RFR: 8323116: [REDO] Computational test more than 2x slower when AVX instructions are used

Tue Mar 26 23:47:38 UTC 2024

The goal of this PR is improve the performance of convert instructions and address the slowdown when AVX=0 is used.

The performance data using the ComputePI.java benchmark (part of this PR) is as follows:
<html xmlns:o="urn:schemas-microsoft-com:office:office"
xmlns:dt="uuid:C2F41010-65B3-11d1-A29F-00AA00C14882"
xmlns="http://www.w3.org/TR/REC-html40">

<head>

<meta name=ProgId content=OneNote.File>
<meta name=Generator content="Microsoft OneNote 15">
</head>

<body lang=en-US style='font-family:Calibri;font-size:11.0pt'>

<div style='direction:ltr'>

Benchmark (ns/op) | Stock JDK | This PR (AVX=3) | Speedup
-- | -- | -- | --
ComputePI.compute_pi_dbl_flt | 511.34 | 511.226 | 1.0
ComputePI.compute_pi_flt_dbl | 2024.06 | 541.544 | 3.7
ComputePI.compute_pi_int_dbl | 695.482 | 506.546 | 1.4
ComputePI.compute_pi_int_flt | 799.268 | 450.298 | 1.8
ComputePI.compute_pi_long_dbl | 802.992 | 577.984 | 1.4
ComputePI.compute_pi_long_flt | 628.62 | 549.057 | 1.1

</div>

</body>

</html>

<html xmlns:o="urn:schemas-microsoft-com:office:office"
xmlns:dt="uuid:C2F41010-65B3-11d1-A29F-00AA00C14882"
xmlns="http://www.w3.org/TR/REC-html40">

<head>

<meta name=ProgId content=OneNote.File>
<meta name=Generator content="Microsoft OneNote 15">
</head>

<body lang=en-US style='font-family:Calibri;font-size:11.0pt'>

<div style='direction:ltr'>

Benchmark (ns/op) | Stock JDK | This PR (AVX=0) | Speedup
-- | -- | -- | --
ComputePI.compute_pi_dbl_flt | 473.778 | 472.529 | 1.0
ComputePI.compute_pi_flt_dbl | 536.004 | 538.418 | 1.0
ComputePI.compute_pi_int_dbl | 458.08 | 460.245 | 1.0
ComputePI.compute_pi_int_flt | 477.305 | 476.975 | 1.0
ComputePI.compute_pi_long_dbl | 455.132 | 455.064 | 1.0
ComputePI.compute_pi_long_flt | 474.734 | 476.571 | 1.0

</div>

</body>

</html>

-------------

Commit messages:
 - fix whitespace changes
 - 8323116: [REDO] Computational test more than 2x slower when AVX instructions are used

Changes: https://git.openjdk.org/jdk/pull/18503/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=18503&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8323116
  Stats: 211 lines in 4 files changed: 205 ins; 0 del; 6 mod
  Patch: https://git.openjdk.org/jdk/pull/18503.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/18503/head:pull/18503

PR: https://git.openjdk.org/jdk/pull/18503