ByteBuffer performance issue in Java 9? (original) (raw)

Michael McCandless lucene at mikemccandless.com
Mon Mar 13 14:16:47 UTC 2017

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

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