Sorry for the noise, I've resubmitted this patch on the original
thread (pull.424.v2.git.1572967644.gitgitgadget@xxxxxxxxx).
On Mon, Nov 4, 2019 at 3:41 PM Utsav Shah via GitGitGadget
<gitgitgadget@xxxxxxxxx> wrote:
>
> From: Utsav Shah <utsav@xxxxxxxxxxx>
>
> The index might be aware that a file hasn't modified via fsmonitor, but
> unpack-trees did not pay attention to it and checked via ie_match_stat
> which can be inefficient on certain filesystems. This significantly slows
> down commands that run oneway_merge, like checkout and reset --hard.
>
> This patch makes oneway_merge check whether a file is considered
> unchanged through fsmonitor and skips ie_match_stat on it. unpack-trees
> also now correctly copies over fsmonitor validity state from the source
> index. Finally, for correctness, we force a refresh of fsmonitor state in
> tweak_fsmonitor.
>
> After this change, commands like stash (that use reset --hard
> internally) go from 8s or more to ~2s on a 250k file repository on a
> mac.
>
> Signed-off-by: Utsav Shah <utsav@xxxxxxxxxxx>
> ---
> fsmonitor.c | 20 +++++++++++---------
> t/t7113-post-index-change-hook.sh | 3 ---
> t/t7519-status-fsmonitor.sh | 9 +++++++--
> unpack-trees.c | 6 +++++-
> 4 files changed, 23 insertions(+), 15 deletions(-)
>
> diff --git a/fsmonitor.c b/fsmonitor.c
> index 1f4aa1b150..4362bc6ee9 100644
> --- a/fsmonitor.c
> +++ b/fsmonitor.c
> @@ -55,9 +55,10 @@ int read_fsmonitor_extension(struct index_state *istate, const void *data,
> }
> istate->fsmonitor_dirty = fsmonitor_dirty;
>
> - if (istate->fsmonitor_dirty->bit_size > istate->cache_nr)
> - BUG("fsmonitor_dirty has more entries than the index (%"PRIuMAX" > %u)",
> - (uintmax_t)istate->fsmonitor_dirty->bit_size, istate->cache_nr);
> + if (!istate->split_index && istate->fsmonitor_dirty->bit_size > istate->cache_nr)
> + BUG("fsmonitor_dirty has more entries than the index (%"PRIuMAX" > %"PRIuMAX")",
> + (uintmax_t)istate->fsmonitor_dirty->bit_size, (uintmax_t)istate->cache_nr);
> +
>
> trace_printf_key(&trace_fsmonitor, "read fsmonitor extension successful");
> return 0;
> @@ -83,9 +84,9 @@ void write_fsmonitor_extension(struct strbuf *sb, struct index_state *istate)
> uint32_t ewah_size = 0;
> int fixup = 0;
>
> - if (istate->fsmonitor_dirty->bit_size > istate->cache_nr)
> - BUG("fsmonitor_dirty has more entries than the index (%"PRIuMAX" > %u)",
> - (uintmax_t)istate->fsmonitor_dirty->bit_size, istate->cache_nr);
> + if (!istate->split_index && istate->fsmonitor_dirty->bit_size > istate->cache_nr)
> + BUG("fsmonitor_dirty has more entries than the index (%"PRIuMAX" > %"PRIuMAX")",
> + (uintmax_t)istate->fsmonitor_dirty->bit_size, (uintmax_t)istate->cache_nr);
>
> put_be32(&hdr_version, INDEX_EXTENSION_VERSION);
> strbuf_add(sb, &hdr_version, sizeof(uint32_t));
> @@ -189,6 +190,9 @@ void refresh_fsmonitor(struct index_state *istate)
> }
> if (bol < query_result.len)
> fsmonitor_refresh_callback(istate, buf + bol);
> +
> + if (istate->untracked)
> + istate->untracked->use_fsmonitor = 1;
> } else {
> /* Mark all entries invalid */
> for (i = 0; i < istate->cache_nr; i++)
> @@ -257,9 +261,7 @@ void tweak_fsmonitor(struct index_state *istate)
> (uintmax_t)istate->fsmonitor_dirty->bit_size, istate->cache_nr);
> ewah_each_bit(istate->fsmonitor_dirty, fsmonitor_ewah_callback, istate);
>
> - /* Now mark the untracked cache for fsmonitor usage */
> - if (istate->untracked)
> - istate->untracked->use_fsmonitor = 1;
> + refresh_fsmonitor(istate);
> }
>
> ewah_free(istate->fsmonitor_dirty);
> diff --git a/t/t7113-post-index-change-hook.sh b/t/t7113-post-index-change-hook.sh
> index f011ad7eec..5ca2279d0d 100755
> --- a/t/t7113-post-index-change-hook.sh
> +++ b/t/t7113-post-index-change-hook.sh
> @@ -50,9 +50,6 @@ test_expect_success 'test status, add, commit, others trigger hook without flags
> git checkout -- dir1/file1.txt &&
> test_path_is_file testsuccess && rm -f testsuccess &&
> test_path_is_missing testfailure &&
> - git update-index &&
> - test_path_is_missing testsuccess &&
> - test_path_is_missing testfailure &&
> git reset --soft &&
> test_path_is_missing testsuccess &&
> test_path_is_missing testfailure
> diff --git a/t/t7519-status-fsmonitor.sh b/t/t7519-status-fsmonitor.sh
> index d8df990972..9cac3d3d8e 100755
> --- a/t/t7519-status-fsmonitor.sh
> +++ b/t/t7519-status-fsmonitor.sh
> @@ -106,6 +106,8 @@ EOF
>
> # test that "update-index --fsmonitor-valid" sets the fsmonitor valid bit
> test_expect_success 'update-index --fsmonitor-valid" sets the fsmonitor valid bit' '
> + write_script .git/hooks/fsmonitor-test<<-\EOF &&
> + EOF
> git update-index --fsmonitor &&
> git update-index --fsmonitor-valid dir1/modified &&
> git update-index --fsmonitor-valid dir2/modified &&
> @@ -164,6 +166,8 @@ EOF
>
> # test that newly added files are marked valid
> test_expect_success 'newly added files are marked valid' '
> + write_script .git/hooks/fsmonitor-test<<-\EOF &&
> + EOF
> git add new &&
> git add dir1/new &&
> git add dir2/new &&
> @@ -218,11 +222,12 @@ test_expect_success '*only* files returned by the integration script get flagged
> # Ensure commands that call refresh_index() to move the index back in time
> # properly invalidate the fsmonitor cache
> test_expect_success 'refresh_index() invalidates fsmonitor cache' '
> - write_script .git/hooks/fsmonitor-test<<-\EOF &&
> - EOF
> clean_repo &&
> + write_integration_script &&
> dirty_repo &&
> git add . &&
> + write_script .git/hooks/fsmonitor-test<<-\EOF &&
> + EOF
> git commit -m "to reset" &&
> git reset HEAD~1 &&
> git status >actual &&
> diff --git a/unpack-trees.c b/unpack-trees.c
> index 33ea7810d8..fc5ceb932c 100644
> --- a/unpack-trees.c
> +++ b/unpack-trees.c
> @@ -1504,6 +1504,9 @@ int unpack_trees(unsigned len, struct tree_desc *t, struct unpack_trees_options
> o->merge_size = len;
> mark_all_ce_unused(o->src_index);
>
> + if (o->src_index->fsmonitor_last_update)
> + o->result.fsmonitor_last_update = o->src_index->fsmonitor_last_update;
> +
> /*
> * Sparse checkout loop #1: set NEW_SKIP_WORKTREE on existing entries
> */
> @@ -2384,7 +2387,8 @@ int oneway_merge(const struct cache_entry * const *src,
>
> if (old && same(old, a)) {
> int update = 0;
> - if (o->reset && o->update && !ce_uptodate(old) && !ce_skip_worktree(old)) {
> + if (o->reset && o->update && !ce_uptodate(old) && !ce_skip_worktree(old) &&
> + !(old->ce_flags & CE_FSMONITOR_VALID)) {
> struct stat st;
> if (lstat(old->name, &st) ||
> ie_match_stat(o->src_index, old, &st, CE_MATCH_IGNORE_VALID|CE_MATCH_IGNORE_SKIP_WORKTREE))
> --
> gitgitgadget
