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qinsoon
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Jul 10, 2024
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| c.bench_function("internal pointer - normal objects", |_b| { |
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This is some data for this micro benchmark.
The naive implementation (find_prev_non_zero_value_simple, similar to #1155): check every aligned data address until we find the object.
internal pointer - normal objects
time: [12.910 µs 12.911 µs 12.912 µs]
internal pointer - large objects
time: [53.164 ns 53.486 ns 53.939 ns]Check every byte in side metadata until we find VO bit, and compute it back to the VO address
internal pointer - normal objects
time: [1.5500 µs 1.5504 µs 1.5509 µs]
change: [-88.001% -87.997% -87.994%] (p = 0.00 < 0.05)
Performance has improved.
internal pointer - large objects
time: [58.115 ns 58.137 ns 58.161 ns]
change: [+8.0877% +8.6753% +9.1317%] (p = 0.00 < 0.05)
Performance has regressed.Check every word in side metadata until we find VO bit, and compute it back to the VO address
internal pointer - normal objects
time: [311.28 ns 312.38 ns 313.51 ns]
change: [-79.856% -79.804% -79.741%] (p = 0.00 < 0.05)
Performance has improved.
internal pointer - large objects
time: [57.582 ns 57.607 ns 57.635 ns]
change: [-0.9006% -0.8311% -0.7566%] (p = 0.00 < 0.05)
Change within noise threshold.
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After applying the suggestion in #1165 (comment), we only check if the metadata address is mapped for every chunk. The performance is further improved.
internal pointer - normal objects
time: [139.48 ns 139.65 ns 139.82 ns]
change: [-55.524% -55.388% -55.250%] (p = 0.00 < 0.05)
Performance has improved.
internal pointer - large objects
time: [49.300 ns 49.361 ns 49.462 ns]
change: [-14.459% -14.367% -14.263%] (p = 0.00 < 0.05)
Performance has improved.
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Jul 15, 2024
find_object_from_internal_pointer to the is_mmtk_object module
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This PR adds internal pointer support. It supersedes #1155 which provides a simple but inefficient implementation for internal pointers. This PR is based on #1159 which adds requirements for object reference alignment.
This PR
memory_manager::find_object_from_internal_pointer