RFR: 8266332: Adler32 intrinsic for x86 64-bit platforms [v11]

[John Tortugo]

On Tue, 18 May 2021 00:18:08 GMT, Xubo Zhang <github.com+58006833+xbzhang99 at openjdk.org> wrote:

>> Implement Adler32 intrinsic for x86 64-bit platform using vector instructions.
>> 
>> The benchmark test/micro/org/openjdk/bench/java/util/TestAdler32.java is contributed by Pengfei Li (pli, Pengfei.Li at arm.com).
>> 
>> For this benchmark,  the optimization shows ~5x improvement.
>> 
>> Base:
>> Benchmark (count) Mode Cnt Score Error Units
>> TestAdler32Perf.testAdler32Update 64 avgt 25 0.084 ± 0.001 us/op
>> TestAdler32Perf.testAdler32Update 128 avgt 25 0.104 ± 0.001 us/op
>> TestAdler32Perf.testAdler32Update 256 avgt 25 0.146 ± 0.002 us/op
>> TestAdler32Perf.testAdler32Update 512 avgt 25 0.226 ± 0.002 us/op
>> TestAdler32Perf.testAdler32Update 1024 avgt 25 0.390 ± 0.005 us/op
>> TestAdler32Perf.testAdler32Update 2048 avgt 25 0.714 ± 0.007 us/op
>> TestAdler32Perf.testAdler32Update 4096 avgt 25 1.359 ± 0.014 us/op
>> TestAdler32Perf.testAdler32Update 8192 avgt 25 2.751 ± 0.023 us/op
>> TestAdler32Perf.testAdler32Update 16384 avgt 25 5.494 ± 0.077 us/op
>> TestAdler32Perf.testAdler32Update 32768 avgt 25 11.058 ± 0.160 us/op
>> TestAdler32Perf.testAdler32Update 65536 avgt 25 22.198 ± 0.319 us/op
>> 
>> 
>> With patch:
>> Benchmark (count) Mode Cnt Score Error Units
>> TestAdler32Perf.testAdler32Update 64 avgt 25 0.020 ± 0.001 us/op
>> TestAdler32Perf.testAdler32Update 128 avgt 25 0.025 ± 0.001 us/op
>> TestAdler32Perf.testAdler32Update 256 avgt 25 0.031 ± 0.001 us/op
>> TestAdler32Perf.testAdler32Update 512 avgt 25 0.048 ± 0.001 us/op
>> TestAdler32Perf.testAdler32Update 1024 avgt 25 0.078 ± 0.001 us/op
>> TestAdler32Perf.testAdler32Update 2048 avgt 25 0.139 ± 0.002 us/op
>> TestAdler32Perf.testAdler32Update 4096 avgt 25 0.262 ± 0.004 us/op
>> TestAdler32Perf.testAdler32Update 8192 avgt 25 0.524 ± 0.010 us/op
>> TestAdler32Perf.testAdler32Update 16384 avgt 25 1.017 ± 0.022 us/op
>> TestAdler32Perf.testAdler32Update 32768 avgt 25 2.058 ± 0.052 us/op
>> TestAdler32Perf.testAdler32Update 65536 avgt 25 3.994 ± 0.013 us/op
>
> Xubo Zhang has updated the pull request incrementally with one additional commit since the last revision:
> 
>   remove scratch register from vpmulld

src/hotspot/cpu/x86/assembler_x86.cpp line 7859:

> 7857: void Assembler::vbroadcastf128(XMMRegister dst, Address src, int vector_len) {
> 7858:   assert(VM_Version::supports_avx(), "");
> 7859:   assert(vector_len == AVX_256bit, "");

Looks like "vector_len" can only be AVX_256bit. Do we really need a parameter then?

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PR: https://git.openjdk.java.net/jdk/pull/3806