System.arraycopy

[Tom Rodriguez]

On Jun 5, 2014, at 2:39 PM, Deneau, Tom <tom.deneau at amd.com> wrote:

> Christian --
> 
> For now just going for functionally correct, will address performance issues in the future.  But yes there are vector instructions that could help even in a single workitem.
> 
> Is there already a pure java implementation of System.arrayCopy we could substitute?

UnsafeArrayCopyNode is pretty much that.  The flag CallArrayCopy controls whether it prefers the hotspot stubs for array copy or not but it should be able to fall back to UnsafeArrayCopyNode.

tom

> 
> I guess we would want to use the logic to do different substitutions based on the type of the array (like in ArrayCopySnippets)?  
> 
> any other advice for implementing this?
> 
> -- Tom
> 
> 
> 
>> -----Original Message-----
>> From: Christian Thalinger [mailto:christian.thalinger at oracle.com]
>> Sent: Thursday, June 05, 2014 3:45 PM
>> To: Deneau, Tom
>> Cc: graal-dev at openjdk.java.net
>> Subject: Re: System.arraycopy
>> 
>> Well, I guess the easiest but maybe not most performant way would be to
>> have a substitution and implement it in plain Java.
>> 
>> On the other hand you could rely on vectorization and the power of GPUs
>> to produce good, parallel code :-)
>> 
>> On Jun 5, 2014, at 1:29 PM, Deneau, Tom <tom.deneau at amd.com> wrote:
>> 
>>> Since we cannot handle "foreign calls" in the hsail backend, what is
>> the preferred way to implement System.arraycopy?  Right now, we are
>> deferring to the host and so getting an ArrayCopyCallNode which gets
>> lowered to a graph containing a ForeignCallNode.
>>> 
>>> I confess to being a little confused with the ArrayCopyNode and
>> Snippets, UnsafeArrayCopyNode and Snippets, ArrayCopyCallNode, etc.
>>> 
>>> -- Tom
>>> 
>