Groups > comp.lang.java.programmer > #27512

java8 up to 6x slower than java7

Newsgroups	comp.lang.java.programmer
Date	2014-02-15 03:00 -0800
Message-ID	<29a51a94-8f9a-41b1-980f-e8c13e2d11a2@googlegroups.com> (permalink)
Subject	java8 up to 6x slower than java7
From	Dennis Haupt <d.haupt82@gmail.com>

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i wrote a little pathfinder. i can run it under the jdk7 update 51 and it is done in ~20 seconds. under java8, since a long series of builds, a certain part involving deeeeeeeeeep recursion takes ~60 seconds instead of 10.
i suspected the hashmap change of java8 to be the culprit since i perform a lot of put operations, but that's not it - i used the standard  hashmap from scala to be 100% sure the hashmap can't be the reason (or is), and indeed, i get the same performance difference between java7 and 8 with the same hashmap
my profiler (yourkit) shows that java8 spends a much bigger amount of time on garbage collection and allocated more objects. if i take a memory snapshot, can see that the final results are equal, so i have more temporary objects. yourkit also shows that more objects are allocated using java8.
what is up with that?
all i do in the critical method is creating arraylists and performing puts, contains and gets on a hashmap, and the recursive call. the time is, according to yourkit, spend in the method itself, not inside the hashmap or arraylist constructor.
any ideas?

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java8 up to 6x slower than java7 Dennis Haupt <d.haupt82@gmail.com> - 2014-02-15 03:00 -0800
  Re: java8 up to 6x slower than java7 Jan Burse <janburse@fastmail.fm> - 2014-02-15 12:26 +0100
    Re: java8 up to 6x slower than java7 Jan Burse <janburse@fastmail.fm> - 2014-02-15 12:28 +0100
    Re: java8 up to 6x slower than java7 Jan Burse <janburse@fastmail.fm> - 2014-02-15 12:52 +0100
      Re: java8 up to 6x slower than java7 Robert Klemme <shortcutter@googlemail.com> - 2014-02-16 13:10 +0100
        Re: java8 up to 6x slower than java7 Jan Burse <janburse@fastmail.fm> - 2014-02-16 14:38 +0100
          Re: java8 up to 6x slower than java7 Jan Burse <janburse@fastmail.fm> - 2014-02-16 14:43 +0100
            Re: java8 up to 6x slower than java7 Robert Klemme <shortcutter@googlemail.com> - 2014-02-16 14:53 +0100
              Re: java8 up to 6x slower than java7 Jan Burse <janburse@fastmail.fm> - 2014-02-16 20:27 +0100
                Re: java8 up to 6x slower than java7 Jan Burse <janburse@fastmail.fm> - 2014-02-16 20:36 +0100
                Re: java8 up to 6x slower than java7 Robert Klemme <shortcutter@googlemail.com> - 2014-02-17 18:55 +0100
                Re: java8 up to 6x slower than java7 Wanja Gayk <brixomatic@yahoo.com> - 2014-03-02 20:52 +0100
                Re: java8 up to 6x slower than java7 Jan Burse <janburse@fastmail.fm> - 2014-03-03 11:53 +0100
                Re: java8 up to 6x slower than java7 Joerg Meier <joergmmeier@arcor.de> - 2014-03-03 17:16 +0100
                Re: java8 up to 6x slower than java7 Jan Burse <janburse@fastmail.fm> - 2014-03-03 19:53 +0100
                Re: java8 up to 6x slower than java7 Lew <lewbloch@gmail.com> - 2014-03-03 13:44 -0800
      Re: java8 up to 6x slower than java7 Kevin McMurtrie <mcmurtrie@pixelmemory.us> - 2014-02-16 11:24 -0800
  Re: java8 up to 6x slower than java7 Robert Klemme <shortcutter@googlemail.com> - 2014-02-15 12:55 +0100
  Re: java8 up to 6x slower than java7 "Qu0ll" <Qu0llSixFour@gmail.com> - 2014-02-15 23:42 +1100
  Re: java8 up to 6x slower than java7 Roedy Green <see_website@mindprod.com.invalid> - 2014-02-16 00:25 -0800

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