Reimplement Queue to avoid shift/push performance problem#311
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sodabrew merged 1 commit intoeventmachine:masterfrom Nov 2, 2015
Merged
Reimplement Queue to avoid shift/push performance problem#311sodabrew merged 1 commit intoeventmachine:masterfrom
sodabrew merged 1 commit intoeventmachine:masterfrom
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/cc @raggi |
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Hi, this pull request is added into EventMachine-LE: https://github.com/ibc/EventMachine-LE/ |
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It's a little more complex, but that seems par for the course. If the tests all still pass, then 👍 |
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Reimplement Queue to avoid shift/push performance problem
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The existing EM::Queue implementation uses push and shift to shuffle the queued items through an array. Unfortunately, a shift followed by a push has linear time complexity in the size of the array, making queue operations very expensive for long queues.
The patch replaces the @Items array with two separate arrays @sink for pushing elements into it and @drain for shifting out elements. This ensures that both push and shift get amortized constant time complexity.
In addition, the patch introduces a test that demonstrates the performance issues. For me, the new test passes with both Queue implementations, but takes minutes with the old implementation and much less than a second with the new implementation.