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Re: Forth vs Java in calculating partial sum ;)

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On Tue, 15 Apr 2014 09:00:43 -0700
Paul Rubin <no.email@nospam.invalid> wrote:

> anton@mips.complang.tuwien.ac.at (Anton Ertl) writes:
> > Does not look like my memory-bound idea is actually true, and I
> > don't know how to explain the variations (especially why Paysan is
> > slower with a big array, but faster with a small one).
> 
> I've been wondering about this too-- one idea is that the serial
> bandwidth of modern DRAM is tremendous, and maybe there is some cache
> preloading happening in the cpu, so big and small arrays don't end up
> that much different.  With random access the big array might be
> much slower.  

Exactly right. I have tested qsort on doubly linked list
and accessing nodes serially is faster than randomly.
Also in place sort (assigning values) instead of relinking nodes
results in much faster linked list eg traversing.
So if nodes are serially placed in memory it is much
faster than if nodes are randomly placed in memory.
Speed up was significant even with just 512kb of cache
on P4.

-- 
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Forth vs Java in calculating partial sum ;) Melzzzzz <mel@zzzzz.com> - 2014-04-12 19:11 +0200
  Re: Forth vs Java in calculating partial sum ;) Paul Rubin <no.email@nospam.invalid> - 2014-04-12 10:15 -0700
    Re: Forth vs Java in calculating partial sum ;) Melzzzzz <mel@zzzzz.com> - 2014-04-14 22:15 +0200
      Re: Forth vs Java in calculating partial sum ;) stephenXXX@mpeforth.com (Stephen Pelc) - 2014-04-14 23:20 +0000
        Re: Forth vs Java in calculating partial sum ;) Melzzzzz <mel@zzzzz.invalid> - 2014-04-15 04:18 +0200
          Re: Forth vs Java in calculating partial sum ;) m.a.m.hendrix@tue.nl - 2014-04-15 00:32 -0700
            Re: Forth vs Java in calculating partial sum ;) stephenXXX@mpeforth.com (Stephen Pelc) - 2014-04-15 11:33 +0000
            Re: Forth vs Java in calculating partial sum ;) Melzzzzz <mel@zzzzz.com> - 2014-04-15 15:55 +0200
          Re: Forth vs Java in calculating partial sum ;) anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2014-04-15 14:44 +0000
            Re: Forth vs Java in calculating partial sum ;) Paul Rubin <no.email@nospam.invalid> - 2014-04-15 09:00 -0700
              Re: Forth vs Java in calculating partial sum ;) Melzzzzz <mel@zzzzz.invalid> - 2014-04-15 19:38 +0200
            Re: Forth vs Java in calculating partial sum ;) mhx@iae.nl - 2014-04-15 11:41 -0700
            Re: Forth vs Java in calculating partial sum ;) Melzzzzz <mel@zzzzz.com> - 2014-04-16 07:10 +0200
            Re: Forth vs Java in calculating partial sum ;) Melzzzzz <mel@zzzzz.com> - 2014-04-16 07:24 +0200
              Re: Forth vs Java in calculating partial sum ;) anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2014-04-16 10:24 +0000
  Re: Forth vs Java in calculating partial sum ;) mhx@iae.nl - 2014-04-12 13:01 -0700
    Re: Forth vs Java in calculating partial sum ;) mhx@iae.nl - 2014-04-12 13:06 -0700
    Re: Forth vs Java in calculating partial sum ;) Paul Rubin <no.email@nospam.invalid> - 2014-04-12 15:49 -0700
      Re: Forth vs Java in calculating partial sum ;) mhx@iae.nl - 2014-04-12 23:00 -0700
        Re: Forth vs Java in calculating partial sum ;) Paul Rubin <no.email@nospam.invalid> - 2014-04-13 00:14 -0700
          Re: Forth vs Java in calculating partial sum ;) mhx@iae.nl - 2014-04-13 02:03 -0700
        Re: Forth vs Java in calculating partial sum ;) Bernd Paysan <bernd.paysan@gmx.de> - 2014-04-13 14:52 +0200
    Re: Forth vs Java in calculating partial sum ;) "WJ" <w_a_x_man@yahoo.com> - 2014-12-12 23:45 +0000
  Re: Forth vs Java in calculating partial sum ;) mhx@iae.nl - 2014-04-12 13:33 -0700
    Re: Forth vs Java in calculating partial sum ;) Bernd Paysan <bernd.paysan@gmx.de> - 2014-04-12 22:50 +0200
      Re: Forth vs Java in calculating partial sum ;) Melzzzzz <mel@zzzzz.invalid> - 2014-04-13 03:30 +0200
      Re: Forth vs Java in calculating partial sum ;) anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2014-04-13 13:43 +0000
  Re: Forth vs Java in calculating partial sum ;) Andrew Haley <andrew29@littlepinkcloud.invalid> - 2014-04-15 10:05 -0500
  Re: Forth vs Java in calculating partial sum ;) "WJ" <w_a_x_man@yahoo.com> - 2014-12-05 05:46 +0000
  Re: Forth vs Java in calculating partial sum ;) "WJ" <w_a_x_man@yahoo.com> - 2014-12-10 09:50 +0000
    Re: Forth vs Java in calculating partial sum ;) "WJ" <w_a_x_man@yahoo.com> - 2014-12-10 18:29 +0000

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