push: add trace2 instrumentation

Add trace2 regions in transport.c and builtin/push.c to better track
time spent in various phases of pushing:

* Listing refs
* Checking submodules
* Pushing submodules
* Pushing refs

Signed-off-by: Josh Steadmon <steadmon@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

builtin/push.c

@@ -357,8 +357,10 @@ static int push_with_options(struct transport *transport, struct refspec *rs,
 
 	if (verbosity > 0)
 		fprintf(stderr, _("Pushing to %s\n"), transport->url);
+	trace2_region_enter("push", "transport_push", the_repository);
 	err = transport_push(the_repository, transport,
 			     rs, flags, &reject_reasons);
+	trace2_region_leave("push", "transport_push", the_repository);
 	if (err != 0) {
 		fprintf(stderr, "%s", push_get_color(PUSH_COLOR_ERROR));
 		error(_("failed to push some refs to '%s'"), transport->url);

transport.c

@@ -1145,8 +1145,10 @@ int transport_push(struct repository *r,
 
 		refspec_ref_prefixes(rs, &ref_prefixes);
 
+		trace2_region_enter("transport_push", "get_refs_list", the_repository);
 		remote_refs = transport->vtable->get_refs_list(transport, 1,
 							       &ref_prefixes);
+		trace2_region_leave("transport_push", "get_refs_list", the_repository);
 
 		argv_array_clear(&ref_prefixes);
 
@@ -1182,6 +1184,7 @@ int transport_push(struct repository *r,
 			struct ref *ref = remote_refs;
 			struct oid_array commits = OID_ARRAY_INIT;
 
+			trace2_region_enter("transport_push", "push_submodules", the_repository);
 			for (; ref; ref = ref->next)
 				if (!is_null_oid(&ref->new_oid))
 					oid_array_append(&commits,
@@ -1194,9 +1197,11 @@ int transport_push(struct repository *r,
 						      transport->push_options,
 						      pretend)) {
 				oid_array_clear(&commits);
+				trace2_region_leave("transport_push", "push_submodules", the_repository);
 				die(_("failed to push all needed submodules"));
 			}
 			oid_array_clear(&commits);
+			trace2_region_leave("transport_push", "push_submodules", the_repository);
 		}
 
 		if (((flags & TRANSPORT_RECURSE_SUBMODULES_CHECK) ||
@@ -1207,6 +1212,7 @@ int transport_push(struct repository *r,
 			struct string_list needs_pushing = STRING_LIST_INIT_DUP;
 			struct oid_array commits = OID_ARRAY_INIT;
 
+			trace2_region_enter("transport_push", "check_submodules", the_repository);
 			for (; ref; ref = ref->next)
 				if (!is_null_oid(&ref->new_oid))
 					oid_array_append(&commits,
@@ -1217,15 +1223,19 @@ int transport_push(struct repository *r,
 						     transport->remote->name,
 						     &needs_pushing)) {
 				oid_array_clear(&commits);
+				trace2_region_leave("transport_push", "check_submodules", the_repository);
 				die_with_unpushed_submodules(&needs_pushing);
 			}
 			string_list_clear(&needs_pushing, 0);
 			oid_array_clear(&commits);
+			trace2_region_leave("transport_push", "check_submodules", the_repository);
 		}
 
-		if (!(flags & TRANSPORT_RECURSE_SUBMODULES_ONLY))
+		if (!(flags & TRANSPORT_RECURSE_SUBMODULES_ONLY)) {
+			trace2_region_enter("transport_push", "push_refs", the_repository);
 			push_ret = transport->vtable->push_refs(transport, remote_refs, flags);
-		else
+			trace2_region_leave("transport_push", "push_refs", the_repository);
+		} else
 			push_ret = 0;
 		err = push_had_errors(remote_refs);
 		ret = push_ret | err;