On Wed, Nov 25, 2015 at 10:00 AM, Ævar Arnfjörð Bjarmason <avarab@xxxxxxxxx> wrote: > On Wed, Nov 25, 2015 at 7:35 AM, Christian Couder > <christian.couder@xxxxxxxxx> wrote: >> At Booking.com we know that mtime works everywhere and we don't >> want the untracked cache to stop working when a kernel is upgraded >> or when the repo is copied to a machine with a different kernel. >> I will add tests later if people are ok with this. > > I bit more info: I rolled Git out internally with this patch: > https://github.com/avar/git/commit/c63f7c12c2664631961add7cf3da901b0b6aa2f2 > > The --untracked-cache feature hardcodes the equivalent of: > > pwd; uname --kernel-name --kernel-release --kernel-version > > Into the index. If any of those change it prints out the "cache is > disabled" warning. > > This patch will make it stop being so afraid of itself to the point of > disabling itself on minor kernel upgrades :) The problem is, there's no way to teach git to know it's a "minor" upgrade.. but if there is a config key to say "don't be paranoid, I know what I'm doing", then we can skip that check, or just warn instead of disabling the cache. > A few other issues with this feature I've noticed: > > * There's no way to just enable it globally via the config. Makes it > a bit of a hassle to use it. I wanted to have a config option to > enable it via the config, how about "index.untracked_cache = true" for > the config variable name? If you haven't noticed, all these experimental features have no real UI (update-index is plumbing). I have been waiting for someone like you to start using it and figure out the best UI (then implement it) ;) > * Doing "cd /tmp: git --git-dir=/git/somewhere/else/.git update-index > --untracked-cache" doesn't work how I'd expect. It hardcodes "/tmp" as > the directory that "works" into the index, so if you use the working > tree you'll never use the untracked cache. I spotted this because I > carry out a bunch of git maintenance commands with --git-dir instead > of cd-ing to the relevant directories. This works for most other > things in git, is it a bug that it doesn't work here? It needs the current directory at --untrack-cache time to test if the directory satisfies the requirements. So either you cd to that worktree, or you have to specify --worktree as well. Or am I missing something? > * If you "ctrl+c" git update-index --untracked-cache at an > inopportune time you'll end up with a mtime-test-XXXXXX directory in > your working tree. Perhaps this tempdir should be created in the .git > directory instead? No because in theory .git could be on a separate file system with different semantics. But we should probably clean those files at ^C. > * Maybe we should have a --test-untracked-cache option, so you can > run the tests without enabling it. I'd say patches welcome. > Aside from the slight hassle of enabling this and keeping it enabled > this feature is great. It's sped up "git status" across the board by > about 40%. Slightly less than that on faster spinning disks, slightly > more than that on slower ones. I'm still waiting for the day when watchman support gets merged and maybe poke Facebook guys to compare performance with Mercurial :) Well, we are probably still behind Mercurial on that day. Also, there's still work to be done. Right now it's optimized for whole-tree "git status", Doing "git status -- abc" will not benefit from untracked cache, similarly "git add" with pathspec.. -- Duy -- To unsubscribe from this list: send the line "unsubscribe git" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html