RFR: 8312425: [vectorapi] AArch64: Optimize vector math operations with SLEEF [v11]

[Andrew Dinn]

On Tue, 9 Jul 2024 12:08:50 GMT, Hamlin Li <mli at openjdk.org> wrote:

>> Hi,
>> Can you help to review the patch?
>> This pr is based on previous work and discussion in [pr 16234](https://github.com/openjdk/jdk/pull/16234), [pr 18294](https://github.com/openjdk/jdk/pull/18294).
>> * NOTE: This pr depends on https://github.com/openjdk/jdk/pull/19185, which includes a README, a script to generate sleef inline headers and generated sleef inline headers.
>> 
>> Compared with previous prs, the major change in this pr is to integrate the source of sleef (for the steps, please check `src/jdk.incubator.vector/linux/native/libvectormath/README`), rather than depends on external sleef things (header or lib) at build or run time.
>> Besides of this change, also modify the previous changes accordingly, e.g. remove some uncessary files or changes especially in make dir of jdk.
>> 
>> Besides of the code changes, one important task is to handle the legal process.
>> 
>> Thanks!
>> 
>> ## Test
>> tests:
>> * test/jdk/jdk/incubator/vector/
>> * test/hotspot/jtreg/compiler/vectorapi/
>> 
>> options:
>> * -XX:UseSVE=1 -XX:+EnableVectorSupport -XX:+UseVectorStubs
>> * -XX:UseSVE=0 -XX:+EnableVectorSupport -XX:+UseVectorStubs
>> * -XX:+EnableVectorSupport -XX:-UseVectorStubs
>> 
>> ## Performance
>> 
>> ### Options
>> * +intrinsic: 'FORK=1;ITER=10;WARMUP_ITER=10;JAVA_OPTIONS=-XX:+UnlockExperimentalVMOptions -XX:+EnableVectorSupport -XX:+UseVectorStubs'
>> * -intrinsic: 'FORK=1;ITER=10;WARMUP_ITER=10;JAVA_OPTIONS=-XX:+UnlockExperimentalVMOptions -XX:+EnableVectorSupport -XX:-UseVectorStubs'
>> 
>> ### Float
>> data
>> <google-sheets-html-origin style="caret-color: rgb(0, 0, 0); color: rgb(0, 0, 0); font-style: normal; font-variant-caps: normal; font-weight: 400; letter-spacing: normal; orphans: auto; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; widows: auto; word-spacing: 0px; -webkit-text-stroke-width: 0px; text-decoration: none;">
>> Benchmark | (size) | Mode | Cnt | Error | Units | Score +intrinsic (UseSVE=1) | Score -intrinsic | Improvement(UseSVE=1) | Score +intrinsic (UseSVE=0) | Score -intrinsic | Improvement (UseSVE=0)
>> -- | -- | -- | -- | -- | -- | -- | -- | -- | -- | -- | --
>> Float128Vector.ACOS | 1024 | thrpt | 10 | 0.015 | ops/ms | 245.439 | 101.483 | 2.419 | 245.733 | 102.033 | 2.408
>> Float128Vector.ASIN | 1024 | thrpt | 10 | 0.013 | ops/ms | 296.702 | 103.559 | 2.865 | 296.741 | 103.18 | 2.876
>> Float128Vector.ATAN | 1024 | thrpt | 10 | 0.004 | ops/ms | 196.862 | 49.627 | 3.967 | 195.891 | 49.771 | 3.936
>> Float128Vector.ATAN...
>
> Hamlin Li has updated the pull request incrementally with one additional commit since the last revision:
> 
>   skip TANH

Obviously we need to include pre-generated sources in the repo so that most people can just build the library using *sanctioned* code without needing to regenerate anything.

I absolutely agree with @theRealAph that we need to have all relevant SLEEF header build scripts in the OpenJDK repo so that anyone who want to rebuild the headers can do so. I don't believe it is just packagers who will want to do that and it is good open source practice to allow and, where possible, make it easy for anyone to do so.

Given the size of the original SLEEF sources I also agree with @theRealAph it is no great burden to include them in the jdk repo. However, I am not averse to @vidmik's alternative of putting the sources in an openjdk/sleef repo. That would be fine so long as the openjdk repo includes SLEEF build scripts that pull a determinate hash to generate the headers.

Likewise I agree with @vidmik's suggestion of omitting the extra packages the SLEEF generate step requires from the standard configure/make scripts would be fine so long as the SLEEF build scripts prompt users on what to install. We don't want to force everyone to install packages that they don't need. But we do still need to make it straightforward for those who do want to regenerate the sources to achieve that goal.

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

PR Comment: https://git.openjdk.org/jdk/pull/18605#issuecomment-2230559757