On Thu, Aug 29, 2024 at 11:43:40PM +0300, Roman Sandu wrote: > Good day! > > I have a decently sized (80K files) monorepo on an NTFS drive that I have > been working with for a while under Windows via git-for-windows. Recently, I > had to (temporarily) switch to Ubuntu (24.04) via dual-boot for irrelevant > reasons, and I decided that simply mounting my NTFS drive and using the > monorepo from Ubuntu is a great idea, actually, as NTFS-3G allow for > seamless interop with NTFS via UserMapping. And so that is exactly what I > did and It Just Works! > > Except it kind of does not. Every time I run `git status` it takes 8 > seconds, which is very painful when doing tricky history rewriting. > > To diagnose the problem, I ran git status with GIT_TRACE_PERFORMANCE > enabled, and what I see is that the "refresh index" region is taking up 99% > of the time. Digging further, `strace -fc git status` tells me that 99% of > the time is spent on newfstatat'ing files. Okay, makes sense, stat'ing files > through FUSE is not all that quick. But how many files are we talking about? > My repository has `feature.manyFiles` enabled in git, so I would expect > `core.untrackedCache` make it so that `git status` skips basically > everything except for the root folder which contains, what, 20 subfolders? > But it actually does >96K stat calls! Which is more than the amount of files > in the repository in total. Briefly looking at the output of `strace -f git > status`, I see that git indeed goes through basically all of the repository, > even things that have not changed for years, as if `core.untrackedCache` is > not actually enabled. Manually enabling it on top of `feature.manyFiles` > does not help. Note that `git update-index --test-untracked-cache` tells me > that mtime does indeed work, and I've also manually stat'ed some folders > which `git status` re-stats on every run and I see that the modify time is > indeed a couple of hours ago, yet even when running `git status` several > times in a row it re-scans the entire folder every time. > > So, what do I do about this? It honestly looks like a git bug to me, maybe > it silently fails to update the index with new timestamps because it was > initially created on Windows? But I have no clue how to narrow this issue > down further, so any ideas or suggestions would be appreciated! > It was pretty big news that Paragon's read-write NTFS driver was merged into the kernel. You might want to give that a try if your main problem is performance. https://lore.kernel.org/lkml/CAHk-=wjn4W-7ZbHrw08cWy=12DgheFUKLO5YLgG6in5TA5HxqQ@xxxxxxxxxxxxxx/ Regards, Vito Caputo
