ByteBuffer performance issue in Java 9?

[Michael McCandless]

Hi Uwe,

OK, I'll test with NIOFSDirectory as well ... that's a good idea.

I do remember testing earlier Java 9 builds long ago, but I can't remember
what the outcome was.

Mike McCandless

http://blog.mikemccandless.com

On Mon, Mar 13, 2017 at 6:35 AM, Uwe Schindler <uschindler at apache.org>
wrote:

> Hi Andrew,
>
> yes that was my impression, too.
>
> Just for cross-checking: Mike, is it possible to also add a perf
> comparison between Java 8 and Java 9 when using SimpleFSDirectory or
> NIOFSDirectory (which are both FileChannel based since Java 7, the name is
> just backwards-compatibility)? If we see a slowdown there (maybe even
> larger) than it is not related to ByteBuffer positional/byte-wise reads and
> there is a general performance issue somewhere else.
>
> > Right, but ByteBuffers were significantly rewritten for a significant
> > performance *increase*.  Any slowdown shows that something has gone
> > very wrong indeed.
>
> That would be a pity, because of that we should check the above case with
> non-mmap based, conventional index access. As far as I remember: at the
> time when you announced the bytebuffer improvements we did some performance
> measurements and were impressed by the speedup. I think Robert Muir did
> something. Mike, do you know?
>
> Maybe we should check with a Java 9 preview build from that time. I know
> that you can download older builds by changing the build number in the
> download URL.
>
> Uwe
>
>