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[PATCH v13 19/20] trace: measure where the time is spent in the index-heavy operations

From
David Turner <novalis@novalis.org>
Date
Jun 26, 2016, 04:14 UTC
Message-ID
<1466914464-10358-19-git-send-email-novalis@novalis.org>
In-Reply-To
<1466914464-10358-1-git-send-email-novalis@novalis.org>
From: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>

All the known heavy code blocks are measured (except object database access). This should help identify if an optimization is effective or not. An unoptimized git-status would give something like below (92% of time is accounted). To sum up the effort of making git scale better:

 - read cache line is being addressed by index-helper
 - preload/refresh index by watchman
 - read packed refs by lmdb backend
 - diff-index by rebuilding cache-tree
 - read directory by untracked cache and watchman
 - write index by split index
 - name hash potientially by index-helper

read-cache.c:2075 performance: 0.004058570 s: read cache .../index preload-index.c:104 performance: 0.004419864 s: preload index read-cache.c:1265 performance: 0.000185224 s: refresh index refs/files-backend.c:1100 performance: 0.001935788 s: read packed refs diff-lib.c:240 performance: 0.000144132 s: diff-files diff-lib.c:506 performance: 0.013592000 s: diff-index name-hash.c:128 performance: 0.000614177 s: initialize name hash dir.c:2030 performance: 0.015814103 s: read directory read-cache.c:2565 performance: 0.004052343 s: write index, changed mask = 2 trace.c:420 performance: 0.048365509 s: git command: './git' 'status'

Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
Signed-off-by: David Turner <dturner@twopensource.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
---
 diff-lib.c           |  4 ++++
 dir.c                |  2 ++
 name-hash.c          |  2 ++
 preload-index.c      |  2 ++
 read-cache.c         | 11 +++++++++++
 refs/files-backend.c |  2 ++
 6 files changed, 23 insertions(+)
diff --git a/diff-lib.c b/diff-lib.c
index bc49c70..7af7f9a 100644
--- a/diff-lib.c
+++ b/diff-lib.c
@@ -90,6 +90,7 @@ int run_diff_files(struct rev_info *revs, unsigned int option)
 	int diff_unmerged_stage = revs->max_count;
 	unsigned ce_option = ((option & DIFF_RACY_IS_MODIFIED)
 			      ? CE_MATCH_RACY_IS_DIRTY : 0);
+	uint64_t start = getnanotime();
 
 	diff_set_mnemonic_prefix(&revs->diffopt, "i/", "w/");
 
@@ -236,6 +237,7 @@ int run_diff_files(struct rev_info *revs, unsigned int option)
 	}
 	diffcore_std(&revs->diffopt);
 	diff_flush(&revs->diffopt);
+	trace_performance_since(start, "diff-files");
 	return 0;
 }
 
@@ -491,6 +493,7 @@ static int diff_cache(struct rev_info *revs,
 int run_diff_index(struct rev_info *revs, int cached)
 {
 	struct object_array_entry *ent;
+	uint64_t start = getnanotime();
 
 	ent = revs->pending.objects;
 	if (diff_cache(revs, ent->item->oid.hash, ent->name, cached))
@@ -500,6 +503,7 @@ int run_diff_index(struct rev_info *revs, int cached)
 	diffcore_fix_diff_index(&revs->diffopt);
 	diffcore_std(&revs->diffopt);
 	diff_flush(&revs->diffopt);
+	trace_performance_since(start, "diff-index");
 	return 0;
 }
 
diff --git a/dir.c b/dir.c
index 850d4fb..024b13c 100644
--- a/dir.c
+++ b/dir.c
@@ -1991,6 +1991,7 @@ int read_directory(struct dir_struct *dir, const char *path, int len, const stru
 {
 	struct path_simplify *simplify;
 	struct untracked_cache_dir *untracked;
+	uint64_t start = getnanotime();
 
 	/*
 	 * Check out create_simplify()
@@ -2026,6 +2027,7 @@ int read_directory(struct dir_struct *dir, const char *path, int len, const stru
 	free_simplify(simplify);
 	qsort(dir->entries, dir->nr, sizeof(struct dir_entry *), cmp_name);
 	qsort(dir->ignored, dir->ignored_nr, sizeof(struct dir_entry *), cmp_name);
+	trace_performance_since(start, "read directory %.*s", len, path);
 	if (dir->untracked) {
 		static struct trace_key trace_untracked_stats = TRACE_KEY_INIT(UNTRACKED_STATS);
 		trace_printf_key(&trace_untracked_stats,
diff --git a/name-hash.c b/name-hash.c
index 6d9f23e..b3966d8 100644
--- a/name-hash.c
+++ b/name-hash.c
@@ -115,6 +115,7 @@ static int cache_entry_cmp(const struct cache_entry *ce1,
 static void lazy_init_name_hash(struct index_state *istate)
 {
 	int nr;
+	uint64_t start = getnanotime();
 
 	if (istate->name_hash_initialized)
 		return;
@@ -124,6 +125,7 @@ static void lazy_init_name_hash(struct index_state *istate)
 	for (nr = 0; nr < istate->cache_nr; nr++)
 		hash_index_entry(istate, istate->cache[nr]);
 	istate->name_hash_initialized = 1;
+	trace_performance_since(start, "initialize name hash");
 }
 
 void add_name_hash(struct index_state *istate, struct cache_entry *ce)
diff --git a/preload-index.c b/preload-index.c
index c1fe3a3..7bb4809 100644
--- a/preload-index.c
+++ b/preload-index.c
@@ -72,6 +72,7 @@ static void preload_index(struct index_state *index,
 {
 	int threads, i, work, offset;
 	struct thread_data data[MAX_PARALLEL];
+	uint64_t start = getnanotime();
 
 	if (!core_preload_index)
 		return;
@@ -100,6 +101,7 @@ static void preload_index(struct index_state *index,
 		if (pthread_join(p->pthread, NULL))
 			die("unable to join threaded lstat");
 	}
+	trace_performance_since(start, "preload index");
 }
 #endif
 
diff --git a/read-cache.c b/read-cache.c
index fde778b..ee777c1 100644
--- a/read-cache.c
+++ b/read-cache.c
@@ -1189,6 +1189,7 @@ int refresh_index(struct index_state *istate, unsigned int flags,
 	const char *typechange_fmt;
 	const char *added_fmt;
 	const char *unmerged_fmt;
+	uint64_t start = getnanotime();
 
 	modified_fmt = (in_porcelain ? "M\t%s\n" : "%s: needs update\n");
 	deleted_fmt = (in_porcelain ? "D\t%s\n" : "%s: needs update\n");
@@ -1273,6 +1274,7 @@ int refresh_index(struct index_state *istate, unsigned int flags,
 
 		replace_index_entry(istate, i, new);
 	}
+	trace_performance_since(start, "refresh index");
 	return has_errors;
 }
 
@@ -2092,12 +2094,15 @@ int read_index_from(struct index_state *istate, const char *path)
 {
 	struct split_index *split_index;
 	int ret;
+	uint64_t start;
 
 	/* istate->initialized covers both .git/index and .git/sharedindex.xxx */
 	if (istate->initialized)
 		return istate->cache_nr;
 
+	start = getnanotime();
 	ret = do_read_index(istate, path, 0);
+	trace_performance_since(start, "read cache %s", path);
 
 	split_index = istate->split_index;
 	if (!split_index || is_null_sha1(split_index->base_sha1)) {
@@ -2112,6 +2117,7 @@ int read_index_from(struct index_state *istate, const char *path)
 	split_index->base->keep_mmap = istate->keep_mmap;
 	split_index->base->to_shm    = istate->to_shm;
 	split_index->base->from_shm  = istate->from_shm;
+	start = getnanotime();
 	ret = do_read_index(split_index->base,
 			    git_path("sharedindex.%s",
 				     sha1_to_hex(split_index->base_sha1)), 1);
@@ -2123,6 +2129,9 @@ int read_index_from(struct index_state *istate, const char *path)
 		    sha1_to_hex(split_index->base->sha1));
 	merge_base_index(istate);
 	post_read_index_from(istate);
+	trace_performance_since(start, "read cache %s",
+				git_path("sharedindex.%s",
+					 sha1_to_hex(split_index->base_sha1)));
 
 done:
 	if (ret > 0 && istate->from_shm && istate->last_update)
@@ -2468,6 +2477,7 @@ static int do_write_index(struct index_state *istate, int newfd,
 	struct stat st;
 	struct strbuf previous_name_buf = STRBUF_INIT, *previous_name;
 	int watchman = 0;
+	uint64_t start = getnanotime();
 
 	for (i = removed = extended = 0; i < entries; i++) {
 		if (cache[i]->ce_flags & CE_REMOVE)
@@ -2588,6 +2598,7 @@ static int do_write_index(struct index_state *istate, int newfd,
 		return -1;
 	istate->timestamp.sec = (unsigned int)st.st_mtime;
 	istate->timestamp.nsec = ST_MTIME_NSEC(st);
+	trace_performance_since(start, "write index, changed mask = %x", istate->cache_changed);
 	return 0;
 }
 
diff --git a/refs/files-backend.c b/refs/files-backend.c
index 81f68f8..57571ce 100644
--- a/refs/files-backend.c
+++ b/refs/files-backend.c
@@ -1048,6 +1048,7 @@ static void read_packed_refs(FILE *f, struct ref_dir *dir)
 	struct ref_entry *last = NULL;
 	struct strbuf line = STRBUF_INIT;
 	enum { PEELED_NONE, PEELED_TAGS, PEELED_FULLY } peeled = PEELED_NONE;
+	uint64_t start = getnanotime();
 
 	while (strbuf_getwholeline(&line, f, '\n') != EOF) {
 		unsigned char sha1[20];
@@ -1096,6 +1097,7 @@ static void read_packed_refs(FILE *f, struct ref_dir *dir)
 	}
 
 	strbuf_release(&line);
+	trace_performance_since(start, "read packed refs");
 }
 
 /*

-- 
1.9.1
Previous: David TurnerNext: Nguyễn Thái Ngọc Duy
Message 30 of 35 in “read-cache.c: fix constness of verify_hdr()”
  1. 01/20 read-cache.c: fix constness of verify_hdr()David Turner, Jun 26, 2016
  2. 04/20 index-helper: new daemon for caching index and related stuffDavid Turner, Jun 26, 2016
  3. Johannes SchindelinJun 30, 2016
  4. Duy NguyenJun 30, 2016
  5. Johannes SchindelinJul 2, 2016
  6. Duy NguyenJul 2, 2016
  7. 03/20 pkt-line: add gentle version of packet_writeDavid Turner, Jun 26, 2016
  8. 02/20 read-cache: allow to keep mmap'd memory after readingDavid Turner, Jun 26, 2016
  9. 06/20 daemonize(): set a flag before exiting the main processDavid Turner, Jun 26, 2016
  10. 05/20 index-helper: add --strictDavid Turner, Jun 26, 2016
  11. 18/20 index-helper: optionally automatically runDavid Turner, Jun 26, 2016
  12. 17/20 index-helper: autorun modeDavid Turner, Jun 26, 2016
  13. 15/20 index-helper: kill modeDavid Turner, Jun 26, 2016
  14. 14/20 watchman: add a config option to enable the extensionDavid Turner, Jun 26, 2016
  15. 13/20 unpack-trees: preserve index extensionsDavid Turner, Jun 26, 2016
  16. 16/20 index-helper: don't run if already runningDavid Turner, Jun 26, 2016
  17. 12/20 update-index: enable/disable watchman supportDavid Turner, Jun 26, 2016
  18. 09/20 read-cache: add watchman 'WAMA' extensionDavid Turner, Jun 26, 2016
  19. 10/20 watchman: support watchman to reduce index refresh costDavid Turner, Jun 26, 2016
  20. 11/20 index-helper: use watchman to avoid refreshing index with lstat()David Turner, Jun 26, 2016
  21. Ben PeartJun 30, 2016
  22. Duy NguyenJun 30, 2016
  23. Ben PeartJun 30, 2016
  24. Duy NguyenJul 3, 2016
  25. Ben PeartJul 6, 2016
  26. Duy NguyenJul 8, 2016
  27. Duy NguyenJul 8, 2016
  28. 07/20 index-helper: add --detachDavid Turner, Jun 26, 2016
  29. 08/20 index-helper: log warningsDavid Turner, Jun 26, 2016
  30. 19/20 trace: measure where the time is spent in the index-heavy operationsDavid Turner, Jun 26, 2016
  31. 21/20 unix-socket.c: add stub implementation when unix sockets are not supportedNguyễn Thái Ngọc Duy, Jun 26, 2016
  32. Johannes SchindelinJun 27, 2016
  33. Duy NguyenJun 27, 2016
  34. Johannes SchindelinJun 28, 2016
  35. David TurnerJun 27, 2016

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