poppush Atomics thread finished. Time: 2 s 573642 us 2573 nsec/poppush Atomics thread finished. Time: 2 s 575019 us 2575 nsec/poppush Atomics thread finished. Time: 2 s 575161 us 2575 nsec/poppush All threads finished. Thread count: 8 Time: 2 s 575231 us 321 nsec/poppush Exhaustive atomics thread finished. Popped 639525 items. Time: 1 s 828167 us 2858 nsec/poppush Exhaustive atomics thread finished. Popped 642578 items. Time: 1 s 840312 us 2863 nsec/poppush Exhaustive atomics thread finished. Popped 641617 items. Time: 1 s 846852 us 2878 nsec/poppush Exhaustive atomics thread finished. Popped 639283 items. Time: 1 s 849705 us 2893 nsec/poppush Exhaustive atomics thread finished. Popped 646423 items. Time: 1 s 851183 us 2863 nsec/poppush Exhaustive atomics thread finished. Popped 645146 items. Time: 1 s 851750 us 2870 nsec/poppush Exhaustive atomics thread finished. Popped 645428 items. Time: 1 s 852076 us 2869 nsec/poppush Exhaustive atomics thread finished. Popped 648267 items. Time: 1 s 852240 us 2857 nsec/poppush All threads finished. Thread count: 8 Time: 1 s 852359 us 231 nsec/poppush SUPPORT: OMPI Test Passed: opal_fifo_t: (8 tests) ``` About a 40x performance with the multi-threaded lifo/fifo tests. These are artificial benchmarks but give a reasonable idea of how these structures perform under heavy contention. Signed-off-by: Nathan Hjelm <[email protected]>
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This PR updates the opal atomic code to allow the use of the AArch64
LL/SC instructions even when C11 atomics are enabled. This should
provide for better atomic lifo/fifo performance on these systems.
Performance on Apple Silicon (Late 2021 Mac Mini M1, 16GB):
LL/SC:
CAS128:
About a 40x performance with the multi-threaded lifo/fifo tests.
These are artificial benchmarks but give a reasonable idea of
how these structures perform under heavy contention.
Signed-off-by: Nathan Hjelm [email protected]