On Tue, 29 Apr 2025 15:10:10 GMT, fabioromano1 <d...@openjdk.org> wrote:
>> This PR optimizes `BigInteger.pow(int)` method. The primary enhancement in
>> `pow()` is not concerned most on execution time, but rather in memory
>> optimization, because the PR implementation does the "shift of the exponent"
>> squaring the result rather than the base, so the base is not squared like in
>> the current implementation, and this permits to save about half of the
>> memory.
>
> fabioromano1 has updated the pull request incrementally with two additional
> commits since the last revision:
>
> - Adjust the type of operand
> - Use a more loose formula to do range check
>
> Use a more loose formula to do range check, in order not to exclude a
> priori values that may be inside the supported range
I don't observe any significant difference on my environment
macOS 15.4.1 / M1 Pro / 32 GiB / java 25-internal
before
----
Benchmark Mode Cnt Score
Error Units
BigIntegerPow.testPowL avgt 3 7466740027.667 ±
1815231444.569 ns/op
BigIntegerPow.testPowL:gc.alloc.rate avgt 3 3964.967 ±
970.175 MB/sec
BigIntegerPow.testPowL:gc.alloc.rate.norm avgt 3 31040625701.333 ±
337.057 B/op
BigIntegerPow.testPowL:gc.count avgt 3 201.000
counts
BigIntegerPow.testPowL:gc.time avgt 3 145.000
ms
BigIntegerPow.testPowM avgt 3 5281109916.667 ±
1387864024.559 ns/op
BigIntegerPow.testPowM:gc.alloc.rate avgt 3 3718.944 ±
968.869 MB/sec
BigIntegerPow.testPowM:gc.alloc.rate.norm avgt 3 20592088429.333 ±
337.057 B/op
BigIntegerPow.testPowM:gc.count avgt 3 135.000
counts
BigIntegerPow.testPowM:gc.time avgt 3 98.000
ms
BigIntegerPow.testPowS avgt 3 5195628500.333 ±
738936923.575 ns/op
BigIntegerPow.testPowS:gc.alloc.rate avgt 3 3758.710 ±
534.778 MB/sec
BigIntegerPow.testPowS:gc.alloc.rate.norm avgt 3 20477396224.000 ±
0.001 B/op
BigIntegerPow.testPowS:gc.count avgt 3 135.000
counts
BigIntegerPow.testPowS:gc.time avgt 3 94.000
ms
BigIntegerPow.testPowXL avgt 3 8125774666.667 ±
1137294539.763 ns/op
BigIntegerPow.testPowXL:gc.alloc.rate avgt 3 4120.707 ±
577.639 MB/sec
BigIntegerPow.testPowXL:gc.alloc.rate.norm avgt 3 35109921325.333 ±
337.057 B/op
BigIntegerPow.testPowXL:gc.count avgt 3 231.000
counts
BigIntegerPow.testPowXL:gc.time avgt 3 161.000
ms
BigIntegerPow.testPowXS avgt 3 4631164917.000 ±
354282119.389 ns/op
BigIntegerPow.testPowXS:gc.alloc.rate avgt 3 3879.394 ±
297.057 MB/sec
BigIntegerPow.testPowXS:gc.alloc.rate.norm avgt 3 18839312808.000 ±
0.001 B/op
BigIntegerPow.testPowXS:gc.count avgt 3 124.000
counts
BigIntegerPow.testPowXS:gc.time avgt 3 85.000
ms
after
----
Benchmark Mode Cnt Score
Error Units
BigIntegerPow.testPowL avgt 3 7502352027.667 ±
1599949168.779 ns/op
BigIntegerPow.testPowL:gc.alloc.rate avgt 3 3946.047 ±
845.736 MB/sec
BigIntegerPow.testPowL:gc.alloc.rate.norm avgt 3 31040625690.667 ±
337.057 B/op
BigIntegerPow.testPowL:gc.count avgt 3 202.000
counts
BigIntegerPow.testPowL:gc.time avgt 3 143.000
ms
BigIntegerPow.testPowM avgt 3 5269442569.333 ±
869646901.137 ns/op
BigIntegerPow.testPowM:gc.alloc.rate avgt 3 3724.365 ±
638.773 MB/sec
BigIntegerPow.testPowM:gc.alloc.rate.norm avgt 3 20578167389.333 ±
439892039.777 B/op
BigIntegerPow.testPowM:gc.count avgt 3 135.000
counts
BigIntegerPow.testPowM:gc.time avgt 3 93.000
ms
BigIntegerPow.testPowS avgt 3 5186210888.667 ±
723686794.493 ns/op
BigIntegerPow.testPowS:gc.alloc.rate avgt 3 3765.528 ±
523.216 MB/sec
BigIntegerPow.testPowS:gc.alloc.rate.norm avgt 3 20477396224.000 ±
0.001 B/op
BigIntegerPow.testPowS:gc.count avgt 3 134.000
counts
BigIntegerPow.testPowS:gc.time avgt 3 94.000
ms
BigIntegerPow.testPowXL avgt 3 8153839055.667 ±
1004638585.690 ns/op
BigIntegerPow.testPowXL:gc.alloc.rate avgt 3 4106.489 ±
506.894 MB/sec
BigIntegerPow.testPowXL:gc.alloc.rate.norm avgt 3 35109921325.333 ±
337.057 B/op
BigIntegerPow.testPowXL:gc.count avgt 3 230.000
counts
BigIntegerPow.testPowXL:gc.time avgt 3 158.000
ms
BigIntegerPow.testPowXS avgt 3 4588205708.333 ±
312969172.545 ns/op
BigIntegerPow.testPowXS:gc.alloc.rate avgt 3 3915.690 ±
266.340 MB/sec
BigIntegerPow.testPowXS:gc.alloc.rate.norm avgt 3 18839312829.333 ±
337.057 B/op
BigIntegerPow.testPowXS:gc.count avgt 3 123.000
counts
BigIntegerPow.testPowXS:gc.time avgt 3 83.000
ms
-------------
PR Comment: https://git.openjdk.org/jdk/pull/24690#issuecomment-2839390637
