think.byte-buffer

Experiment to see what best performance is possible when marshalling between types.

Turns out that for large buffers you can beat the best possible on the jvm by a factor of 4 or 5 which sounds like a lot but you really need large buffers and for this to be noticeable your entire system would have to be gated on transferring between buffers of primitive datatypes.

In any case, here are the test results on my computer:

chrisn@chrisn-dt:~/dev/think.byte-buffer$ lein test

lein test think.byte-buffer-test
typed-buffer-marshal-test
"Elapsed time: 6.506655 msecs"
typed-buffer-reverse-marshal-test
"Elapsed time: 6.522338 msecs"
nio-buffer-marshal-test
"Elapsed time: 41.431342 msecs"
javacpp marshal test
"Elapsed time: 39.997473 msecs"
typed-buffer-same-type-time-test
"Elapsed time: 6.706792 msecs"
new-buffer-same-type-time-test
"Elapsed time: 4.252181 msecs"
float array -> double array fast path
"Elapsed time: 20.762307 msecs"
float array -> double array view fast path
"Elapsed time: 20.833246 msecs"

Ran 1 tests containing 0 assertions.
0 failures, 0 errors.
chrisn@chrisn-dt:~/dev/think.byte-buffer$ 

think.byte-buffer> (def mgr (create-manager))
#'think.byte-buffer/mgr
think.byte-buffer> (def test-data (._allocate mgr (* 20 Double/BYTES) "doubles" 15))
#'think.byte-buffer/test-data
think.byte-buffer> (def src-ary (double-array (range 20)))
#'think.byte-buffer/src-ary
think.byte-buffer> (.copy mgr src-ary 0 test-data 0 10)
nil
think.byte-buffer> (def dst (double-array (range 10)))
#'think.byte-buffer/dst
think.byte-buffer> (def dst (double-array 10)))
#'think.byte-buffer/dst
RuntimeException Unmatched delimiter: )  clojure.lang.Util.runtimeException (Util.java:221)
think.byte-buffer> (def dst (double-array 10))
#'think.byte-buffer/dst
think.byte-buffer> (.copy mgr src-ary 0 dst 0 10)
IllegalArgumentException No matching method found: copy for class think.byte_buffer.ByteBuffer$BufferManager  clojure.lang.Reflector.invokeMatchingMethod (Reflector.java:80)
think.byte-buffer> (.copy mgr test-data 0 dst 0 10)
nil
think.byte-buffer> dst
#<[D@5ea099a>
think.byte-buffer> (vec dst)
[0.0 1.0 2.0 3.0 4.0 5.0 6.0 7.0 8.0 9.0]
think.byte-buffer> (def dst (short-array 10))
#'think.byte-buffer/dst
think.byte-buffer> (.copy mgr test-data 0 dst 0 10)
nil
think.byte-buffer> (vec dst)
[0 1 2 3 4 5 6 7 8 9]
think.byte-buffer> (def dst (float-array 10))
#'think.byte-buffer/dst
think.byte-buffer> (vec dst)
[0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0]
think.byte-buffer> (.copy mgr test-data 0 dst 0 10)
nil
think.byte-buffer> (vec dst)
[0.0 1.0 2.0 3.0 4.0 5.0 6.0 7.0 8.0 9.0]
think.byte-buffer>

License

Copyright © 2016 FIXME

Distributed under the Eclipse Public License either version 1.0 or (at your option) any later version.