PPC64 VSX load/store instructions in stubs

[Michihiro Horie]

Dear Breno, Gustavo, Voker, and Martin,
I am a cowoker of Miki.

I implemented VSX disjoint arraycopy functions for byte, int, and long.
Although Miki had implemented VSX disjoint long arraycopy, we found a
couple of bugs so I fixed it. Would you please review them?

Micro benchmarks for byte and int are as follows. (The one for long is the
same as Miki's, which was attached before by Miki)
(See attached file: ArrayCopyTest_byte.java)(See attached file:
ArrayCopyTest_int.java)

Results are as follows. (For the short result, I used Gustavo's code.)
(See attached file: result_disjoint-arraycopy_vsx-max.jpg)

Patch for Java8:
(See attached file: hotspot_jdk8.diff)

Patch for Java9:
(See attached file: hotspot_jdk9.diff)

Best regards,
--
Michihiro Horie,
IBM Research - Tokyo



From:	Miki M Enoki/Japan/IBM
To:	Breno Leitao <brenohl at br.ibm.com>
Cc:	Gustavo Romero <gromero at linux.vnet.ibm.com>,
            "hotspot-dev at openjdk.java.net" <hotspot-dev at openjdk.java.net>,
            "Doerr, Martin" <martin.doerr at sap.com>,
            "ppc-aix-port-dev at openjdk.java.net"
            <ppc-aix-port-dev at openjdk.java.net>, "Simonis, Volker"
            <volker.simonis at sap.com>, Volker Simonis
            <volker.simonis at gmail.com>
Date:	2016/05/25 00:15
Subject:	Re: PPC64 VSX load/store instructions in stubs


Hi Breno,

Thank you for your reply.

>The same mechanism could be used to copy arrays of short elements, as
Gustavo was
>working on. Do you agree?

I think the mechanism is different with type (byte, short, int, long...).
Gustavo will apply a pach with VSX for short array copy, so it would be
reasonable to use VSX instruction for long array copy, too.

My coworker is also creating byte and int arraycopy with VSX. He will post
an email to this mailing list.
I appreciate it if our patch for byte, int and long copy is applied to
OpenJDK.


Best regards,
Miki






From:	Breno Leitao <brenohl at br.ibm.com>
To:	Miki M Enoki/Japan/IBM at IBMJP, "Doerr, Martin"
            <martin.doerr at sap.com>,
Cc:	Gustavo Romero <gromero at linux.vnet.ibm.com>, Volker Simonis
            <volker.simonis at gmail.com>, "Simonis, Volker"
            <volker.simonis at sap.com>, "ppc-aix-port-dev at openjdk.java.net"
            <ppc-aix-port-dev at openjdk.java.net>,
            "hotspot-dev at openjdk.java.net" <hotspot-dev at openjdk.java.net>
Date:	2016/05/17 02:29
Subject:	Re: PPC64 VSX load/store instructions in stubs



Hi Miki,

On 05/16/2016 02:53 AM, Miki M Enoki wrote:
> I also implemented VSX disjoint long arraycopy.
> I appreciate it if it is applied to OpenJDK, too.

Thanks for the summarized information, this is helpful. Based on your plot,
I
understand we can split the whole scenario in two:

  * Array size smaller than 4k, and then use VSX instructions to perform
copy
  * Array size bigger than 4k, and then use VMX instructions to perform
copy

The same mechanism could be used to copy arrays of short elements, as
Gustavo was
working on. Do you agree?

That said, I understand that a new patch should be generated that
contemplates
both cases on a single patch, ready to be applied on OpenJDK 9 source code.
Hence
a webrev should be generated mapping to bug id
https://bugs.openjdk.java.net/browse/JDK-8154156

If you need any help on the webrev[1] creation and hosting, Gustavo might
help,
since he did this process already.

[1] http://openjdk.java.net/guide/webrevHelp.html

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