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[PATCH 19/24] update-index: manually enable or disable untracked cache

From
Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
Date
Mar 8, 2015, 10:12 UTC
Message-ID
<1425809567-25518-20-git-send-email-pclouds@gmail.com>
In-Reply-To
<1425809567-25518-1-git-send-email-pclouds@gmail.com>

Overall time saving on "git status" is about 40% in the best case scenario, removing ..collect_untracked() as the most time consuming function. read and refresh index operations are now at the top (which should drop when index-helper and/or watchman support is added). More numbers and analysis below.

webkit.git ==========

169k files. 6k dirs. Lots of test data (i.e. not touched most of the time)

Base status -----------

Index version 4 in split index mode and cache-tree populated. No untracked cache. It shows how time is consumed by "git status". The same settings are used for other repos below.

18:28:10.199679 builtin/commit.c:1394 performance: 0.000000451 s: cmd_status:setup 18:28:10.474847 read-cache.c:1407 performance: 0.274873831 s: read_index 18:28:10.475295 read-cache.c:1407 performance: 0.000000656 s: read_index 18:28:10.728443 preload-index.c:131 performance: 0.253147487 s: read_index_preload 18:28:10.741422 read-cache.c:1254 performance: 0.012868340 s: refresh_index 18:28:10.752300 wt-status.c:623 performance: 0.010421357 s: wt_status_collect_changes_worktree 18:28:10.762069 wt-status.c:629 performance: 0.009644748 s: wt_status_collect_changes_index 18:28:11.601019 wt-status.c:632 performance: 0.838859547 s: wt_status_collect_untracked 18:28:11.605939 builtin/commit.c:1421 performance: 0.004835004 s: cmd_status:update_index 18:28:11.606580 trace.c:415 performance: 1.407878388 s: git command: 'git' 'status'

Populating status -----------------

This is after enabling untracked cache and the cache is still empty. We see a slight increase in .._collect_untracked() and update_index (because new cache has to be written to $GIT_DIR/index).

18:28:18.915213 builtin/commit.c:1394 performance: 0.000000326 s: cmd_status:setup 18:28:19.197364 read-cache.c:1407 performance: 0.281901416 s: read_index 18:28:19.197754 read-cache.c:1407 performance: 0.000000546 s: read_index 18:28:19.451355 preload-index.c:131 performance: 0.253599607 s: read_index_preload 18:28:19.464400 read-cache.c:1254 performance: 0.012935336 s: refresh_index 18:28:19.475115 wt-status.c:623 performance: 0.010236920 s: wt_status_collect_changes_worktree 18:28:19.486022 wt-status.c:629 performance: 0.010801685 s: wt_status_collect_changes_index 18:28:20.362660 wt-status.c:632 performance: 0.876551366 s: wt_status_collect_untracked 18:28:20.396199 builtin/commit.c:1421 performance: 0.033447969 s: cmd_status:update_index 18:28:20.396939 trace.c:415 performance: 1.482695902 s: git command: 'git' 'status'

Populated status ----------------

After the cache is populated, wt_status_collect_untracked() drops 82% from 0.838s to 0.144s. Overall time drops 45%. Top offenders are now read_index() and read_index_preload().

18:28:20.408605 builtin/commit.c:1394 performance: 0.000000457 s: cmd_status:setup 18:28:20.692864 read-cache.c:1407 performance: 0.283980458 s: read_index 18:28:20.693273 read-cache.c:1407 performance: 0.000000661 s: read_index 18:28:20.958814 preload-index.c:131 performance: 0.265540254 s: read_index_preload 18:28:20.972375 read-cache.c:1254 performance: 0.013437429 s: refresh_index 18:28:20.983959 wt-status.c:623 performance: 0.011146646 s: wt_status_collect_changes_worktree 18:28:20.993948 wt-status.c:629 performance: 0.009879094 s: wt_status_collect_changes_index 18:28:21.138125 wt-status.c:632 performance: 0.144084737 s: wt_status_collect_untracked 18:28:21.173678 builtin/commit.c:1421 performance: 0.035463949 s: cmd_status:update_index 18:28:21.174251 trace.c:415 performance: 0.766707355 s: git command: 'git' 'status'

gentoo-x86.git ==============

This repository is a strange one with a balanced, wide and shallow worktree (about 100k files and 23k dirs) and no .gitignore in worktree. .._collect_untracked() time drops 88%, total time drops 56%.

Base status ----------- 18:20:40.828642 builtin/commit.c:1394 performance: 0.000000496 s: cmd_status:setup 18:20:41.027233 read-cache.c:1407 performance: 0.198130532 s: read_index 18:20:41.027670 read-cache.c:1407 performance: 0.000000581 s: read_index 18:20:41.171716 preload-index.c:131 performance: 0.144045594 s: read_index_preload 18:20:41.179171 read-cache.c:1254 performance: 0.007320424 s: refresh_index 18:20:41.185785 wt-status.c:623 performance: 0.006144638 s: wt_status_collect_changes_worktree 18:20:41.192701 wt-status.c:629 performance: 0.006780184 s: wt_status_collect_changes_index 18:20:41.991723 wt-status.c:632 performance: 0.798927029 s: wt_status_collect_untracked 18:20:41.994664 builtin/commit.c:1421 performance: 0.002852772 s: cmd_status:update_index 18:20:41.995458 trace.c:415 performance: 1.168427502 s: git command: 'git' 'status' Populating status ----------------- 18:20:48.968848 builtin/commit.c:1394 performance: 0.000000380 s: cmd_status:setup 18:20:49.172918 read-cache.c:1407 performance: 0.203734214 s: read_index 18:20:49.173341 read-cache.c:1407 performance: 0.000000562 s: read_index 18:20:49.320013 preload-index.c:131 performance: 0.146671391 s: read_index_preload 18:20:49.328039 read-cache.c:1254 performance: 0.007921957 s: refresh_index 18:20:49.334680 wt-status.c:623 performance: 0.006172020 s: wt_status_collect_changes_worktree 18:20:49.342526 wt-status.c:629 performance: 0.007731746 s: wt_status_collect_changes_index 18:20:50.257510 wt-status.c:632 performance: 0.914864222 s: wt_status_collect_untracked 18:20:50.338371 builtin/commit.c:1421 performance: 0.080776477 s: cmd_status:update_index 18:20:50.338900 trace.c:415 performance: 1.371462446 s: git command: 'git' 'status' Populated status ---------------- 18:20:50.351160 builtin/commit.c:1394 performance: 0.000000571 s: cmd_status:setup 18:20:50.577358 read-cache.c:1407 performance: 0.225917338 s: read_index 18:20:50.577794 read-cache.c:1407 performance: 0.000000617 s: read_index 18:20:50.734140 preload-index.c:131 performance: 0.156345564 s: read_index_preload 18:20:50.745717 read-cache.c:1254 performance: 0.011463075 s: refresh_index 18:20:50.755176 wt-status.c:623 performance: 0.008877929 s: wt_status_collect_changes_worktree 18:20:50.763768 wt-status.c:629 performance: 0.008471633 s: wt_status_collect_changes_index 18:20:50.854885 wt-status.c:632 performance: 0.090988721 s: wt_status_collect_untracked 18:20:50.857765 builtin/commit.c:1421 performance: 0.002789097 s: cmd_status:update_index 18:20:50.858411 trace.c:415 performance: 0.508647673 s: git command: 'git' 'status'

linux-2.6 =========

Reference repo. Not too big. .._collect_status() drops 84%. Total time drops 42%.

Base status ----------- 18:34:09.870122 builtin/commit.c:1394 performance: 0.000000385 s: cmd_status:setup 18:34:09.943218 read-cache.c:1407 performance: 0.072871177 s: read_index 18:34:09.943614 read-cache.c:1407 performance: 0.000000491 s: read_index 18:34:10.004364 preload-index.c:131 performance: 0.060748102 s: read_index_preload 18:34:10.008190 read-cache.c:1254 performance: 0.003714285 s: refresh_index 18:34:10.012087 wt-status.c:623 performance: 0.002775446 s: wt_status_collect_changes_worktree 18:34:10.016054 wt-status.c:629 performance: 0.003862140 s: wt_status_collect_changes_index 18:34:10.214747 wt-status.c:632 performance: 0.198604837 s: wt_status_collect_untracked 18:34:10.216102 builtin/commit.c:1421 performance: 0.001244166 s: cmd_status:update_index 18:34:10.216817 trace.c:415 performance: 0.347670735 s: git command: 'git' 'status' Populating status ----------------- 18:34:16.595102 builtin/commit.c:1394 performance: 0.000000456 s: cmd_status:setup 18:34:16.666600 read-cache.c:1407 performance: 0.070992413 s: read_index 18:34:16.667012 read-cache.c:1407 performance: 0.000000606 s: read_index 18:34:16.729375 preload-index.c:131 performance: 0.062362492 s: read_index_preload 18:34:16.732565 read-cache.c:1254 performance: 0.003075517 s: refresh_index 18:34:16.736148 wt-status.c:623 performance: 0.002422201 s: wt_status_collect_changes_worktree 18:34:16.739990 wt-status.c:629 performance: 0.003746618 s: wt_status_collect_changes_index 18:34:16.948505 wt-status.c:632 performance: 0.208426710 s: wt_status_collect_untracked 18:34:16.961744 builtin/commit.c:1421 performance: 0.013151887 s: cmd_status:update_index 18:34:16.962233 trace.c:415 performance: 0.368537535 s: git command: 'git' 'status' Populated status ---------------- 18:34:16.970026 builtin/commit.c:1394 performance: 0.000000631 s: cmd_status:setup 18:34:17.046235 read-cache.c:1407 performance: 0.075904673 s: read_index 18:34:17.046644 read-cache.c:1407 performance: 0.000000681 s: read_index 18:34:17.113564 preload-index.c:131 performance: 0.066920253 s: read_index_preload 18:34:17.117281 read-cache.c:1254 performance: 0.003604055 s: refresh_index 18:34:17.121115 wt-status.c:623 performance: 0.002508345 s: wt_status_collect_changes_worktree 18:34:17.125089 wt-status.c:629 performance: 0.003871636 s: wt_status_collect_changes_index 18:34:17.156089 wt-status.c:632 performance: 0.030895703 s: wt_status_collect_untracked 18:34:17.169861 builtin/commit.c:1421 performance: 0.013686404 s: cmd_status:update_index 18:34:17.170391 trace.c:415 performance: 0.201474531 s: git command: 'git' 'status'

Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
---
 Documentation/git-update-index.txt |  8 ++++++++
 builtin/update-index.c             | 16 ++++++++++++++++
 2 files changed, 24 insertions(+)
diff --git a/Documentation/git-update-index.txt b/Documentation/git-update-index.txt
index dfc09d9..f9a35cd 100644
--- a/Documentation/git-update-index.txt
+++ b/Documentation/git-update-index.txt
@@ -172,6 +172,14 @@ may not support it yet.
 	the shared index file. This mode is designed for very large
 	indexes that take a signficant amount of time to read or write.
 
+--untracked-cache::
+--no-untracked-cache::
+	Enable or disable untracked cache extension. This could speed
+	up for commands that involve determining untracked files such
+	as `git status`. The underlying operating system and file
+	system must change `st_mtime` field of a directory if files
+	are added or deleted in that directory.
+
 \--::
 	Do not interpret any more arguments as options.
 
diff --git a/builtin/update-index.c b/builtin/update-index.c
index e8c7fd4..3d2dedd 100644
--- a/builtin/update-index.c
+++ b/builtin/update-index.c
@@ -740,6 +740,7 @@ static int reupdate_callback(struct parse_opt_ctx_t *ctx,
 int cmd_update_index(int argc, const char **argv, const char *prefix)
 {
 	int newfd, entries, has_errors = 0, line_termination = '\n';
+	int untracked_cache = -1;
 	int read_from_stdin = 0;
 	int prefix_length = prefix ? strlen(prefix) : 0;
 	int preferred_index_format = 0;
@@ -831,6 +832,8 @@ int cmd_update_index(int argc, const char **argv, const char *prefix)
 			N_("write index in this format")),
 		OPT_BOOL(0, "split-index", &split_index,
 			N_("enable or disable split index")),
+		OPT_BOOL(0, "untracked-cache", &untracked_cache,
+			N_("enable/disable untracked cache")),
 		OPT_END()
 	};
 
@@ -937,6 +940,19 @@ int cmd_update_index(int argc, const char **argv, const char *prefix)
 		the_index.split_index = NULL;
 		the_index.cache_changed |= SOMETHING_CHANGED;
 	}
+	if (untracked_cache > 0 && !the_index.untracked) {
+		struct untracked_cache *uc;
+
+		uc = xcalloc(1, sizeof(*uc));
+		uc->exclude_per_dir = ".gitignore";
+		/* should be the same flags used by git-status */
+		uc->dir_flags = DIR_SHOW_OTHER_DIRECTORIES | DIR_HIDE_EMPTY_DIRECTORIES;
+		the_index.untracked = uc;
+		the_index.cache_changed |= UNTRACKED_CHANGED;
+	} else if (!untracked_cache && the_index.untracked) {
+		the_index.untracked = NULL;
+		the_index.cache_changed |= UNTRACKED_CHANGED;
+	}
 
 	if (active_cache_changed) {
 		if (newfd < 0) {

-- 
2.3.0.rc1.137.g477eb31
Previous: Nguyễn Thái Ngọc DuyNext: Nguyễn Thái Ngọc Duy
Message 20 of 25 in “nd/untracked-cache updates”
  1. 00/24 nd/untracked-cache updatesNguyễn Thái Ngọc Duy, Mar 8, 2015
  2. 01/24 dir.c: optionally compute sha-1 of a .gitignore fileNguyễn Thái Ngọc Duy, Mar 8, 2015
  3. 02/24 untracked cache: record .gitignore information and dir hierarchyNguyễn Thái Ngọc Duy, Mar 8, 2015
  4. 03/24 untracked cache: initial untracked cache validationNguyễn Thái Ngọc Duy, Mar 8, 2015
  5. 04/24 untracked cache: invalidate dirs recursively if .gitignore changesNguyễn Thái Ngọc Duy, Mar 8, 2015
  6. 05/24 untracked cache: make a wrapper around {open,read,close}dir()Nguyễn Thái Ngọc Duy, Mar 8, 2015
  7. 06/24 untracked cache: record/validate dir mtime and reuse cached outputNguyễn Thái Ngọc Duy, Mar 8, 2015
  8. 07/24 untracked cache: mark what dirs should be recursed/savedNguyễn Thái Ngọc Duy, Mar 8, 2015
  9. 08/24 untracked cache: don't open non-existent .gitignoreNguyễn Thái Ngọc Duy, Mar 8, 2015
  10. 09/24 ewah: add convenient wrapper ewah_serialize_strbuf()Nguyễn Thái Ngọc Duy, Mar 8, 2015
  11. 10/24 untracked cache: save to an index extensionNguyễn Thái Ngọc Duy, Mar 8, 2015
  12. 11/24 untracked cache: load from UNTR index extensionNguyễn Thái Ngọc Duy, Mar 8, 2015
  13. 12/24 untracked cache: invalidate at index addition or removalNguyễn Thái Ngọc Duy, Mar 8, 2015
  14. 13/24 read-cache.c: split racy stat test to a separate functionNguyễn Thái Ngọc Duy, Mar 8, 2015
  15. 14/24 untracked cache: avoid racy timestampsNguyễn Thái Ngọc Duy, Mar 8, 2015
  16. 15/24 untracked cache: print stats with $GIT_TRACE_UNTRACKED_STATSNguyễn Thái Ngọc Duy, Mar 8, 2015
  17. 16/24 untracked cache: mark index dirty if untracked cache is updatedNguyễn Thái Ngọc Duy, Mar 8, 2015
  18. 17/24 untracked-cache: temporarily disable with $GIT_DISABLE_UNTRACKED_CACHENguyễn Thái Ngọc Duy, Mar 8, 2015
  19. 18/24 status: enable untracked cacheNguyễn Thái Ngọc Duy, Mar 8, 2015
  20. 19/24 update-index: manually enable or disable untracked cacheNguyễn Thái Ngọc Duy, Mar 8, 2015
  21. 20/24 update-index: test the system before enabling untracked cacheNguyễn Thái Ngọc Duy, Mar 8, 2015
  22. 21/24 t7063: tests for untracked cacheNguyễn Thái Ngọc Duy, Mar 8, 2015
  23. 22/24 mingw32: add uname()Nguyễn Thái Ngọc Duy, Mar 8, 2015
  24. 23/24 untracked cache: guard and disable on system changesNguyễn Thái Ngọc Duy, Mar 8, 2015
  25. 24/24 git-status.txt: advertisement for untracked cacheNguyễn Thái Ngọc Duy, Mar 8, 2015

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