b88f89c1ef
A quick benchmark of whereis shows not much speed improvement, maybe a few percent. Profiling it found a hotspot, adds to todo.
34 lines
1.7 KiB
Markdown
34 lines
1.7 KiB
Markdown
git-annex uses FilePath (String) extensively. That's a slow data type.
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Converting to ByteString, and RawFilePath, should speed it up
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significantly, according to [[/profiling]].
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I've made a test branch, `bs`, to see what kind of performance improvement
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to expect. Most commands don't built yet in that branch, but `git annex
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find` does. Speedups range from 28-66%. The files fly by much more
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snappily.
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As well as adding back all the code that was disabled to get it to build,
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the `bs` branch has quite a lot of things still needing work, including:
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* Eliminate all the fromRawFilePath, toRawFilePath, encodeBS,
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decodeBS conversions. Or at least most of them. There are likely
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quite a few places where a value is converted back and forth several times.
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As a first step, profile and look for the hot spots. Known hot spots:
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* keyFile uses fromRawFilePath and that adds around 3% overhead in `git-annex find`.
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Converting it to a RawFilePath needs a version of `</>` for RawFilePaths.
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* getJournalFileStale uses fromRawFilePath, and adds 3-5% overhead in
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`git-annex whereis`. Converting it to RawFilePath needs a version of `</>` for RawFilePaths.
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* System.FilePath is not available for RawFilePath, and many of the
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conversions are to get a FilePath in order to use that library.
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It should be entirely straightforward to make a version of System.FilePath
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that can operate on RawFilePath, except possibly there could be some
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complications due to Windows.
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* Use versions of IO actions like getFileStatus that take a RawFilePath,
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avoiding a conversion. Note that these are only available on unix, not
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windows, so a compatability shim will be needed.
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(I can't seem to find any library that provides one.)
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