Reduce parent stat-per-file to stat-per-dir#1839
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kinnison merged 1 commit intorust-lang:masterfrom May 8, 2019
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This is an installation microoptimisation for ~ 3% performance during unpack performance: stat() calls are not free, involving path traversal, ACL checking and so forth. Before: 34s consistently to install rust-docs. After: 32s-33s to install rust-docs. A better still approach would be to handle creation errors by creating the containing directories just in time, but that requires replacing the tar extraction logic, which I haven't yet figured out how to layer in cleanly.
kinnison
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May 8, 2019
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Looks good to me, I'm not bothered about the concern, as you say it's unlikely to be a problem since tarballs are usually semi-sorted thanks to filesystem layout.
| Some(parent) => { | ||
| if !checked_parents.contains(parent) { | ||
| checked_parents.insert(parent.clone().to_owned()); | ||
| // It would be nice to optimise this stat out, but the tar could be like so: |
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One moderately neat way to do that would be to re-use the components iterator from above, joining and checking as you go; but this is sufficient for now
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That would result in stating every element from the top down, which is more than stating from the bottom up.
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(Or I misunderstood :). Thanks for merging it!)
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This is an installation microoptimisation for ~ 3% performance during
unpack performance: stat() calls are not free, involving path traversal,
ACL checking and so forth.
Before: 34s consistently to install rust-docs.
After: 32s-33s to install rust-docs.
A better still approach would be to handle creation errors by creating
the containing directories just in time, but that requires replacing
the tar extraction logic, which I haven't yet figured out how to layer
in cleanly.