RFR 8078563 - add profitability tests for reductions

[Vladimir Kozlov]

I want to test it with my and your tests when I have time.

Thanks,
Vladimir

On 4/29/15 2:38 PM, Berg, Michael C wrote:
> Vladimir, does this patch also look ok to you as well?
>
> I believe you have reviewed the changes.
>
> Thanks,
>
> Michael
>
> *From:*Christian Thalinger [mailto:christian.thalinger at oracle.com]
> *Sent:* Wednesday, April 29, 2015 10:27 AM
> *To:* Berg, Michael C
> *Cc:* hotspot-compiler-dev at openjdk.java.net
> *Subject:* Re: RFR 8078563 - add profitability tests for reductions
>
> I think this looks good but as I said I’m not an expert in this area.
>   It would be good to have an additional reviewer.
>
>     On Apr 29, 2015, at 10:23 AM, Berg, Michael C
>     <michael.c.berg at intel.com <mailto:michael.c.berg at intel.com>> wrote:
>
>     Christian, do you have any additional comments or does the code look ok?
>
>     Thanks,
>
>     Michael
>
>     *From:*Christian Thalinger [mailto:christian.thalinger at oracle.com]
>     *Sent:* Monday, April 27, 2015 9:49 AM
>     *To:* Berg, Michael C
>     *Cc:* hotspot-compiler-dev at openjdk.java.net
>     <mailto:hotspot-compiler-dev at openjdk.java.net>
>     *Subject:* Re: RFR 8078563 - add profitability tests for reductions
>
>     *+       // Length 2 reductions of INT/LONG do not offer performance benefits*
>
>     *+       if (((arith_type->basic_type() == T_INT) || (arith_type->basic_type() == T_LONG)) && (size == 2)) {*
>
>     I don’t know that code very well but can there be reductions with
>     size == 1?
>
>         On Apr 23, 2015, at 5:53 PM, Berg, Michael C
>         <michael.c.berg at intel.com <mailto:michael.c.berg at intel.com>> wrote:
>
>         Hi Folks,
>
>         We (Intel) would like to add profitability tests to superword to
>         gate scenarios where reduction optimization overhead is roughly
>         equal to the benefit gained by vectorization.
>
>         We would like to do this for all x86 enabled microarchitectures
>         that support reductions and superword.  This new constraint was
>         tested on SSE and AVX (1,2) enabled platforms.
>         The contribution as referenced by RFR 8078563 is defined by the
>         information at the links below.
>
>         Please review this bug entry and its code and comment as needed:
>
>         https://bugs.openjdk.java.net/browse/JDK-8078563
>
>         And its code and test addition (this is a small patch):
>
>         http://cr.openjdk.java.net/~kvn/8078563/webrev/
>
>
>
>         Vladimir Koslov has offered to sponsor this patch.
>
>         Thanks,
>
>         Michael
>