perf: Avoid re-canonicalizing the entire IntervalSet on push#1308
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perf: Avoid re-canonicalizing the entire IntervalSet on push#1308Marwes wants to merge 2 commits into
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Canonicalize is taking up a significant amount due to a regex with a huge amount of character ranges (generated by [lalrpop](https://github.com/lalrpop/lalrpop)'s lexer expanding multiple `\w` in a token). While this could perhaps be fixed in lalrpop I did notice the TODO in the code and after addressing this so we automatically union and compress on each push instead of re-canonicalizing on every push and that fixed the performance problem. I did see the earlier attempt at this rust-lang#1051 and it seems like that was reverted and regression tests were added so I hope that and the existing tests are enough (I don't have a clear idea on what tests might be missing).
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I have done some optimization around the code where this occurs which brings up |
BurntSushi
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Hi! Yes, thank you and apologies for the late reply.
The change here itself looks good to me. Thank you for working through this subtle optimization. :-) I have only minor nits on this PR and a request.
Could you add a benchmark to rebar? I think probably this directory is the place to add it. And if you could show a before-and-after on the rebar results here, that would be great.
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Just noticed the comment while doing rust-lang#1308 but I don't have any actual case where this shows up as performance problem. I would argue the code is simpler though so perhaps just simpler code and removal of a "TODO" comment is good.
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Just noticed the comment while doing rust-lang#1308 but I don't have any actual case where this shows up as performance problem. Arguably the code is simpler though so perhaps that and the removal of a "TODO" comment is good.
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Canonicalize is taking up a significant amount due to a regex with a huge amount of character ranges (generated by lalrpop's lexer expanding multiple
\win a token). While this could perhaps be fixed in lalrpop I did notice the TODO in the code and after addressing this so we automatically union and compress on each push instead of re-canonicalizing on every push and that fixed the performance problem.I did see the earlier attempt at this #1051 and it seems like that was reverted and regression tests were added so I hope that and the existing tests are enough (I don't have a clear idea on what tests might be missing).