D5942: rust: less set lookups in AncestorsIterator

gracinet (Georges Racinet) phabricator at mercurial-scm.org
Tue Feb 12 12:02:05 UTC 2019


gracinet created this revision.
Herald added subscribers: mercurial-devel, kevincox, durin42.
Herald added a reviewer: hg-reviewers.

REVISION SUMMARY
  This uses the boolean return of `HashSet::insert()` to factor
  pairs of contains()/insert() into a single insert()
  
  On the mozilla-central repository (450k changesets), I get about a bit more
  than 10% better medians in perfancestors (taking the mean of three runs)
  
  Best run for parent changeset:
  
  ! wall 0.106474 comb 0.110000 user 0.110000 sys 0.000000 (median of 93)
  
  Best run fot this changeset:
  
  ! wall 0.093191 comb 0.090000 user 0.090000 sys 0.000000 (median of 100)

REPOSITORY
  rHG Mercurial

REVISION DETAIL
  https://phab.mercurial-scm.org/D5942

AFFECTED FILES
  rust/hg-core/src/ancestors.rs

CHANGE DETAILS

diff --git a/rust/hg-core/src/ancestors.rs b/rust/hg-core/src/ancestors.rs
--- a/rust/hg-core/src/ancestors.rs
+++ b/rust/hg-core/src/ancestors.rs
@@ -79,8 +79,7 @@
 
     #[inline]
     fn conditionally_push_rev(&mut self, rev: Revision) {
-        if self.stoprev <= rev && !self.seen.contains(&rev) {
-            self.seen.insert(rev);
+        if self.stoprev <= rev && self.seen.insert(rev) {
             self.visit.push(rev);
         }
     }
@@ -154,11 +153,10 @@
             Ok(ps) => ps,
             Err(e) => return Some(Err(e)),
         };
-        if p1 < self.stoprev || self.seen.contains(&p1) {
+        if p1 < self.stoprev || !self.seen.insert(p1) {
             self.visit.pop();
         } else {
             *(self.visit.peek_mut().unwrap()) = p1;
-            self.seen.insert(p1);
         };
 
         self.conditionally_push_rev(p2);



To: gracinet, #hg-reviewers
Cc: durin42, kevincox, mercurial-devel


More information about the Mercurial-devel mailing list