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Hi rjt and fellow Monks,

I updated the parallel demonstrations here and here to ensure orderly output plus cache miss update for parallel iM71. Then captured results for 1e8. Note that running parallel involves File::Map, pack, and unpack. Running Inline::C involves compiling C code on the first run.

Testing was done on a Windows 10 host inside a Docker container running Ubuntu 18.04.x and Perl 5.30.1. The hardware is an AMD 3970x box (32-cores with SMT disabled).

1e8 Output:

Collatz(63728127) has sequence length of 950 steps
Collatz(95592191) has sequence length of 948 steps
Collatz(96883183) has sequence length of 811 steps
Collatz(86010015) has sequence length of 798 steps
Collatz(98110761) has sequence length of 749 steps
Collatz(73583070) has sequence length of 746 steps
Collatz(73583071) has sequence length of 746 steps
Collatz(36791535) has sequence length of 745 steps
Collatz(55187303) has sequence length of 743 steps
Collatz(56924955) has sequence length of 743 steps
Collatz(82780955) has sequence length of 741 steps
Collatz(85387433) has sequence length of 741 steps
Collatz(63101607) has sequence length of 738 steps
Collatz(64040575) has sequence length of 738 steps
Collatz(93128574) has sequence length of 736 steps
Collatz(93128575) has sequence length of 736 steps
Collatz(94652411) has sequence length of 736 steps
Collatz(96060863) has sequence length of 736 steps
Collatz(46564287) has sequence length of 735 steps
Collatz(69846431) has sequence length of 733 steps
[download]

Performance:

1e8: parallel, 32 cores (File::Map, pack, unpack):
  https://www.perlmonks.org/?node_id=11115544
  https://www.perlmonks.org/?node_id=11115780

     Laurent + updates    3.474s
        iM71 + updates    2.701s
    Step counting in C    1.654s

1e8: parallel, 16 cores

     Laurent + updates    6.219s
        iM71 + updates    4.787s
    Step counting in C    2.793s

1e8: parallel,  8 cores

     Laurent + updates   12.061s
        iM71 + updates    9.200s
    Step counting in C    5.258s

1e8: parallel,  4 cores

     Laurent + updates   23.615s
        iM71 + updates   17.935s
    Step counting in C   10.056s

1e8: parallel,  2 cores

     Laurent + updates   46.146s
        iM71 + updates   34.342s
    Step counting in C   19.084s

1e8: non-parallel (Array):
  https://www.perlmonks.org/?node_id=11115841

     Laurent + updates   53.961s
        iM71 + updates   48.673s
    Step counting in C   19.023s
[download]

Parallel now matches serial for sequences with equal number of steps (i.e. smallest sequence first).

Regards, Mario

In reply to Re^4: Optimizing with Caching vs. Parallelizing (MCE::Map) by marioroy
in thread Optimizing with Caching vs. Parallelizing (MCE::Map) by 1nickt

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