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Posted to dev@systemds.apache.org by "JulianJuelg (via GitHub)" <gi...@apache.org> on 2026/01/30 22:57:46 UTC

[PR] Vector API Implementation for dense codegen primitives (Divisions, Aggregations, Comparisons, MultiplyAdd) + benchmarks [systemds]

JulianJuelg opened a new pull request, #2428:
URL: https://github.com/apache/systemds/pull/2428

   This PR adds a Java Vector API implementation for dense codegen primitives in the following groups:
   
   - Aggregation
   - Division
   - Comparison
   - Multiply-add (remaining)
   
   The new vectorized implementations were benchmarked against the previous scalar-loop versions (see results below) with JMH microbenchmarks and a standalone Java benchmark suite included in this PR. In most cases, both harnesses show the same trend. In caseswhere they differ slightly, JMH is used as the primary signal due to lower volatility.
   
   For each primitive, I compared the Vector API version to the existing scalar loop:
   - If performance was equal, or better, I replaced the scalar loop with the vectorized implementation.
   - If the Vector API version was slower, I kept the scalar implementation as the default and left the vectorized version in the codebase for reference
   
   Benchmark setup
   JDK version : 21
   JMH version: 1.37
   OS: macOS
   Machine: (Apple M2/M, 16 GB RAM, 128-bit vector width/ SIMD)
   Input size (double arrays): 1,000,000 elements
   Warmup time: 1s per primitive
   Measurement: 1 Iteration
   JMH params: 2 Forks
   
   Note: These benchmarks were run with a 128-bit SIMD vector width, which is only 2 lanes for doubles. On production deployments with wider SIMD (e.g., 256-bit or 512-bit where available), the vectorized implementations are expected to provide equal or better speedups due to increased lane-level parallelism.
   
   
   | Primitive Function | ns/op (JMH) | JMH Test: Speedup with Vector API | Java Test: Speedup with Vector API | Replaced |
   |---|---:|---:|---:|---|
   | vectDivAdd | 231671 | 1.066 | 1.887 |Yes |
   | vectDivAdd2 | 218818 | 1.066 | 1.686 | Yes|
   | vectDivWrite | 359339 | 0.687 | 1.489 | No |
   | vectDivWrite2 | 343183 | 0.7215 | 0.717 | No |
   | vectDivWrite3 | 535898 | 0.7821 | 0.603 | No |
   | rowMaxsVectMult | 298328 | 1.006 | 1.346 | Yes |
   | rowMaxsVectMult_aix | 738767 | 0.115 | 0.077 | No |
   | vectSum | 142065 | 0.322 | 0.565 | No |
   | vectMax | 596046 | 2.002 | 1.933 |Yes |
   | vectCountnnz | 297805 | 1.594 | 1.538 | Yes|
   | vectEqualAdd | 427437 | 1.959 | 2.077 | Yes |
   | vectEqualWrite2 | 414717 | 1.183 | 0.801 | Yes |
   | vectEqualWrite | 415329 | 1.189 | 1.402 | Yes |
   | vectGreaterAdd | 427981 | 1.936 | 2.114 | Yes |
   | vectGreaterWrite2 | 552023 | 0.588 | 0.919 | No |
   | vectGreaterWrite | 458332 | 1.309 | 0.927 | Yes |
   | vectLessAdd | 531844 | 2.433 | 2.052 | Yes |
   | vectLessWrite2 | 545457 | 1.011 | 0.951 | Yes |
   | vectLessWrite | 414025 | 1.203 | 1.039 | Yes |
   | vectLessequalAdd | 426307 | 1.960 | 2.052 | Yes |
   | vectLessequalWrite2 | 540476 | 1.014 | 0.962 | Yes |
   | vectLessequalWrite | 414514 | 1.181 | 0.953 | Yes |
   | vectMin | 589668 | 2.000 | 1.996 | Yes |
   | vectMult2Add | 228636 | 1.052 | 1.284 | Yes |
   | vectMult2Write | 377074 | 2.136 | 1.375 |Yes  |
   | vectNotequalAdd | 424749 | 1.945 | 1.643 | Yes |
   | vectNotequalWrite2 | 566433 | 0.714 | 0.821 | No |
   | vectNotequalWrite | 417206 | 1.203 | 0.941 | Yes |
   


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Re: [PR] [SYSTEMDS-3920] Vector API Implementation for dense codegen primitives (Divisions, Aggregations, Comparisons, MultiplyAdd) + benchmarks [systemds]

Posted by "mboehm7 (via GitHub)" <gi...@apache.org>.
mboehm7 closed pull request #2428: [SYSTEMDS-3920] Vector API Implementation for dense codegen primitives (Divisions, Aggregations, Comparisons, MultiplyAdd) + benchmarks
URL: https://github.com/apache/systemds/pull/2428


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Re: [PR] [SYSTEMDS-3920] Vector API Implementation for dense codegen primitives (Divisions, Aggregations, Comparisons, MultiplyAdd) + benchmarks [systemds]

Posted by "mboehm7 (via GitHub)" <gi...@apache.org>.
mboehm7 commented on PR #2428:
URL: https://github.com/apache/systemds/pull/2428#issuecomment-4148211778

   Thanks for this great contribution @JulianJuelg. During the merge, I fixed the remaining warnings, formatting issues, and missing licenses.


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