On Thu, Jun 20, 2024 at 10:12 AM Derrick Stolee via GitGitGadget
<gitgitgadget@xxxxxxxxx> wrote:
>
> From: Derrick Stolee <stolee@xxxxxxxxx>
>
> 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@xxxxxxxxx>
> ---
> sparse-index.c | 7 +++++++
> 1 file changed, 7 insertions(+)
>
> diff --git a/sparse-index.c b/sparse-index.c
> index fec4f393360..8577fa726b8 100644
> --- a/sparse-index.c
> +++ b/sparse-index.c
> @@ -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);
> --
> gitgitgadget
Makes sense. I'm getting really curious to see how this all fits into
the big improvements you made; I guess I'll see that in the next
patch...
