Merge branch 'nd/trace-index-ops'

* nd/trace-index-ops:
  trace: measure where the time is spent in the index-heavy operations

diff --cc dir.c
Simple merge

diff --cc read-cache.c
index f9871cde33ef5423f6e7e4e9d41ea7775bdb10f2,eac74bc9f17d69c304461a3174e3ee0888ea1be9..82ba2287e1bbe6121a9c1c5e9b20a9b352886f95
--- 1/read-cache.c
--- 2/read-cache.c
+++ b/read-cache.c
@@@ -1862,15 -1865,17 +1864,16 @@@ unmap
   * This way, shared index can be removed if they have not been used
   * for some time.
   */
 -static void freshen_shared_index(char *base_sha1_hex, int warn)
 +static void freshen_shared_index(const char *shared_index, int warn)
  {
 -      char *shared_index = git_pathdup("sharedindex.%s", base_sha1_hex);
        if (!check_and_freshen_file(shared_index, 1) && warn)
                warning("could not freshen shared index '%s'", shared_index);
 -      free(shared_index);
  }
  
 -int read_index_from(struct index_state *istate, const char *path)
 +int read_index_from(struct index_state *istate, const char *path,
 +                  const char *gitdir)
  {
+       uint64_t start = getnanotime();
        struct split_index *split_index;
        int ret;
        char *base_sha1_hex;
@@@ -1901,10 -1907,10 +1905,11 @@@
                    base_sha1_hex, base_path,
                    sha1_to_hex(split_index->base->sha1));
  
 -      freshen_shared_index(base_sha1_hex, 0);
 +      freshen_shared_index(base_path, 0);
        merge_base_index(istate);
        post_read_index_from(istate);
+       trace_performance_since(start, "read cache %s", base_path);
 +      free(base_path);
        return ret;
  }