[PATCH 10/25] progress.c: remove the "sparse" mode nano-optimization

["Ævar Arnfjörð Bjarmason" <avarab@gmail.com>]

Revert the code added in 9d81ecb52b5 (progress: add sparse mode to
force 100% complete message, 2019-03-21) for the "sparse" progress
mode, and change its only user added in 430efb8a74b (midx: add
progress indicators in multi-pack-index verify, 2019-03-21) to use the
normal non-sparse progress.c API instead.

The reason for checking the SPARSE_PROGRESS_INTERVAL for every 2^12
objects is to improve performance. It does that, but only in an
isolated and artificial benchmark. In the case of the
"verify_midx_file" user we're in a loop doing various other OID/object
work, the cost of calling display_progress() is entirely lost in the
noise.

Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
---
 midx.c     | 26 +++++++-------------------
 progress.c | 38 +++-----------------------------------
 2 files changed, 10 insertions(+), 54 deletions(-)

diff --git a/midx.c b/midx.c
index 21d6a05e887..d80e68998b8 100644
--- a/midx.c
+++ b/midx.c
@@ -1186,18 +1186,6 @@ static int compare_pair_pos_vs_id(const void *_a, const void *_b)
 	return b->pack_int_id - a->pack_int_id;
 }
 
-/*
- * Limit calls to display_progress() for performance reasons.
- * The interval here was arbitrarily chosen.
- */
-#define SPARSE_PROGRESS_INTERVAL (1 << 12)
-#define midx_display_sparse_progress(progress, n) \
-	do { \
-		uint64_t _n = (n); \
-		if ((_n & (SPARSE_PROGRESS_INTERVAL - 1)) == 0) \
-			display_progress(progress, _n); \
-	} while (0)
-
 int verify_midx_file(struct repository *r, const char *object_dir, unsigned flags)
 {
 	struct pair_pos_vs_id *pairs = NULL;
@@ -1248,8 +1236,8 @@ int verify_midx_file(struct repository *r, const char *object_dir, unsigned flag
 	}
 
 	if (flags & MIDX_PROGRESS)
-		progress = start_sparse_progress(_("Verifying OID order in multi-pack-index"),
-						 m->num_objects - 1);
+		progress = start_progress(_("Verifying OID order in multi-pack-index"),
+					  m->num_objects - 1);
 	for (i = 0; i < m->num_objects - 1; i++) {
 		struct object_id oid1, oid2;
 
@@ -1260,7 +1248,7 @@ int verify_midx_file(struct repository *r, const char *object_dir, unsigned flag
 			midx_report(_("oid lookup out of order: oid[%d] = %s >= %s = oid[%d]"),
 				    i, oid_to_hex(&oid1), oid_to_hex(&oid2), i + 1);
 
-		midx_display_sparse_progress(progress, i + 1);
+		display_progress(progress, i + 1);
 	}
 	stop_progress(&progress);
 
@@ -1277,14 +1265,14 @@ int verify_midx_file(struct repository *r, const char *object_dir, unsigned flag
 	}
 
 	if (flags & MIDX_PROGRESS)
-		progress = start_sparse_progress(_("Sorting objects by packfile"),
-						 m->num_objects);
+		progress = start_progress(_("Sorting objects by packfile"),
+					  m->num_objects);
 	display_progress(progress, 0); /* TODO: Measure QSORT() progress */
 	QSORT(pairs, m->num_objects, compare_pair_pos_vs_id);
 	stop_progress(&progress);
 
 	if (flags & MIDX_PROGRESS)
-		progress = start_sparse_progress(_("Verifying object offsets"), m->num_objects);
+		progress = start_progress(_("Verifying object offsets"), m->num_objects);
 	for (i = 0; i < m->num_objects; i++) {
 		struct object_id oid;
 		struct pack_entry e;
@@ -1318,7 +1306,7 @@ int verify_midx_file(struct repository *r, const char *object_dir, unsigned flag
 			midx_report(_("incorrect object offset for oid[%d] = %s: %"PRIx64" != %"PRIx64),
 				    pairs[i].pos, oid_to_hex(&oid), m_offset, p_offset);
 
-		midx_display_sparse_progress(progress, i + 1);
+		display_progress(progress, i + 1);
 	}
 	stop_progress(&progress);
 
diff --git a/progress.c b/progress.c
index 1ab7d19deb8..912edd4c818 100644
--- a/progress.c
+++ b/progress.c
@@ -37,7 +37,6 @@ struct progress {
 	uint64_t total;
 	unsigned last_percent;
 	unsigned delay;
-	unsigned sparse;
 	struct throughput *throughput;
 	uint64_t start_ns;
 	struct strbuf counters_sb;
@@ -256,7 +255,7 @@ static void clear_progress_signal(void)
 }
 
 static struct progress *start_progress_delay(const char *title, uint64_t total,
-					     unsigned delay, unsigned sparse)
+					     unsigned delay)
 {
 	struct progress *progress = xmalloc(sizeof(*progress));
 	progress->title = title;
@@ -264,7 +263,6 @@ static struct progress *start_progress_delay(const char *title, uint64_t total,
 	progress->last_value = -1;
 	progress->last_percent = -1;
 	progress->delay = delay;
-	progress->sparse = sparse;
 	progress->throughput = NULL;
 	progress->start_ns = getnanotime();
 	strbuf_init(&progress->counters_sb, 0);
@@ -287,40 +285,12 @@ static int get_default_delay(void)
 
 struct progress *start_delayed_progress(const char *title, uint64_t total)
 {
-	return start_progress_delay(title, total, get_default_delay(), 0);
+	return start_progress_delay(title, total, get_default_delay());
 }
 
 struct progress *start_progress(const char *title, uint64_t total)
 {
-	return start_progress_delay(title, total, 0, 0);
-}
-
-/*
- * Here "sparse" means that the caller might use some sampling criteria to
- * decide when to call display_progress() rather than calling it for every
- * integer value in[0 .. total).  In particular, the caller might not call
- * display_progress() for the last value in the range.
- *
- * When "sparse" is set, stop_progress() will automatically force the done
- * message to show 100%.
- */
-struct progress *start_sparse_progress(const char *title, uint64_t total)
-{
-	return start_progress_delay(title, total, 0, 1);
-}
-
-struct progress *start_delayed_sparse_progress(const char *title,
-					       uint64_t total)
-{
-	return start_progress_delay(title, total, get_default_delay(), 1);
-}
-
-static void finish_if_sparse(struct progress *progress)
-{
-	if (progress &&
-	    progress->sparse &&
-	    progress->last_value != progress->total)
-		display_progress(progress, progress->total);
+	return start_progress_delay(title, total, 0);
 }
 
 void stop_progress(struct progress **p_progress)
@@ -328,8 +298,6 @@ void stop_progress(struct progress **p_progress)
 	if (!p_progress)
 		BUG("don't provide NULL to stop_progress");
 
-	finish_if_sparse(*p_progress);
-
 	if (*p_progress) {
 		struct progress *progress = *p_progress;
 		trace2_data_intmax("progress", the_repository, "total_objects",
-- 
2.32.0.599.g3967b4fa4ac