On Thu, 31 Oct 2024 17:23:51 GMT, Quan Anh Mai <qa...@openjdk.org> wrote:
>> Hi,
>>
>> This patch makes `MemorySessionImpl.state` a `Stable` field so that liveness
>> check of non-closeable scopes such as the global scope can be elided.
>>
>> Currently, the `state` field is overloaded with 2 responsibilities, to act
>> as a communication device between `close` and `checkValidState`, as well as
>> a communication device between `close`, `acquire`, and `release`. This patch
>> separates those concerns into `state` and `acquireCount`, allowing `state`
>> to be marked as `@Stable`.
>>
>> With the patch, in `MemorySegmentGetUnsafe`, `panama` is able to be on par
>> with `unsafe`:
>>
>> Benchmark Mode Cnt Score Error Units
>> MemorySegmentGetUnsafe.panama avgt 30 0.340 ± 0.008 ns/op
>> MemorySegmentGetUnsafe.unsafe avgt 30 0.332 ± 0.004 ns/op
>>
>> For reference this is the results without this patch:
>>
>> Benchmark Mode Cnt Score Error Units
>> MemorySegmentGetUnsafe.panama avgt 30 0.420 ± 0.019 ns/op
>> MemorySegmentGetUnsafe.unsafe avgt 30 0.329 ± 0.003 ns/op
>>
>> Please kindly review, thanks very much.
>
> Quan Anh Mai has updated the pull request incrementally with one additional
> commit since the last revision:
>
> add LoopOverRandom benchmarks
The result of the new benchmark by @mcimadamore , the patch offers an
improvement in the `segment_loop_all` and `segment_loop_asUnchecked` cases. For
some reasons, the compiler really dislikes the unsafe loop.
Before After
Benchmark Mode Cnt Score Error Score
Error Units
LoopOverRandom.segment_loop avgt 30 2.218 ± 0.007 2.261 ±
0.096 us/op
LoopOverRandom.segment_loop_all avgt 30 1.958 ± 0.007 1.917 ±
0.005 us/op
LoopOverRandom.segment_loop_asUnchecked avgt 30 1.834 ± 0.005 1.747 ±
0.004 us/op
LoopOverRandom.unsafe_loop avgt 30 1.825 ± 0.026 1.795 ±
0.004 us/op
-------------
PR Comment: https://git.openjdk.org/jdk/pull/21810#issuecomment-2450429727
