RFR: 8317720: RISC-V: Implement Adler32 intrinsic [v2]

[Fei Yang]

On Sat, 6 Apr 2024 02:24:04 GMT, Fei Yang <fyang at openjdk.org> wrote:

>> ArsenyBochkarev has refreshed the contents of this pull request, and previous commits have been removed. Incremental views are not available.
>
> I witnessed performance regression on unmatched board when count > 2048.
> JMH numbers:
> 
> Before:
> Benchmark                      (count)   Mode  Cnt     Score    Error   Units
> TestAdler32.testAdler32Update       64  thrpt   25  1050.761 ± 54.862  ops/ms
> TestAdler32.testAdler32Update      128  thrpt   25   953.858 ± 42.102  ops/ms
> TestAdler32.testAdler32Update      256  thrpt   25   821.011 ± 21.154  ops/ms
> TestAdler32.testAdler32Update      512  thrpt   25   624.207 ± 19.724  ops/ms
> TestAdler32.testAdler32Update     1024  thrpt   25   436.040 ±  5.875  ops/ms
> TestAdler32.testAdler32Update     2048  thrpt   25   265.020 ±  3.058  ops/ms
> TestAdler32.testAdler32Update     5012  thrpt   25   124.934 ±  0.799  ops/ms
> TestAdler32.testAdler32Update     8192  thrpt   25    70.026 ±  0.243  ops/ms
> TestAdler32.testAdler32Update    16384  thrpt   25    35.885 ±  0.055  ops/ms
> TestAdler32.testAdler32Update    32768  thrpt   25    16.883 ±  0.027  ops/ms
> TestAdler32.testAdler32Update    65536  thrpt   25     7.648 ±  0.006  ops/ms
> 
> After:
> Benchmark                      (count)   Mode  Cnt     Score    Error   Units
> TestAdler32.testAdler32Update       64  thrpt   25  4360.280 ± 39.921  ops/ms
> TestAdler32.testAdler32Update      128  thrpt   25  2766.595 ± 16.027  ops/ms
> TestAdler32.testAdler32Update      256  thrpt   25  1634.373 ±  5.412  ops/ms
> TestAdler32.testAdler32Update      512  thrpt   25   880.028 ±  1.463  ops/ms
> TestAdler32.testAdler32Update     1024  thrpt   25   457.724 ±  0.296  ops/ms
> TestAdler32.testAdler32Update     2048  thrpt   25   233.605 ±  0.072  ops/ms
> TestAdler32.testAdler32Update     5012  thrpt   25    96.610 ±  0.020  ops/ms
> TestAdler32.testAdler32Update     8192  thrpt   25    59.275 ±  0.012  ops/ms
> TestAdler32.testAdler32Update    16384  thrpt   25    29.726 ±  0.004  ops/ms
> TestAdler32.testAdler32Update    32768  thrpt   25    14.736 ±  0.009  ops/ms
> TestAdler32.testAdler32Update    65536  thrpt   25     6.658 ±  0.002  ops/ms

> @RealFYang Hi, thanks for pointing out! To achieve additional acceleration, I did a vectorization and re-measured performance on Kendryte K230 with RVV 1.0 enabled:

That's great to hear! I was not aware that it could run a full-featured Linux system.
May I ask what kind of Linux distro are you running with?

> It seems to me that there's a huge room for improvement in the current implementation.

Have you finished improving this with RVV 1.0? I can take another look when that is done.

> BTW, the data I used as a comparison from T-Head board was recorded a few months ago. Is it the code generation that has improved significantly? Or it's just me making some kind of mistake in measurements?

I am not sure what you mean. But I don't think there is a big change in this part?

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PR Comment: https://git.openjdk.org/jdk/pull/18382#issuecomment-2046729405