sparse-index: count lstat() calls

The clear_skip_worktree.. methods already report some statistics about
how many cache entries are checked against path_found() due to having
the skip-worktree bit set. However, due to path_found() performing some
caching, this isn't the only information that would be helpful to
report.

Add a new lstat_count member to the path_found_data struct to count the
number of times path_found() calls lstat(). This will be helpful to help
explain performance problems in this method as well as to demonstrate
future changes to the caching algorithm in a more concrete way than
end-to-end timings.

Signed-off-by: Derrick Stolee <stolee@gmail.com>
Reviewed-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
This commit is contained in:
Derrick Stolee
2024-06-28 12:43:24 +00:00
committed by Junio C Hamano
parent 23dd6f8bcc
commit c4e8c42c19

View File

@ -442,6 +442,7 @@ void ensure_correct_sparsity(struct index_state *istate)
struct path_found_data {
struct strbuf dir;
int dir_found;
size_t lstat_count;
};
#define PATH_FOUND_DATA_INIT { \
@ -469,6 +470,7 @@ static int path_found(const char *path, struct path_found_data *data)
/*
* If path itself exists, return 1.
*/
data->lstat_count++;
if (!lstat(path, &st))
return 1;
@ -493,6 +495,7 @@ static int path_found(const char *path, struct path_found_data *data)
strbuf_reset(&data->dir);
strbuf_add(&data->dir, path, newdir - path + 1);
data->lstat_count++;
data->dir_found = !lstat(data->dir.buf, &st);
return 0;
@ -524,6 +527,8 @@ static int clear_skip_worktree_from_present_files_sparse(struct index_state *ist
trace2_data_intmax("index", istate->repo,
"sparse_path_count", path_count);
trace2_data_intmax("index", istate->repo,
"sparse_lstat_count", data.lstat_count);
trace2_region_leave("index", "clear_skip_worktree_from_present_files_sparse",
istate->repo);
clear_path_found_data(&data);
@ -553,6 +558,8 @@ static void clear_skip_worktree_from_present_files_full(struct index_state *ista
trace2_data_intmax("index", istate->repo,
"full_path_count", path_count);
trace2_data_intmax("index", istate->repo,
"full_lstat_count", data.lstat_count);
trace2_region_leave("index", "clear_skip_worktree_from_present_files_full",
istate->repo);
clear_path_found_data(&data);