On Feb 13, 9:06 am, Vincent Foley <vfo...@gmail.com> wrote:
> Should I add this to the list of issues in the Google Code tracker?
>
No. Those hints were suspect to begin with.
.get returns a byte already, and .getShort a short, so those hints
shouldn't do anything useful.
Similarly, coercing to primitive on return doesn't help much as the
result is always boxed.
The code should have been:
(defn get-byte [#^ByteBuffer buf]
(let [x (int (.get buf))]
(bit-and x 0xff)))
(defn get-short [#^ByteBuffer buf]
(let [x (int (.getShort buf))]
(bit-and x 0xffff))))
but there weren't inline conversions from byte/short/char to int. I've
added them in SVN 1279.
get-byte
"Elapsed time: 13.051 msecs"
get-short
"Elapsed time: 10.747 msecs"
Thanks for the report.
Rich
>
> On Feb 12, 4:15 pm, Vincent Foley <vfo...@gmail.com> wrote:
>
> > Hello,
>
> > I was surprised today to see that my Starcraft replay program became
> > slower when I updated my Clojure working copy. About a week ago,
> > Chouser helped me adding type hints to avoid reflection in my
> > functions. The warnings came back today.
>
> > I started going through the different revisions of Clojure starting at
> > r1260 and I found that the warnings (and slowness) appear starting at
> > r1265:
>
> > ------------------------------------------------------------------------
> > r1265 | richhickey | 2009-02-10 12:24:20 -0500 (Tue, 10 Feb 2009) | 1
> > line
> > Changed paths:
> > M /trunk/src/clj/clojure/core.clj
>
> > added inlining on remaining coercions
> > ------------------------------------------------------------------------
>
> > I have created a small demo program with my functions to show the
> > difference. Here is the program and the output with r1264 and r1265.
>
> > (set! *warn-on-reflection* true)
>
> > (ns slowdemo
> > (:import [java.nio ByteBuffer]))
>
> > (defn get-byte
> > [#^ByteBuffer buf]
> > (let [x (byte (.get buf))]
> > (short (bit-and x 0xff))))
>
> > (defn get-short
> > [#^ByteBuffer buf]
> > (let [x (short (.getShort buf))]
> > (int (bit-and x 0xffff))))
>
> > (defn buf []
> > (ByteBuffer/wrap (into-array Byte/TYPE (map byte (range 256)))))
>
> > (println "get-byte")
> > (time
> > (dotimes [i 100]
> > (let [b (buf)]
> > (dotimes [j 256]
> > (get-byte b)))))
>
> > (println "get-short")
> > (time
> > (dotimes [i 100]
> > (let [b (buf)]
> > (dotimes [j 128]
> > (get-short b)))))
>
> > $ time java -server -cp $HOME/src/clojure-old/clojure.jar:.
> > clojure.main slowdemo.clj
> > get-byte
> > "Elapsed time: 308.339245 msecs"
> > get-short
> > "Elapsed time: 188.635614 msecs"
> > real: 3.946s; user: 2.720s; sys: 1.064s; CPU: 95.89%
>
> > $ time java -server -cp $HOME/src/clojure-old/clojure.jar:.
> > clojure.main slowdemo.clj
> > Reflection warning, line: 9 - call to and can't be resolved.
> > Reflection warning, line: 14 - call to and can't be resolved.
> > get-byte
> > "Elapsed time: 2765.621864 msecs"
> > get-short
> > "Elapsed time: 1134.288161 msecs"
> > real: 7.400s; user: 4.928s; sys: 2.196s; CPU: 96.27%
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