in reply to Re^3: Optimizing with Caching vs. Parallelizing (MCE::Map)

in thread Optimizing with Caching vs. Parallelizing (MCE::Map)

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

**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

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

Regards, Mario

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