Hi!

I saw some benchmarks of direct vs. heap buffers - but I can't remember a 
single one where direct buffers were a *big* performance gain. If you're 
copying the buffers just to make it perform better, you'll probably get a huge 
performance penality caused by the copy-logic itself.

Maybe it's possible to remove the copy-logic by using a "duplicate()" of the 
original buffer. This copies only the ByteBuffer-Wrapper, not the underlying 
array.
There is still a tradeoff: Application logic must make sure to not change the 
buffers content anymore! If it does, it gets really ugly.
Shouldn't be a problem for Encoders, but may be if the application reuses the 
buffer (IMHO a bad Idea, anyway)

regards

Steve Ulrich


> Emmanuel Lécharny [mailto:[email protected]] wrote:
>
> Le 1/9/13 11:54 AM, Jeff MAURY a écrit :
> > The problem I see if you choose to copy the user buffer into a
> DirectBuffer
> > is that your memory consumption will double even if the DirectBuffer
> is not
> > allocated on the heap, it may be problematic
> It will double only the time necessary to copy the buffer. Then you can
> discard the HeapBuffer...
>
> All in all, this is currently what happens behind the curtain, as NIO
> copies the HeapBuffer into a HeapBuffer. Doing it on our layer gives us
> some control.
>
> --
> Regards,
> Cordialement,
> Emmanuel Lécharny
> www.iktek.com
>
>



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