Implement exponential backoff in spinlock #2391
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Summary: SB (Speculation Barrier) is a modern barrier, mandatory from armv8.5a. It achieves the same result as issuing DSB+ISB, but without having the cpu drop its instruction pipeline. We have noticed 20% to 30% increased throughput, on the 16, 32 and 64 thread-count case within the small locks benchmark. In the below results, 'Sum' is throughput: before: ------- folly::MicroSpinLock 16 threads Sum: 130891978 Mean: 1817944 stddev: 147111 Lock time stats in us: mean 1 stddev 33 max 14937 ------- folly::MicroSpinLock 32 threads Sum: 54681548 Mean: 759465 stddev: 105588 Lock time stats in us: mean 5 stddev 78 max 35925 ------- folly::MicroSpinLock 64 threads Sum: 24013546 Mean: 333521 stddev: 90571 Lock time stats in us: mean 11 stddev 179 max 90498 after: ------- folly::MicroSpinLock 16 threads Sum: 169135465 Mean: 2349103 stddev: 227369 Lock time stats in us: mean 1 stddev 25 max 8463 ------- folly::MicroSpinLock 32 threads Sum: 67853388 Mean: 942408 stddev: 108821 Lock time stats in us: mean 3 stddev 63 max 17020 ------- folly::MicroSpinLock 64 threads Sum: 28845120 Mean: 400626 stddev: 61624 Lock time stats in us: mean 9 stddev 149 max 30879 Reviewed By: Gownta Differential Revision: D70250662
Summary: Implement exponential backoff in spinlocks runniong on ARM, as suggested by: https://community.arm.com/arm-community-blogs/b/architectures-and-processors-blog/posts/multi-threaded-applications-arm We have noticed throughput almost doubles, on the 32 and 64 thread-count cases within the small locks benchmark. In the below results, 'Sum' is throughput: before: ------- folly::MicroSpinLock 32 threads Sum: 67853388 Mean: 942408 stddev: 108821 Lock time stats in us: mean 3 stddev 63 max 17020 ------- folly::MicroSpinLock 64 threads Sum: 28845120 Mean: 400626 stddev: 61624 Lock time stats in us: mean 9 stddev 149 max 30879 after: ------- folly::MicroSpinLock 32 threads Sum: 116020339 Mean: 1611393 stddev: 27242 Lock time stats in us: mean 1 stddev 3 max 8394 ------- folly::MicroSpinLock 64 threads Sum: 54264302 Mean: 753670 stddev: 30988 Lock time stats in us: mean 4 stddev 3 max 12924 Reviewed By: Gownta Differential Revision: D70250664
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This pull request was exported from Phabricator. Differential Revision: D70250664 |
Nicoshev
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Feb 26, 2025
Summary: X-link: facebook/folly#2391 Implement exponential backoff in spinlocks runniong on ARM, as suggested by: https://community.arm.com/arm-community-blogs/b/architectures-and-processors-blog/posts/multi-threaded-applications-arm We have noticed throughput almost doubles, on the 32 and 64 thread-count cases within the small locks benchmark. In the below results, 'Sum' is throughput: before: ------- folly::MicroSpinLock 32 threads Sum: 67853388 Mean: 942408 stddev: 108821 Lock time stats in us: mean 3 stddev 63 max 17020 ------- folly::MicroSpinLock 64 threads Sum: 28845120 Mean: 400626 stddev: 61624 Lock time stats in us: mean 9 stddev 149 max 30879 after: ------- folly::MicroSpinLock 32 threads Sum: 116020339 Mean: 1611393 stddev: 27242 Lock time stats in us: mean 1 stddev 3 max 8394 ------- folly::MicroSpinLock 64 threads Sum: 54264302 Mean: 753670 stddev: 30988 Lock time stats in us: mean 4 stddev 3 max 12924 Reviewed By: Gownta Differential Revision: D70250664
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This pull request has been merged in 48940bb. |
facebook-github-bot
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Feb 27, 2025
Summary: Pull Request resolved: #9592 X-link: facebook/folly#2391 Implement exponential backoff in spinlocks runniong on ARM, as suggested by: https://community.arm.com/arm-community-blogs/b/architectures-and-processors-blog/posts/multi-threaded-applications-arm We have noticed throughput almost doubles, on the 32 and 64 thread-count cases within the small locks benchmark. In the below results, 'Sum' is throughput: before: ------- folly::MicroSpinLock 32 threads Sum: 67853388 Mean: 942408 stddev: 108821 Lock time stats in us: mean 3 stddev 63 max 17020 ------- folly::MicroSpinLock 64 threads Sum: 28845120 Mean: 400626 stddev: 61624 Lock time stats in us: mean 9 stddev 149 max 30879 after: ------- folly::MicroSpinLock 32 threads Sum: 116020339 Mean: 1611393 stddev: 27242 Lock time stats in us: mean 1 stddev 3 max 8394 ------- folly::MicroSpinLock 64 threads Sum: 54264302 Mean: 753670 stddev: 30988 Lock time stats in us: mean 4 stddev 3 max 12924 Reviewed By: Gownta Differential Revision: D70250664 fbshipit-source-id: 7277fee05b451dafb5e8d61240efd138636b4684
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Summary:
Implement exponential backoff in spinlocks runniong on ARM, as suggested by: https://community.arm.com/arm-community-blogs/b/architectures-and-processors-blog/posts/multi-threaded-applications-arm
We have noticed throughput almost doubles, on the 32 and 64 thread-count cases within the small locks benchmark.
In the below results, 'Sum' is throughput:
before:
------- folly::MicroSpinLock 32 threads
Sum: 67853388 Mean: 942408 stddev: 108821
Lock time stats in us: mean 3 stddev 63 max 17020
------- folly::MicroSpinLock 64 threads
Sum: 28845120 Mean: 400626 stddev: 61624
Lock time stats in us: mean 9 stddev 149 max 30879
after:
------- folly::MicroSpinLock 32 threads
Sum: 116020339 Mean: 1611393 stddev: 27242
Lock time stats in us: mean 1 stddev 3 max 8394
------- folly::MicroSpinLock 64 threads
Sum: 54264302 Mean: 753670 stddev: 30988
Lock time stats in us: mean 4 stddev 3 max 12924
Reviewed By: Gownta
Differential Revision: D70250664