[aarch64-port-dev ] [10] RFR: 8187472 - AARCH64: array_equals intrinsic doesn't use prefetch for large arrays

[Ningsheng Jian]

Hi Dmitrij,

I can see regressions on some hardware with your patch.

Could you please try the micro-benchmark below on your systems?

http://people.linaro.org/~ningsheng.jian/test/StringOps.java

$ java -jar ./target/benchmarks.jar "StringEqualsLarge" -wi 10 -f 3 -i 10

Seems that your patch affects the inlining.

Thanks,
Ningsheng

On 10 November 2017 at 22:52, Dmitrij Pochepko
<dmitrij.pochepko at bell-sw.com> wrote:
>
>
> On 10.11.2017 17:28, Andrew Haley wrote:
>>
>> On 10/11/17 14:19, Dmitrij Pochepko wrote:
>>
>>> please take a look at merged simd/non-simd version.
>>
>> +    if (UseSIMDForArrayEquals) {
>> +      __ ld1(v0, v1, v2, v3, __ T2D, Address(__ post(a1, 64)));
>> +      __ ld1(v4, v5, v6, v7, __ T2D, Address(__ post(a2, 64)));
>>
>> Is this post-increment correct?  It should be a multiple of wordSize.
>
> It's correct, since we're loading 4x128-bit registers, which is 64 bytes.
> But I've changed it to "4 * 2 * wordSize", which has the same value.
>>
>>
>> Also, the indentation in generate_large_array_equals is wrong.
>>
> Thank you for noticing it.
>
> Please take a look at
> http://cr.openjdk.java.net/~dpochepk/8187472/webrev.03/
>
>
> Thanks,
> Dmitrij