Re: [PATCH 1/1] fetch: add trace2 instrumentation

> From: Erik Chen <erikchen@chromium.org>
>
> Add trace2 regions to fetch-pack.c to better track time spent in the various
> phases of a fetch:
>
>     * matching common remote and local refs
>     * marking local refs as complete (part of the matching process)
>
> Both of these stages can be slow for repositories with many refs.
>
> Signed-off-by: Erik Chen <erikchen@chromium.org>
> ---
>  fetch-pack.c | 9 ++++++++-
>  1 file changed, 8 insertions(+), 1 deletion(-)
>
> diff --git a/fetch-pack.c b/fetch-pack.c
> index 0130b44112..f2f3365bbe 100644
> --- a/fetch-pack.c
> +++ b/fetch-pack.c
> @@ -666,9 +666,10 @@ static void mark_complete_and_common_ref(struct fetch_negotiator *negotiator,
>  	struct ref *ref;
>  	int old_save_commit_buffer = save_commit_buffer;
>  	timestamp_t cutoff = 0;
> -

>  	save_commit_buffer = 0;
>
> +	trace2_region_enter("fetch-pack", "mark_complete_and_common_ref", NULL);
> +
>  	for (ref = *refs; ref; ref = ref->next) {
>  		struct object *o;
>
> @@ -690,6 +691,10 @@ static void mark_complete_and_common_ref(struct fetch_negotiator *negotiator,
>  		}
>  	}
>
> +	/* This block marks all local refs as COMPLETE, and then recursively marks all
> +	 * parents of those refs as COMPLETE.
> +	 */
> +	trace2_region_enter("fetch-pack", "mark_complete_local_refs", NULL);
>  	if (!args->deepen) {
>  		for_each_ref(mark_complete_oid, NULL);
>  		for_each_cached_alternate(NULL, mark_alternate_complete);
> @@ -697,6 +702,7 @@ static void mark_complete_and_common_ref(struct fetch_negotiator *negotiator,
>  		if (cutoff)
>  			mark_recent_complete_commits(args, cutoff);
>  	}
> +	trace2_region_leave("fetch-pack", "mark_complete_local_refs", NULL);
>
>  	/*
>  	 * Mark all complete remote refs as common refs.
> @@ -716,6 +722,7 @@ static void mark_complete_and_common_ref(struct fetch_negotiator *negotiator,
>  	}
>
>  	save_commit_buffer = old_save_commit_buffer;
> +	trace2_region_leave("fetch-pack", "mark_complete_and_common_ref", NULL);
>  }
>
>  /*
> --
> gitgitgadget
>