checkout: Create directories similar to and consider using a cache #343
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44 tasks
Byron
changed the title
Byron
changed the title
The windows file check needs to handle relative links properly when checking for file type.
For now just with empty files, but that shows that with a single thread it's faster than git at 27k files per second created compared to 14.5k of a single thread of git. We do the least amount of work necessary even without an lstat cache, but that probably changes once we have to access the ODB to obtain actual data. Note that git might also do an additional exists check per file to see if it changed, something we don't do as we may assume exclusive access to the directory and just go with that for now. Long story short: it looks like there is a lot of potential for performance improvements and I think there is a lot of room for being faster especially in multi-threaded mode.
This should tell us how much time it really takes to do the ODB part, and see how much we could save by optimizing disk access, for instance by using an lstat cache.
Git is able to use relative paths by changing the working directory. See https://github.com/git/git/blob/main/builtin.h#L82:L82 We probably shouldn't do that as a library, but will compose the path instead like we do now, but should consider using the cache for file and directory handling to avoid allocations.
This comes at a cost, but hopefully this is justified performance wise but most importantly, makes the upcoming implementation of the lstat cache possible or easier.
We now definitely do extra work in some cases, but save a lot in others thanks to the sorted input.
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A custom
crate_dir_all()with a cache similar to how git does it.Tasks