From: Jeff Hostetler Date: Thu, 01 Jul 2021 14:20:29 GMT Subject: Re: What's cooking in git.git (Jun 2021, #07; Wed, 30) Message-ID: <4d72a3d6-397e-e55b-cc11-5591070d5e27@jeffhostetler.com> In-Reply-To: <87r1gicfh1.fsf@evledraar.gmail.com> On 7/1/21 9:42 AM, Ævar Arnfjörð Bjarmason wrote: > > On Wed, Jun 30 2021, Junio C Hamano wrote: > >> * jh/builtin-fsmonitor (2021-05-24) 30 commits >> - t/perf: avoid copying builtin fsmonitor files into test repo >> - t7527: test status with untracked-cache and fsmonitor--daemon >> - p7519: add fsmonitor--daemon >> - t7527: create test for fsmonitor--daemon >> - fsmonitor: force update index after large responses >> - fsmonitor: enhance existing comments >> - fsmonitor--daemon: use a cookie file to sync with file system >> - fsmonitor--daemon: periodically truncate list of modified files >> - fsmonitor--daemon: implement handle_client callback >> - fsmonitor-fs-listen-macos: implement FSEvent listener on MacOS >> - fsmonitor-fs-listen-macos: add macos header files for FSEvent >> - fsmonitor-fs-listen-win32: implement FSMonitor backend on Windows >> - fsmonitor--daemon: create token-based changed path cache >> - fsmonitor--daemon: define token-ids >> - fsmonitor--daemon: add pathname classification >> - fsmonitor--daemon: implement daemon command options >> - fsmonitor-fs-listen-macos: stub in backend for MacOS >> - fsmonitor-fs-listen-win32: stub in backend for Windows >> - t/helper/fsmonitor-client: create IPC client to talk to FSMonitor Daemon >> - fsmonitor--daemon: implement client command options >> - fsmonitor--daemon: add a built-in fsmonitor daemon >> - fsmonitor: introduce `core.useBuiltinFSMonitor` to call the daemon via IPC >> - config: FSMonitor is repository-specific >> - help: include fsmonitor--daemon feature flag in version info >> - fsmonitor-ipc: create client routines for git-fsmonitor--daemon >> - fsmonitor--daemon: update fsmonitor documentation >> - fsmonitor--daemon: man page >> - simple-ipc: preparations for supporting binary messages. >> - Merge branch 'jk/perf-in-worktrees' into HEAD >> - Merge branch 'jh/simple-ipc' into jh/rfc-builtin-fsmonitor >> >> An attempt to write and ship with a watchman equivalent tailored >> for our use. >> >> What's the status of this one? > > I think Johannes's reply to the last WC applies[1]: > > I am not Jeff, but I know that he is busy getting back to it, and > plans on submitting a third iteration. > > FWIW I'm still curious about some details on the performance concerns > that seem to have prompted this built-in fsmonitor endeavor, as I asked > about (but didn't get a reply to) in [2]. > > Not as a "we shouldn't have this, let's keep using the hook", but just > curiosity about why we've seemingly gotten such different performance > numbers on the watchman hook v.s. a built-in approach. > > I suspect (but don't know) that the reason is that the built-in is > perhaps integrating differently with git somehow, in a way that we could > retrofit the hook approach to also do (if anyone still cares about the > hook approach). > > In any case I'm interested in *why* the new approach is faster, given > that I've done some testing (again, noted in [2]) that suggest that > bottleneck in the previous pipeline wasn't at all what Jeff H. thought > it was. > > 1. https://lore.kernel.org/git/nycvar.QRO.7.76.6.2106171135530.57@tvgsbejvaqbjf.bet/#t > 2. https://lore.kernel.org/git/87h7lgfchm.fsf@evledraar.gmail.com/ > A quick reply here of Junio's question. Yes, I'm working on a V3 to submit (any day now -- $DAYJOB notwithstanding (read: meetings)). I'll push this up and then try to answer the perf questions. Thanks for your patience. Jeff