Merge branch 'vd/skip-cache-tree-update'

Avoid calling 'cache_tree_update()' when doing so would be redundant.

* vd/skip-cache-tree-update:
  rebase: use 'skip_cache_tree_update' option
  read-tree: use 'skip_cache_tree_update' option
  reset: use 'skip_cache_tree_update' option
  unpack-trees: add 'skip_cache_tree_update' option
  cache-tree: add perf test comparing update and prime

Makefile

@@ -787,6 +787,7 @@ TEST_BUILTINS_OBJS += test-advise.o
 TEST_BUILTINS_OBJS += test-bitmap.o
 TEST_BUILTINS_OBJS += test-bloom.o
 TEST_BUILTINS_OBJS += test-bundle-uri.o
+TEST_BUILTINS_OBJS += test-cache-tree.o
 TEST_BUILTINS_OBJS += test-chmtime.o
 TEST_BUILTINS_OBJS += test-config.o
 TEST_BUILTINS_OBJS += test-crontab.o

builtin/read-tree.c

@@ -249,6 +249,10 @@ int cmd_read_tree(int argc, const char **argv, const char *cmd_prefix)
 	if (opts.debug_unpack)
 		opts.fn = debug_merge;
 
+	/* If we're going to prime_cache_tree later, skip cache tree update */
+	if (nr_trees == 1 && !opts.prefix)
+		opts.skip_cache_tree_update = 1;
+
 	cache_tree_free(&active_cache_tree);
 	for (i = 0; i < nr_trees; i++) {
 		struct tree *tree = trees[i];

builtin/reset.c

@@ -73,9 +73,11 @@ static int reset_index(const char *ref, const struct object_id *oid, int reset_t
 	case HARD:
 		opts.update = 1;
 		opts.reset = UNPACK_RESET_OVERWRITE_UNTRACKED;
+		opts.skip_cache_tree_update = 1;
 		break;
 	case MIXED:
 		opts.reset = UNPACK_RESET_PROTECT_UNTRACKED;
+		opts.skip_cache_tree_update = 1;
 		/* but opts.update=0, so working tree not updated */
 		break;
 	default:

reset.c

@@ -128,6 +128,7 @@ int reset_head(struct repository *r, const struct reset_head_opts *opts)
 	unpack_tree_opts.update = 1;
 	unpack_tree_opts.merge = 1;
 	unpack_tree_opts.preserve_ignored = 0; /* FIXME: !overwrite_ignore */
+	unpack_tree_opts.skip_cache_tree_update = 1;
 	init_checkout_metadata(&unpack_tree_opts.meta, switch_to_branch, oid, NULL);
 	if (reset_hard)
 		unpack_tree_opts.reset = UNPACK_RESET_PROTECT_UNTRACKED;

sequencer.c

@@ -3748,6 +3748,7 @@ static int do_reset(struct repository *r,
 	unpack_tree_opts.merge = 1;
 	unpack_tree_opts.update = 1;
 	unpack_tree_opts.preserve_ignored = 0; /* FIXME: !overwrite_ignore */
+	unpack_tree_opts.skip_cache_tree_update = 1;
 	init_checkout_metadata(&unpack_tree_opts.meta, name, &oid, NULL);
 
 	if (repo_read_index_unmerged(r)) {

t/helper/test-cache-tree.c

@@ -0,0 +1,64 @@
+#include "test-tool.h"
+#include "cache.h"
+#include "tree.h"
+#include "cache-tree.h"
+#include "parse-options.h"
+
+static char const * const test_cache_tree_usage[] = {
+	N_("test-tool cache-tree <options> (control|prime|update)"),
+	NULL
+};
+
+int cmd__cache_tree(int argc, const char **argv)
+{
+	struct object_id oid;
+	struct tree *tree;
+	int empty = 0;
+	int invalidate_qty = 0;
+	int i;
+
+	struct option options[] = {
+		OPT_BOOL(0, "empty", &empty,
+			 N_("clear the cache tree before each iteration")),
+		OPT_INTEGER_F(0, "invalidate", &invalidate_qty,
+			      N_("number of entries in the cache tree to invalidate (default 0)"),
+			      PARSE_OPT_NONEG),
+		OPT_END()
+	};
+
+	setup_git_directory();
+
+	argc = parse_options(argc, argv, NULL, options, test_cache_tree_usage, 0);
+
+	if (read_cache() < 0)
+		die(_("unable to read index file"));
+
+	oidcpy(&oid, &the_index.cache_tree->oid);
+	tree = parse_tree_indirect(&oid);
+	if (!tree)
+		die(_("not a tree object: %s"), oid_to_hex(&oid));
+
+	if (empty) {
+		/* clear the cache tree & allocate a new one */
+		cache_tree_free(&the_index.cache_tree);
+		the_index.cache_tree = cache_tree();
+	} else if (invalidate_qty) {
+		/* invalidate the specified number of unique paths */
+		float f_interval = (float)the_index.cache_nr / invalidate_qty;
+		int interval = f_interval < 1.0 ? 1 : (int)f_interval;
+		for (i = 0; i < invalidate_qty && i * interval < the_index.cache_nr; i++)
+			cache_tree_invalidate_path(&the_index, the_index.cache[i * interval]->name);
+	}
+
+	if (argc != 1)
+		usage_with_options(test_cache_tree_usage, options);
+	else if (!strcmp(argv[0], "prime"))
+		prime_cache_tree(the_repository, &the_index, tree);
+	else if (!strcmp(argv[0], "update"))
+		cache_tree_update(&the_index, WRITE_TREE_SILENT | WRITE_TREE_REPAIR);
+	/* use "control" subcommand to specify no-op */
+	else if (!!strcmp(argv[0], "control"))
+		die(_("Unhandled subcommand '%s'"), argv[0]);
+
+	return 0;
+}

t/helper/test-tool.c

@@ -14,6 +14,7 @@ static struct test_cmd cmds[] = {
 	{ "bitmap", cmd__bitmap },
 	{ "bloom", cmd__bloom },
 	{ "bundle-uri", cmd__bundle_uri },
+	{ "cache-tree", cmd__cache_tree },
 	{ "chmtime", cmd__chmtime },
 	{ "config", cmd__config },
 	{ "crontab", cmd__crontab },

t/helper/test-tool.h

@@ -8,6 +8,7 @@ int cmd__advise_if_enabled(int argc, const char **argv);
 int cmd__bitmap(int argc, const char **argv);
 int cmd__bloom(int argc, const char **argv);
 int cmd__bundle_uri(int argc, const char **argv);
+int cmd__cache_tree(int argc, const char **argv);
 int cmd__chmtime(int argc, const char **argv);
 int cmd__config(int argc, const char **argv);
 int cmd__crontab(int argc, const char **argv);

t/perf/p0006-read-tree-checkout.sh

@@ -49,6 +49,14 @@ test_perf "read-tree br_base br_ballast ($nr_files)" '
 	git read-tree -n -m br_base br_ballast
 '
 
+test_perf "read-tree br_ballast_plus_1 ($nr_files)" '
+	# Run read-tree 100 times for clearer performance results & comparisons
+	for i in  $(test_seq 100)
+	do
+		git read-tree -n -m br_ballast_plus_1 || return 1
+	done
+'
+
 test_perf "switch between br_base br_ballast ($nr_files)" '
 	git checkout -q br_base &&
 	git checkout -q br_ballast

t/perf/p0090-cache-tree.sh

@@ -0,0 +1,36 @@
+#!/bin/sh
+
+test_description="Tests performance of cache tree update operations"
+
+. ./perf-lib.sh
+
+test_perf_large_repo
+test_checkout_worktree
+
+count=100
+
+test_expect_success 'setup cache tree' '
+	git write-tree
+'
+
+test_cache_tree () {
+	test_perf "$1, $3" "
+		for i in \$(test_seq $count)
+		do
+			test-tool cache-tree $4 $2
+		done
+	"
+}
+
+test_cache_tree_update_functions () {
+	test_cache_tree 'no-op' 'control' "$1" "$2"
+	test_cache_tree 'prime_cache_tree' 'prime' "$1" "$2"
+	test_cache_tree 'cache_tree_update' 'update' "$1" "$2"
+}
+
+test_cache_tree_update_functions "clean" ""
+test_cache_tree_update_functions "invalidate 2" "--invalidate 2"
+test_cache_tree_update_functions "invalidate 50" "--invalidate 50"
+test_cache_tree_update_functions "empty" "--empty"
+
+test_done

t/perf/p7102-reset.sh

@@ -0,0 +1,21 @@
+#!/bin/sh
+
+test_description='performance of reset'
+. ./perf-lib.sh
+
+test_perf_default_repo
+test_checkout_worktree
+
+test_perf 'reset --hard with change in tree' '
+	base=$(git rev-parse HEAD) &&
+	test_commit --no-tag A &&
+	new=$(git rev-parse HEAD) &&
+
+	for i in $(test_seq 10)
+	do
+		git reset --hard $new &&
+		git reset --hard $base || return $?
+	done
+'
+
+test_done

t/t1022-read-tree-partial-clone.sh

@@ -19,7 +19,7 @@ test_expect_success 'read-tree in partial clone prefetches in one batch' '
 	git -C server config uploadpack.allowfilter 1 &&
 	git -C server config uploadpack.allowanysha1inwant 1 &&
 	git clone --bare --filter=blob:none "file://$(pwd)/server" client &&
-	GIT_TRACE_PACKET="$(pwd)/trace" git -C client read-tree $TREE &&
+	GIT_TRACE_PACKET="$(pwd)/trace" git -C client read-tree $TREE $TREE &&
 
 	# "done" marks the end of negotiation (once per fetch). Expect that
 	# only one fetch occurs.

unpack-trees.c

@@ -2043,7 +2043,8 @@ int unpack_trees(unsigned len, struct tree_desc *t, struct unpack_trees_options
 		if (!ret) {
 			if (git_env_bool("GIT_TEST_CHECK_CACHE_TREE", 0))
 				cache_tree_verify(the_repository, &o->result);
-			if (!cache_tree_fully_valid(o->result.cache_tree))
+			if (!o->skip_cache_tree_update &&
+			    !cache_tree_fully_valid(o->result.cache_tree))
 				cache_tree_update(&o->result,
 						  WRITE_TREE_SILENT |
 						  WRITE_TREE_REPAIR);

unpack-trees.h

@@ -71,7 +71,8 @@ struct unpack_trees_options {
 		     quiet,
 		     exiting_early,
 		     show_all_errors,
-		     dry_run;
+		     dry_run,
+		     skip_cache_tree_update;
 	enum unpack_trees_reset_type reset;
 	const char *prefix;
 	int cache_bottom;