Webrev for first version of HSA offload integer reduce

[Eric Caspole]

On 06/09/2014 01:07 PM, Christian Thalinger wrote:
>
> On Jun 9, 2014, at 9:40 AM, Caspole, Eric <Eric.Caspole at amd.com
> <mailto:Eric.Caspole at amd.com>> wrote:
>
>> Hi everybody,
>> I put up a new webrev that allows some IntStream.reduce() to be
>> offloaded to HSA:
>>
>> http://cr.openjdk.java.net/~ecaspole/graal_int_reduce1/webrev/
>
>
>     src/gpu/hsail/vm/hsailKernelArguments.hpp
>
> +  virtual void collectArgs() {
>
> Does this really have to be in the .hpp file?  I see that the base class
> has it in the .hpp file too.

No it doesn't have to be there, it is just some historical thing I don't 
know why. I can change that.

>
>>
>> This works with a Sumatra webrev I will eventually add into the
>> Sumatra JDK repo:
>>
>> http://cr.openjdk.java.net/~ecaspole/sumatra_int_reduce_1/webrev/
>>
>> This combo allows offloading IntStream.parallel().reduce() for
>> Integer::sum, Integer::max, and Integer::min. It builds a kernel from
>> a hand made HSAIL string of code that gets called from the new Stream
>> API diversion code in the Sumatra part.
>>
>> Eventually we hope to have regular compilation of user reduce
>> functions but this allows us to do experiments with workloads before
>> we get all the details of reduce compilation in place such as barrier
>> placement and group size nuances.
>
> Presumably that will remove the hand-made code eventually?

Yes. I just want to be able to expose this interesting functionality in 
the mean time.

>
>>
>> In the current Kaveri hardware version of Okra, it uses group size 256
>> by default and this reduce code is designed to work only with 256.
>> Also, because it is a handmade kernel, it only runs with
>> -UseHSAILDeoptimization and -UseCompressedOops.
>> In the included reduce tests, they will skip if the correct flags are
>> not there for the tests to run correctly.
>>
>> This webrev also changes the way the kernel args are processed to look
>> at the actual args type rather than by the type signature of the
>> kernel method.
>> Regards,
>> Eric
>>
>