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[PATCH v2 12/21] bisect: replace clear_distance() by unique markers

From
Stephan Beyer <s-beyer@gmx.net>
Date
Apr 10, 2016, 13:19 UTC
Message-ID
<1460294354-7031-13-git-send-email-s-beyer@gmx.net>
In-Reply-To
<1460294354-7031-1-git-send-email-s-beyer@gmx.net>

clear_distance() was a O(#commits)-time function to clear the COUNTED flag from commits counted in count_distance(). The functions count_distance() and clear_distance() were called for each merge commit.

This commit gets rid of the clear_distance() function by making count_distance() use unique marker ids that do not need to be cleared afterwards. This speeds up the bisecting process on large repositories with a huge amount of merges.

Signed-off-by: Stephan Beyer <s-beyer@gmx.net>
---
 bisect.c | 29 +++++++++++------------------
 1 file changed, 11 insertions(+), 18 deletions(-)
diff --git a/bisect.c b/bisect.c
index bc1bfbd..4209c75 100644
--- a/bisect.c
+++ b/bisect.c
@@ -23,13 +23,13 @@ static const char *argv_show_branch[] = {"show-branch", NULL, NULL};
 static const char *term_bad;
 static const char *term_good;
 
+static unsigned marker;
+
 struct node_data {
 	int weight;
+	unsigned marked;
 };
 
-/* Remember to update object flag allocation in object.h */
-#define COUNTED		(1u<<16)
-
 #define DEBUG_BISECT 0
 
 static inline struct node_data *node_data(struct commit *elem)
@@ -43,15 +43,17 @@ static int count_distance(struct commit_list *entry)
 	int nr = 0;
 	struct commit_list *todo = NULL;
 	commit_list_append(entry->item, &todo);
+	marker++;
 
 	while (todo) {
 		struct commit *commit = pop_commit(&todo);
 
-		if (!(commit->object.flags & (UNINTERESTING | COUNTED))) {
+		if (!(commit->object.flags & UNINTERESTING)
+		 && node_data(commit)->marked != marker) {
 			struct commit_list *p;
 			if (!(commit->object.flags & TREESAME))
 				nr++;
-			commit->object.flags |= COUNTED;
+			node_data(commit)->marked = marker;
 
 			for (p = commit->parents; p; p = p->next) {
 				commit_list_insert(p->item, &todo);
@@ -62,15 +64,6 @@ static int count_distance(struct commit_list *entry)
 	return nr;
 }
 
-static void clear_distance(struct commit_list *list)
-{
-	while (list) {
-		struct commit *commit = list->item;
-		commit->object.flags &= ~COUNTED;
-		list = list->next;
-	}
-}
-
 static int count_interesting_parents(struct commit *commit)
 {
 	struct commit_list *p;
@@ -123,10 +116,9 @@ static void show_list(const char *debug, int counted, int nr,
 		const char *subject_start;
 		int subject_len;
 
-		fprintf(stderr, "%c%c%c ",
+		fprintf(stderr, "%c%c ",
 			(flags & TREESAME) ? ' ' : 'T',
-			(flags & UNINTERESTING) ? 'U' : ' ',
-			(flags & COUNTED) ? 'C' : ' ');
+			(flags & UNINTERESTING) ? 'U' : ' ');
 		if (commit->util)
 			fprintf(stderr, "%3d", node_data(commit)->weight);
 		else
@@ -289,7 +281,6 @@ static struct commit_list *do_find_bisection(struct commit_list *list,
 		if (!(p->item->object.flags & UNINTERESTING)
 		 && (node_data(p->item)->weight == -2)) {
 			node_data(p->item)->weight = count_distance(p);
-			clear_distance(list);
 
 			/* Does it happen to be at exactly half-way? */
 			if (!find_all && halfway(p, nr))
@@ -351,6 +342,8 @@ struct commit_list *find_bisection(struct commit_list *list,
 	struct commit_list *p, *best, *next, *last;
 	struct node_data *weights;
 
+	marker = 0;
+
 	show_list("bisection 2 entry", 0, 0, list);
 
 	/*
-- 
2.8.1.137.g522756c
Previous: Junio C HamanoNext: Christian Couder
Message 31 of 56 in “git bisect improvements”
  1. 00/21 git bisect improvementsStephan Beyer, Apr 10, 2016
  2. 01/21 bisect: write about `bisect next` in documentationStephan Beyer, Apr 10, 2016
  3. 02/21 bisect: allow 'bisect run' if no good commit is knownStephan Beyer, Apr 10, 2016
  4. 03/21 t/test-lib-functions.sh: generalize test_cmp_revStephan Beyer, Apr 10, 2016
  5. Eric SunshineApr 11, 2016
  6. Junio C HamanoApr 15, 2016
  7. Stephan BeyerApr 24, 2016
  8. Junio C HamanoApr 25, 2016
  9. 04/21 t: use test_cmp_rev() where appropriateStephan Beyer, Apr 10, 2016
  10. Eric SunshineApr 11, 2016
  11. Junio C HamanoApr 15, 2016
  12. 05/21 t6030: generalize test to not rely on current implementationStephan Beyer, Apr 10, 2016
  13. Torsten BögershausenApr 10, 2016
  14. Junio C HamanoApr 10, 2016
  15. Stephan BeyerApr 10, 2016
  16. Eric SunshineApr 11, 2016
  17. Junio C HamanoApr 15, 2016
  18. 06/21 bisect: add test for the bisect algorithmStephan Beyer, Apr 10, 2016
  19. Junio C HamanoApr 15, 2016
  20. 07/21 bisect: plug the biggest memory leakStephan Beyer, Apr 10, 2016
  21. Junio C HamanoApr 15, 2016
  22. 08/21 bisect: make bisect compile if DEBUG_BISECT is setStephan Beyer, Apr 10, 2016
  23. Junio C HamanoApr 15, 2016
  24. 09/21 bisect: make algorithm behavior independent of DEBUG_BISECTStephan Beyer, Apr 10, 2016
  25. Junio C HamanoApr 15, 2016
  26. 10/21 bisect: get rid of recursion in count_distance()Stephan Beyer, Apr 10, 2016
  27. Junio C HamanoApr 15, 2016
  28. 11/21 bisect: use struct node_data array instead of int arrayStephan Beyer, Apr 10, 2016
  29. Christian CouderApr 12, 2016
  30. Junio C HamanoApr 15, 2016
  31. 12/21 bisect: replace clear_distance() by unique markersStephan Beyer, Apr 10, 2016
  32. Christian CouderApr 12, 2016
  33. Junio C HamanoApr 15, 2016
  34. 13/21 bisect: use commit instead of commit list as arguments when appropriateStephan Beyer, Apr 10, 2016
  35. Junio C HamanoApr 15, 2016
  36. 14/21 bisect: extract get_distance() function from code duplicationStephan Beyer, Apr 10, 2016
  37. Junio C HamanoApr 15, 2016
  38. 15/21 bisect: introduce distance_direction()Stephan Beyer, Apr 10, 2016
  39. Junio C HamanoApr 15, 2016
  40. 16/21 bisect: make total number of commits globalStephan Beyer, Apr 10, 2016
  41. Christian CouderApr 13, 2016
  42. Junio C HamanoApr 15, 2016
  43. Junio C HamanoApr 16, 2016
  44. 17/21 bisect: rename count_distance() to compute_weight()Stephan Beyer, Apr 10, 2016
  45. Christian CouderApr 13, 2016
  46. Junio C HamanoApr 15, 2016
  47. 18/21 bisect: prepare for different algorithms based on find_allStephan Beyer, Apr 10, 2016
  48. Junio C HamanoApr 15, 2016
  49. 19/21 bisect: use a bottom-up traversal to find relevant weightsStephan Beyer, Apr 10, 2016
  50. Christian CouderApr 13, 2016
  51. Junio C HamanoApr 15, 2016
  52. Junio C HamanoApr 15, 2016
  53. Junio C HamanoApr 26, 2016
  54. 20/21 bisect: compute best bisection in compute_relevant_weights()Stephan Beyer, Apr 10, 2016
  55. 21/21 bisect: get back halfway shortcutStephan Beyer, Apr 10, 2016
  56. Junio C HamanoApr 15, 2016

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