RFR: 8310843: Reimplement ByteArray and ByteArrayLittleEndian with Unsafe [v10]

[Glavo]

On Thu, 20 Jul 2023 16:24:09 GMT, Maurizio Cimadamore <mcimadamore at openjdk.org> wrote:

> Here's with the same parameters as the one you are using:

I don't understand why there is such a difference. I have replicated similar results on several other devices:

Apple M1:

Benchmark                      Mode  Cnt        Score       Error   Units
ByteArray.readByte            thrpt    5  1418606.665 ±  2308.711  ops/ms
ByteArray.readByteFromBuffer  thrpt    5   879084.678 ± 20981.303  ops/ms
ByteArray.readInt             thrpt    5  1404164.063 ±  4845.412  ops/ms
ByteArray.readIntFromBuffer   thrpt    5   829768.843 ±  8730.467  ops/ms
ByteArray.readLong            thrpt    5  1400713.660 ±  1924.752  ops/ms
ByteArray.readLongFromBuffer  thrpt    5   825721.508 ±  4146.961  ops/ms



Intel Celeron N5105:

Benchmark                      Mode  Cnt       Score        Error   Units
ByteArray.readByte            thrpt    5  927248.807 ±  29630.442  ops/ms
ByteArray.readByteFromBuffer  thrpt    5  448374.359 ±   3210.571  ops/ms
ByteArray.readInt             thrpt    5  719143.935 ± 183584.747  ops/ms
ByteArray.readIntFromBuffer   thrpt    5  398578.488 ±    100.058  ops/ms
ByteArray.readLong            thrpt    5  742555.147 ±  13006.710  ops/ms
ByteArray.readLongFromBuffer  thrpt    5  398771.660 ±   1673.524  ops/ms


AMD Ryzen 7 5800X:

Benchmark                      Mode  Cnt        Score       Error   Units
ByteArray.readByte            thrpt    5  1784096.905 ± 47611.535  ops/ms
ByteArray.readByteFromBuffer  thrpt    5   992974.747 ± 19389.011  ops/ms
ByteArray.readInt             thrpt    5  1719368.129 ± 70606.284  ops/ms
ByteArray.readIntFromBuffer   thrpt    5   919654.075 ±  9292.283  ops/ms
ByteArray.readLong            thrpt    5  1719873.280 ± 18441.122  ops/ms
ByteArray.readLongFromBuffer  thrpt    5   921992.992 ±  6439.747  ops/ms

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PR Review Comment: https://git.openjdk.org/jdk/pull/14636#discussion_r1269714639