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* [PATCH] fetch: only run 'gc' once when fetching multiple remotes
@ 2019-06-19  9:46 Nguyễn Thái Ngọc Duy
  2019-06-19 10:26 ` [RFC/PATCH] gc: run more pre-detach operations under lock Ævar Arnfjörð Bjarmason
  2019-06-19 18:59 ` [PATCH] fetch: only run 'gc' once when fetching multiple remotes Jeff King
  0 siblings, 2 replies; 61+ messages in thread
From: Nguyễn Thái Ngọc Duy @ 2019-06-19  9:46 UTC (permalink / raw)
  To: git; +Cc: Nguyễn Thái Ngọc Duy

In multiple remotes mode, git-fetch is launched for n-1 remotes and the
last remote is handled by the current process. Each of these processes
will in turn run 'gc' at the end.

This is not really a problem because even if multiple 'gc --auto' is run
at the same time we still handle it correctly. It does show multiple
"auto packing in the background" messages though. And we may waste some
resources when gc actually runs because we still do some stuff before
checking the lock and moving it to background.

So let's try to avoid that. We should only need one 'gc' run after all
objects and references are added anyway. Add a new option --no-auto-gc
that will be used by those n-1 processes. 'gc --auto' will always run on
the main fetch process (*).

(*) even if we fetch remotes in parallel at some point in future, this
    should still be fine because we should "join" all those processes
    before this step.

Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
---
 Documentation/fetch-options.txt |  4 ++++
 builtin/fetch.c                 | 17 +++++++++++------
 t/t5514-fetch-multiple.sh       |  7 +++++--
 3 files changed, 20 insertions(+), 8 deletions(-)

diff --git a/Documentation/fetch-options.txt b/Documentation/fetch-options.txt
index 91c47752ec..592f391298 100644
--- a/Documentation/fetch-options.txt
+++ b/Documentation/fetch-options.txt
@@ -88,6 +88,10 @@ ifndef::git-pull[]
 	Allow several <repository> and <group> arguments to be
 	specified. No <refspec>s may be specified.
 
+--[no-]auto-gc::
+	Run `git gc --auto` at the end to perform garbage collection
+	if needed. This is enabled by default.
+
 -p::
 --prune::
 	Before fetching, remove any remote-tracking references that no
diff --git a/builtin/fetch.c b/builtin/fetch.c
index 4ba63d5ac6..6a3c507897 100644
--- a/builtin/fetch.c
+++ b/builtin/fetch.c
@@ -48,6 +48,7 @@ static int prune_tags = -1; /* unspecified */
 
 static int all, append, dry_run, force, keep, multiple, update_head_ok, verbosity, deepen_relative;
 static int progress = -1;
+static int enable_auto_gc = 1;
 static int tags = TAGS_DEFAULT, unshallow, update_shallow, deepen;
 static int max_children = 1;
 static enum transport_family family;
@@ -169,6 +170,8 @@ static struct option builtin_fetch_options[] = {
 	OPT_STRING_LIST(0, "negotiation-tip", &negotiation_tip, N_("revision"),
 			N_("report that we have only objects reachable from this object")),
 	OPT_PARSE_LIST_OBJECTS_FILTER(&filter_options),
+	OPT_BOOL(0, "auto-gc", &enable_auto_gc,
+		 N_("run 'gc --auto' after fetching")),
 	OPT_END()
 };
 
@@ -1424,7 +1427,7 @@ static int fetch_multiple(struct string_list *list)
 			return errcode;
 	}
 
-	argv_array_pushl(&argv, "fetch", "--append", NULL);
+	argv_array_pushl(&argv, "fetch", "--append", "--no-auto-gc", NULL);
 	add_options_to_argv(&argv);
 
 	for (i = 0; i < list->nr; i++) {
@@ -1674,11 +1677,13 @@ int cmd_fetch(int argc, const char **argv, const char *prefix)
 
 	close_all_packs(the_repository->objects);
 
-	argv_array_pushl(&argv_gc_auto, "gc", "--auto", NULL);
-	if (verbosity < 0)
-		argv_array_push(&argv_gc_auto, "--quiet");
-	run_command_v_opt(argv_gc_auto.argv, RUN_GIT_CMD);
-	argv_array_clear(&argv_gc_auto);
+	if (enable_auto_gc) {
+		argv_array_pushl(&argv_gc_auto, "gc", "--auto", NULL);
+		if (verbosity < 0)
+			argv_array_push(&argv_gc_auto, "--quiet");
+		run_command_v_opt(argv_gc_auto.argv, RUN_GIT_CMD);
+		argv_array_clear(&argv_gc_auto);
+	}
 
 	return result;
 }
diff --git a/t/t5514-fetch-multiple.sh b/t/t5514-fetch-multiple.sh
index 0030c92e1a..5426d4b5ab 100755
--- a/t/t5514-fetch-multiple.sh
+++ b/t/t5514-fetch-multiple.sh
@@ -105,9 +105,12 @@ test_expect_success 'git fetch --multiple (two remotes)' '
 	 git remote rm origin &&
 	 git remote add one ../one &&
 	 git remote add two ../two &&
-	 git fetch --multiple one two &&
+	 GIT_TRACE=1 git fetch --multiple one two 2>trace &&
 	 git branch -r > output &&
-	 test_cmp ../expect output)
+	 test_cmp ../expect output &&
+	 grep "built-in: git gc" trace >gc &&
+	 test_line_count = 1 gc
+	)
 '
 
 test_expect_success 'git fetch --multiple (bad remote names)' '
-- 
2.22.0.rc0.322.g2b0371e29a


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Thread overview: 61+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2019-06-19  9:46 [PATCH] fetch: only run 'gc' once when fetching multiple remotes Nguyễn Thái Ngọc Duy
2019-06-19 10:26 ` [RFC/PATCH] gc: run more pre-detach operations under lock Ævar Arnfjörð Bjarmason
2019-06-19 12:51   ` Duy Nguyen
2019-06-19 18:01     ` Ævar Arnfjörð Bjarmason
2019-06-19 19:10       ` Jeff King
2019-06-19 22:49         ` Ævar Arnfjörð Bjarmason
2019-06-19 23:30           ` [PATCH 0/6] Change <non-empty?> GIT_TEST_* variables to <boolean> Ævar Arnfjörð Bjarmason
2019-06-20 18:13             ` Junio C Hamano
2019-06-20 21:00               ` Ævar Arnfjörð Bjarmason
2019-06-20 20:03             ` Junio C Hamano
2019-06-20 21:09             ` [PATCH v2 0/8] " Ævar Arnfjörð Bjarmason
2019-06-21 10:18               ` [PATCH v3 " Ævar Arnfjörð Bjarmason
2019-06-21 10:18               ` [PATCH v3 1/8] config tests: simplify include cycle test Ævar Arnfjörð Bjarmason
2019-06-21 10:18               ` [PATCH v3 2/8] env--helper: new undocumented builtin wrapping git_env_*() Ævar Arnfjörð Bjarmason
2019-06-21 17:07                 ` Junio C Hamano
2019-06-21 10:18               ` [PATCH v3 3/8] config.c: refactor die_bad_number() to not call gettext() early Ævar Arnfjörð Bjarmason
2019-06-21 10:18               ` [PATCH v3 4/8] t6040 test: stop using global "script" variable Ævar Arnfjörð Bjarmason
2019-06-21 10:18               ` [PATCH v3 5/8] tests: make GIT_TEST_GETTEXT_POISON a boolean Ævar Arnfjörð Bjarmason
2019-06-24 16:47                 ` Junio C Hamano
2019-06-21 10:18               ` [PATCH v3 6/8] tests README: re-flow a previously changed paragraph Ævar Arnfjörð Bjarmason
2019-06-21 10:18               ` [PATCH v3 7/8] tests: replace test_tristate with "git env--helper" Ævar Arnfjörð Bjarmason
2019-09-06 12:13                 ` [PATCH 1/2] t/lib-git-svn.sh: check GIT_TEST_SVN_HTTPD when running SVN HTTP tests SZEDER Gábor
2019-09-06 12:13                   ` [PATCH 2/2] ci: restore running httpd tests SZEDER Gábor
2019-09-06 17:03                     ` Junio C Hamano
2019-09-06 19:13                     ` Jeff King
2019-09-07 10:16                       ` SZEDER Gábor
2019-11-22 13:14                         ` [PATCH 0/2] tests: catch non-bool GIT_TEST_* values SZEDER Gábor
2019-11-22 13:14                           ` [PATCH 1/2] tests: add 'test_bool_env' to " SZEDER Gábor
2019-11-25 13:50                             ` Jeff King
2019-11-22 13:14                           ` [PATCH 2/2] t5608-clone-2gb.sh: turn GIT_TEST_CLONE_2GB into a bool SZEDER Gábor
2019-11-25 13:53                             ` Jeff King
2019-06-21 10:18               ` [PATCH v3 8/8] tests: make GIT_TEST_FAIL_PREREQS a boolean Ævar Arnfjörð Bjarmason
2019-06-20 21:09             ` [PATCH v2 1/8] config tests: simplify include cycle test Ævar Arnfjörð Bjarmason
2019-06-20 21:09             ` [PATCH v2 2/8] env--helper: new undocumented builtin wrapping git_env_*() Ævar Arnfjörð Bjarmason
2019-06-20 22:11               ` Junio C Hamano
2019-06-20 22:21                 ` Junio C Hamano
2019-06-21  8:11                   ` Ævar Arnfjörð Bjarmason
2019-06-21 15:04                     ` Junio C Hamano
2019-06-20 21:09             ` [PATCH v2 3/8] config.c: refactor die_bad_number() to not call gettext() early Ævar Arnfjörð Bjarmason
2019-06-20 21:09             ` [PATCH v2 4/8] t6040 test: stop using global "script" variable Ævar Arnfjörð Bjarmason
2019-06-20 21:09             ` [PATCH v2 5/8] tests: make GIT_TEST_GETTEXT_POISON a boolean Ævar Arnfjörð Bjarmason
2019-06-20 21:09             ` [PATCH v2 6/8] tests README: re-flow a previously changed paragraph Ævar Arnfjörð Bjarmason
2019-06-20 21:09             ` [PATCH v2 7/8] tests: replace test_tristate with "git env--helper" Ævar Arnfjörð Bjarmason
2019-06-20 21:09             ` [PATCH v2 8/8] tests: make GIT_TEST_FAIL_PREREQS a boolean Ævar Arnfjörð Bjarmason
2019-06-19 23:30           ` [PATCH 1/6] env--helper: new undocumented builtin wrapping git_env_*() Ævar Arnfjörð Bjarmason
2019-06-20 19:25             ` Junio C Hamano
2019-06-19 23:30           ` [PATCH 2/6] t6040 test: stop using global "script" variable Ævar Arnfjörð Bjarmason
2019-06-20 19:54             ` Junio C Hamano
2019-06-19 23:30           ` [PATCH 3/6] tests: make GIT_TEST_GETTEXT_POISON a boolean Ævar Arnfjörð Bjarmason
2019-06-20 20:00             ` Junio C Hamano
2019-06-19 23:30           ` [PATCH 4/6] tests README: re-flow a previously changed paragraph Ævar Arnfjörð Bjarmason
2019-06-19 23:30           ` [PATCH 5/6] tests: replace test_tristate with "git env--helper" Ævar Arnfjörð Bjarmason
2019-06-19 23:30           ` [PATCH 6/6] tests: make GIT_TEST_FAIL_PREREQS a boolean Ævar Arnfjörð Bjarmason
2019-06-20 10:26           ` [RFC/PATCH] gc: run more pre-detach operations under lock Duy Nguyen
2019-06-20 21:49             ` Ævar Arnfjörð Bjarmason
2019-06-20 10:43           ` Jeff King
2019-06-20 18:55         ` Junio C Hamano
2019-06-19 19:08     ` Jeff King
2019-06-19 18:59 ` [PATCH] fetch: only run 'gc' once when fetching multiple remotes Jeff King
2019-06-20 10:11   ` Duy Nguyen
2019-06-20 10:21     ` Jeff King

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