diff: halt tree-diff early after max_changes
When computing the changed-paths bloom filters for the commit-graph,
we limit the size of the filter by restricting the number of paths
in the diff. Instead of computing a large diff and then ignoring the
result, it is better to halt the diff computation early.
Create a new "max_changes" option in struct diff_options. If non-zero,
then halt the diff computation after discovering strictly more changed
paths. This includes paths corresponding to trees that change.
Use this max_changes option in the bloom filter calculations. This
reduces the time taken to compute the filters for the Linux kernel
repo from 2m50s to 2m35s. On a large internal repository with ~500
commits that perform tree-wide changes, the time reduced from
6m15s to 3m48s.
Signed-off-by: Derrick Stolee <dstolee@microsoft.com>
Signed-off-by: Garima Singh <garima.singh@microsoft.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
diff --git a/diff.h b/diff.h
index 6febe7e..9443dc1 100644
--- a/diff.h
+++ b/diff.h
@@ -285,6 +285,11 @@ struct diff_options {
/* Number of hexdigits to abbreviate raw format output to. */
int abbrev;
+ /* If non-zero, then stop computing after this many changes. */
+ int max_changes;
+ /* For internal use only. */
+ int num_changes;
+
int ita_invisible_in_index;
/* white-space error highlighting */
#define WSEH_NEW (1<<12)
