[PATCH 10/14] pack-objects: add trace2 regions

["Derrick Stolee via GitGitGadget" <gitgitgadget@gmail.com>]

From: Derrick Stolee <dstolee@microsoft.com>

When studying the performance of 'git push' we would like to know
how much time is spent at various parts of the command. One area
that could cause performance trouble is 'git pack-objects'.

Add trace2 regions around the three main actions taken in this
command:

1. Enumerate objects.
2. Prepare pack.
3. Write pack-file.

Signed-off-by: Derrick Stolee <dstolee@microsoft.com>
---
 builtin/pack-objects.c | 12 +++++++++++-
 1 file changed, 11 insertions(+), 1 deletion(-)

diff --git a/builtin/pack-objects.c b/builtin/pack-objects.c
index 889df2c755..6708529e3c 100644
--- a/builtin/pack-objects.c
+++ b/builtin/pack-objects.c
@@ -33,6 +33,7 @@
 #include "object-store.h"
 #include "dir.h"
 #include "midx.h"
+#include "trace2.h"
 
 #define IN_PACK(obj) oe_in_pack(&to_pack, obj)
 #define SIZE(obj) oe_size(&to_pack, obj)
@@ -3472,6 +3473,7 @@ int cmd_pack_objects(int argc, const char **argv, const char *prefix)
 		}
 	}
 
+	trace2_region_enter("pack-objects", "enumerate-objects", the_repository);
 	prepare_packing_data(the_repository, &to_pack);
 
 	if (progress)
@@ -3486,12 +3488,20 @@ int cmd_pack_objects(int argc, const char **argv, const char *prefix)
 	if (include_tag && nr_result)
 		for_each_ref(add_ref_tag, NULL);
 	stop_progress(&progress_state);
+	trace2_region_leave("pack-objects", "enumerate-objects", the_repository);
 
 	if (non_empty && !nr_result)
 		return 0;
-	if (nr_result)
+	if (nr_result) {
+		trace2_region_enter("pack-objects", "prepare-pack", the_repository);
 		prepare_pack(window, depth);
+		trace2_region_leave("pack-objects", "prepare-pack", the_repository);
+	}
+
+	trace2_region_enter("pack-objects", "write-pack-file", the_repository);
 	write_pack_file();
+	trace2_region_leave("pack-objects", "write-pack-file", the_repository);
+
 	if (progress)
 		fprintf_ln(stderr,
 			   _("Total %"PRIu32" (delta %"PRIu32"),"
-- 
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