[PATCH 4/8] cache-tree: trace regions for I/O

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

From: Derrick Stolee <dstolee@microsoft.com>

As we write or read the cached tree index extension, it can be good to
isolate how much of the file I/O time is spent constructing this
in-memory tree from the existing index or writing it out again to the
new index file. Use trace2 regions to indicate that we are spending time
on this operation.

Signed-off-by: Derrick Stolee <dstolee@microsoft.com>
---
 cache-tree.c | 11 ++++++++++-
 1 file changed, 10 insertions(+), 1 deletion(-)

diff --git a/cache-tree.c b/cache-tree.c
index 9efb6748662..45fb57b17f3 100644
--- a/cache-tree.c
+++ b/cache-tree.c
@@ -494,7 +494,9 @@ static void write_one(struct strbuf *buffer, struct cache_tree *it,
 
 void cache_tree_write(struct strbuf *sb, struct cache_tree *root)
 {
+	trace2_region_enter("cache_tree", "write", the_repository);
 	write_one(sb, root, "", 0);
+	trace2_region_leave("cache_tree", "write", the_repository);
 }
 
 static struct cache_tree *read_one(const char **buffer, unsigned long *size_p)
@@ -583,9 +585,16 @@ static struct cache_tree *read_one(const char **buffer, unsigned long *size_p)
 
 struct cache_tree *cache_tree_read(const char *buffer, unsigned long size)
 {
+	struct cache_tree *result;
+
 	if (buffer[0])
 		return NULL; /* not the whole tree */
-	return read_one(&buffer, &size);
+
+	trace2_region_enter("cache_tree", "read", the_repository);
+	result = read_one(&buffer, &size);
+	trace2_region_leave("cache_tree", "read", the_repository);
+
+	return result;
 }
 
 static struct cache_tree *cache_tree_find(struct cache_tree *it, const char *path)
-- 
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