RFR: 8343629: More MergeStore benchmark

[Shaojin Wen]

On Wed, 6 Nov 2024 07:22:40 GMT, Emanuel Peter <epeter at openjdk.org> wrote:

>> 1. Added the putBytes4 benchmark, which corresponds to StringBuilder appendNull
>> 2. Optimized the putChars4/setInt/setLong series of benchmarks to reduce extra overhead and more accurately reflect performance differences.
>
> You can find an example of how to do that easily here:
> https://github.com/openjdk/jdk/pull/19970/files#diff-9072c369f5b541ef9fca3ad8320aa59e88cc72f203c03da58100b1d111ffc324R746-R749

@eme64 Why is there no noticeable difference in the performance of `+/-MergeStores`

|   | -MergeStores  | +MergeStores | delta |
| --- | --- | --- | --- |
| getCharB | 5900.246 | 5902.316 | -0.04% |
| getCharBU | 4865.881 | 4866.630 | -0.02% |
| getCharBV | 3084.194 | 3078.657 | 0.18% |
| getCharC | 2233.422 | 2232.788 | 0.03% |
| getCharL | 6032.213 | 6028.447 | 0.06% |
| getCharLU | 4492.928 | 4482.773 | 0.23% |
| getCharLV | 2220.004 | 2220.231 | -0.01% |
| getIntB | 7996.907 | 8050.658 | -0.67% |
| getIntBU | 9041.783 | 9035.892 | 0.07% |
| getIntBV | 309.469 | 308.076 | 0.45% |
| getIntL | 7887.687 | 7881.362 | 0.08% |
| getIntLU | 8856.416 | 8863.707 | -0.08% |
| getIntLV | 2225.803 | 2225.789 | 0.00% |
| getIntRB | 8619.974 | 8616.985 | 0.03% |
| getIntRBU | 11098.237 | 11100.091 | -0.02% |
| getIntRL | 8959.808 | 8958.688 | 0.01% |
| getIntRLU | 9237.407 | 9236.465 | 0.01% |
| getIntRU | 2502.967 | 2503.585 | -0.02% |
| getIntU | 2492.784 | 2492.675 | 0.00% |
| getLongB | 24807.583 | 24797.555 | 0.04% |
| getLongBU | 14022.093 | 14008.556 | 0.10% |
| getLongBV | 601.878 | 600.904 | 0.16% |
| getLongL | 25076.552 | 25111.661 | -0.14% |
| getLongLU | 14470.997 | 14474.230 | -0.02% |
| getLongLV | 2223.678 | 2223.882 | -0.01% |
| getLongRB | 24769.555 | 24778.684 | -0.04% |
| getLongRBU | 14017.091 | 14024.421 | -0.05% |
| getLongRL | 25070.811 | 25085.936 | -0.06% |
| getLongRLU | 14462.097 | 14467.410 | -0.04% |
| getLongRU | 3056.826 | 3056.270 | 0.02% |
| getLongU | 3045.057 | 3045.650 | -0.02% |
| putBytes4 | 928.032 | 928.111 | -0.01% |
| putBytes4GetBytes | 5876.794 | 5875.995 | 0.01% |
| putBytes4U | 926.596 | 928.596 | -0.22% |
| putBytes4X | 927.929 | 927.928 | 0.00% |
| putChars4B | 5635.803 | 5635.872 | 0.00% |
| putChars4BU | 1142.948 | 1141.809 | 0.10% |
| putChars4BV | 4482.613 | 4480.597 | 0.04% |
| putChars4C | 1132.133 | 1132.881 | -0.07% |
| putChars4L | 5640.644 | 5632.055 | 0.15% |
| putChars4LU | 1141.009 | 1142.132 | -0.10% |
| putChars4LV | 1133.833 | 1133.137 | 0.06% |
| putChars4S | 1132.469 | 1132.250 | 0.02% |
| setCharBS | 6080.539 | 6081.117 | -0.01% |
| setCharBV | 3598.374 | 3591.190 | 0.20% |
| setCharC | 4497.279 | 4544.706 | -1.04% |
| setCharLS | 5615.475 | 5620.162 | -0.08% |
| setCharLV | 2249.104 | 2245.083 | 0.18% |
| setIntB | 7999.139 | 8030.850 | -0.39% |
| setIntBU | 17922.810 | 17942.929 | -0.11% |
| setIntBV | 3237.265 | 3224.414 | 0.40% |
| setIntL | 2124.492 | 2109.906 | 0.69% |
| setIntLU | 4772.256 | 4801.314 | -0.61% |
| setIntLV | 2110.382 | 2120.022 | -0.45% |
| setIntRB | 13773.518 | 13775.889 | -0.02% |
| setIntRBU | 14752.651 | 14754.926 | -0.02% |
| setIntRL | 3226.597 | 3227.019 | -0.01% |
| setIntRLU | 5862.400 | 5882.564 | -0.34% |
| setIntRU | 5915.139 | 5917.139 | -0.03% |
| setIntU | 4794.627 | 4780.927 | 0.29% |
| setLongB | 31661.626 | 31598.635 | 0.20% |
| setLongBU | 25681.380 | 25622.835 | 0.23% |
| setLongBV | 2167.426 | 2164.900 | 0.12% |
| setLongL | 5380.433 | 5321.645 | 1.10% |
| setLongLU | 4281.526 | 4280.263 | 0.03% |
| setLongLV | 2109.982 | 2110.138 | -0.01% |
| setLongRB | 29807.728 | 29826.089 | -0.06% |
| setLongRBU | 24973.926 | 24903.052 | 0.28% |
| setLongRL | 4518.310 | 4518.594 | -0.01% |
| setLongRLU | 4792.258 | 4795.612 | -0.07% |
| setLongRU | 4796.491 | 4792.139 | 0.09% |
| setLongU | 4280.624 | 4507.839 | -5.04% |

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PR Comment: https://git.openjdk.org/jdk/pull/21659#issuecomment-2466029503