Avoid quadratic memory blowup in TermDag::to_string #496
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RiscInside
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CodSpeed Performance ReportMerging #496 will not alter performanceComparing Summary
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For reference, the generated string is 889MB! We don't want to compute it if user didn't ask for it. |
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Zulip
Current version of
TermDag::to_stringcaches a string for each DAG node. This results in quadratic memory blowup (these strings contain each other) which prevents vector benchmark from running on my machine.This PR fixes the issue by building one result string and using string ranges to refer to already built substrings. Memory consumption should now be proportional to the length of the string. This also avoids quite a few allocations.
With these changes I am finally able to run the benchmark (it used to OOM for me). In conjunction with the other PR, full running time is now under a second.