copies-rust: move is_ancestor caching within the rust code Now that the OrdMap merging is fast, smaller things start to matters. We move the caching of `is_ancestor` call within the Rust code. This avoid round-trip to Python and help us to shave more time on our slower case: Repo Cases Source-Rev Dest-Rev Old-Time New-Time Difference Factor ------------------------------------------------------------------------------------------------------------------------------------ pypy x0000_revs_x_added_0_copies d1defd0dc478 c9cb1334cc78 : 2.780174 s, 2.137894 s, -0.642280 s, × 0.7690 mozilla-try x0000_revs_xx000_added_x000_copies 89294cd501d9 7ccb2fc7ccb5 : 9.843481 s, 8.100385 s, -1.743096 s, × 0.8229 Note: I would happily have used native code for ancestors computation, however I failed (did not tried hard) to created a rust version that goes as fast as the current C version. Below are full tables for: - this change compared to the previous change - this change compared to filelog performance Repo Cases Source-Rev Dest-Rev Old-Time New-Time Difference Factor ------------------------------------------------------------------------------------------------------------------------------------ mercurial x_revs_x_added_0_copies ad6b123de1c7 39cfcef4f463 : 0.000049 s, 0.000047 s, -0.000002 s, × 0.9592 mercurial x_revs_x_added_x_copies 2b1c78674230 0c1d10351869 : 0.000182 s, 0.000181 s, -0.000001 s, × 0.9945 mercurial x000_revs_x000_added_x_copies 81f8ff2a9bf2 dd3267698d84 : 0.005872 s, 0.005852 s, -0.000020 s, × 0.9966 pypy x_revs_x_added_0_copies aed021ee8ae8 099ed31b181b : 0.000229 s, 0.000229 s, +0.000000 s, × 1.0000 pypy x_revs_x000_added_0_copies 4aa4e1f8e19a 359343b9ac0e : 0.000058 s, 0.000058 s, +0.000000 s, × 1.0000 pypy x_revs_x_added_x_copies ac52eb7bbbb0 72e022663155 : 0.000148 s, 0.000146 s, -0.000002 s, × 0.9865 pypy x_revs_x00_added_x_copies c3b14617fbd7 ace7255d9a26 : 0.001205 s, 0.001206 s, +0.000001 s, × 1.0008 pypy x_revs_x000_added_x000_copies df6f7a526b60 a83dc6a2d56f : 0.025662 s, 0.025275 s, -0.000387 s, × 0.9849 pypy x000_revs_xx00_added_0_copies 89a76aede314 2f22446ff07e : 0.080113 s, 0.080303 s, +0.000190 s, × 1.0024 pypy x000_revs_x000_added_x_copies 8a3b5bfd266e 2c68e87c3efe : 0.153030 s, 0.152641 s, -0.000389 s, × 0.9975 pypy x000_revs_x000_added_x000_copies 89a76aede314 7b3dda341c84 : 0.098774 s, 0.099107 s, +0.000333 s, × 1.0034 pypy x0000_revs_x_added_0_copies d1defd0dc478 c9cb1334cc78 : 2.780174 s, 2.137894 s, -0.642280 s, × 0.7690 pypy x0000_revs_xx000_added_0_copies bf2c629d0071 4ffed77c095c : 0.022218 s, 0.022202 s, -0.000016 s, × 0.9993 pypy x0000_revs_xx000_added_x000_copies 08ea3258278e d9fa043f30c0 : 0.252125 s, 0.228946 s, -0.023179 s, × 0.9081 netbeans x_revs_x_added_0_copies fb0955ffcbcd a01e9239f9e7 : 0.000186 s, 0.000186 s, +0.000000 s, × 1.0000 netbeans x_revs_x000_added_0_copies 6f360122949f 20eb231cc7d0 : 0.000133 s, 0.000133 s, +0.000000 s, × 1.0000 netbeans x_revs_x_added_x_copies 1ada3faf6fb6 5a39d12eecf4 : 0.000320 s, 0.000320 s, +0.000000 s, × 1.0000 netbeans x_revs_x00_added_x_copies 35be93ba1e2c 9eec5e90c05f : 0.001336 s, 0.001339 s, +0.000003 s, × 1.0022 netbeans x000_revs_xx00_added_0_copies eac3045b4fdd 51d4ae7f1290 : 0.015573 s, 0.015694 s, +0.000121 s, × 1.0078 netbeans x000_revs_x000_added_x_copies e2063d266acd 6081d72689dc : 0.018667 s, 0.018457 s, -0.000210 s, × 0.9888 netbeans x000_revs_x000_added_x000_copies ff453e9fee32 411350406ec2 : 0.112534 s, 0.111691 s, -0.000843 s, × 0.9925 netbeans x0000_revs_xx000_added_x000_copies 588c2d1ced70 1aad62e59ddd : 1.231869 s, 1.166017 s, -0.065852 s, × 0.9465 mozilla-central x_revs_x_added_0_copies 3697f962bb7b 7015fcdd43a2 : 0.000197 s, 0.000197 s, +0.000000 s, × 1.0000 mozilla-central x_revs_x000_added_0_copies dd390860c6c9 40d0c5bed75d : 0.000637 s, 0.000626 s, -0.000011 s, × 0.9827 mozilla-central x_revs_x_added_x_copies 8d198483ae3b 14207ffc2b2f : 0.000303 s, 0.000303 s, +0.000000 s, × 1.0000 mozilla-central x_revs_x00_added_x_copies 98cbc58cc6bc 446a150332c3 : 0.001663 s, 0.001679 s, +0.000016 s, × 1.0096 mozilla-central x_revs_x000_added_x000_copies 3c684b4b8f68 0a5e72d1b479 : 0.007008 s, 0.006947 s, -0.000061 s, × 0.9913 mozilla-central x_revs_x0000_added_x0000_copies effb563bb7e5 c07a39dc4e80 : 0.127385 s, 0.133070 s, +0.005685 s, × 1.0446 mozilla-central x000_revs_xx00_added_0_copies 6100d773079a 04a55431795e : 0.008740 s, 0.008705 s, -0.000035 s, × 0.9960 mozilla-central x000_revs_x000_added_x_copies 9f17a6fc04f9 2d37b966abed : 0.005783 s, 0.005913 s, +0.000130 s, × 1.0225 mozilla-central x000_revs_x000_added_x000_copies 7c97034feb78 4407bd0c6330 : 0.102184 s, 0.101373 s, -0.000811 s, × 0.9921 mozilla-central x0000_revs_xx000_added_0_copies 9eec5917337d 67118cc6dcad : 0.046220 s, 0.046526 s, +0.000306 s, × 1.0066 mozilla-central x0000_revs_xx000_added_x000_copies f78c615a656c 96a38b690156 : 0.315271 s, 0.313954 s, -0.001317 s, × 0.9958 mozilla-central x00000_revs_x0000_added_x0000_copies 6832ae71433c 4c222a1d9a00 : 3.478747 s, 3.367395 s, -0.111352 s, × 0.9680 mozilla-central x00000_revs_x00000_added_x000_copies 76caed42cf7c 1daa622bbe42 : 4.766435 s, 4.691820 s, -0.074615 s, × 0.9843 mozilla-try x_revs_x_added_0_copies aaf6dde0deb8 9790f499805a : 0.001214 s, 0.001199 s, -0.000015 s, × 0.9876 mozilla-try x_revs_x000_added_0_copies d8d0222927b4 5bb8ce8c7450 : 0.001221 s, 0.001216 s, -0.000005 s, × 0.9959 mozilla-try x_revs_x_added_x_copies 092fcca11bdb 936255a0384a : 0.000613 s, 0.000613 s, +0.000000 s, × 1.0000 mozilla-try x_revs_x00_added_x_copies b53d2fadbdb5 017afae788ec : 0.001904 s, 0.001906 s, +0.000002 s, × 1.0011 mozilla-try x_revs_x000_added_x000_copies 20408ad61ce5 6f0ee96e21ad : 0.093000 s, 0.092766 s, -0.000234 s, × 0.9975 mozilla-try x_revs_x0000_added_x0000_copies effb563bb7e5 c07a39dc4e80 : 0.132194 s, 0.136074 s, +0.003880 s, × 1.0294 mozilla-try x000_revs_xx00_added_0_copies 6100d773079a 04a55431795e : 0.009069 s, 0.009067 s, -0.000002 s, × 0.9998 mozilla-try x000_revs_x000_added_x_copies 9f17a6fc04f9 2d37b966abed : 0.006169 s, 0.006243 s, +0.000074 s, × 1.0120 mozilla-try x000_revs_x000_added_x000_copies 1346fd0130e4 4c65cbdabc1f : 0.115540 s, 0.114463 s, -0.001077 s, × 0.9907 mozilla-try x0000_revs_x_added_0_copies 63519bfd42ee a36a2a865d92 : 0.435381 s, 0.433683 s, -0.001698 s, × 0.9961 mozilla-try x0000_revs_x_added_x_copies 9fe69ff0762d bcabf2a78927 : 0.415461 s, 0.411278 s, -0.004183 s, × 0.9899 mozilla-try x0000_revs_xx000_added_x_copies 156f6e2674f2 4d0f2c178e66 : 0.155946 s, 0.155133 s, -0.000813 s, × 0.9948 mozilla-try x0000_revs_xx000_added_0_copies 9eec5917337d 67118cc6dcad : 0.048521 s, 0.048933 s, +0.000412 s, × 1.0085 mozilla-try x0000_revs_xx000_added_x000_copies 89294cd501d9 7ccb2fc7ccb5 : 9.843481 s, 8.100385 s, -1.743096 s, × 0.8229 mozilla-try x0000_revs_x0000_added_x0000_copies e928c65095ed e951f4ad123a : 1.465128 s, 1.446720 s, -0.018408 s, × 0.9874 mozilla-try x00000_revs_x00000_added_0_copies dc8a3ca7010e d16fde900c9c : 1.374283 s, 1.369537 s, -0.004746 s, × 0.9965 mozilla-try x00000_revs_x0000_added_x0000_copies 8d3fafa80d4b eb884023b810 : 5.255158 s, 5.186079 s, -0.069079 s, × 0.9869 Repo Case Source-Rev Dest-Rev filelog sidedata Difference Factor -------------------------------------------------------------------------------------------------------------------------------------- mercurial x_revs_x_added_0_copies ad6b123de1c7 39cfcef4f463 : 0.000892 s, 0.000047 s, -0.000845 s, × 0.052691 mercurial x_revs_x_added_x_copies 2b1c78674230 0c1d10351869 : 0.001823 s, 0.000181 s, -0.001642 s, × 0.099287 mercurial x000_revs_x000_added_x_copies 81f8ff2a9bf2 dd3267698d84 : 0.018063 s, 0.005852 s, -0.012211 s, × 0.323977 pypy x_revs_x_added_0_copies aed021ee8ae8 099ed31b181b : 0.001505 s, 0.000229 s, -0.001276 s, × 0.152159 pypy x_revs_x000_added_0_copies 4aa4e1f8e19a 359343b9ac0e : 0.205895 s, 0.000058 s, -0.205837 s, × 0.000282 pypy x_revs_x_added_x_copies ac52eb7bbbb0 72e022663155 : 0.017021 s, 0.000146 s, -0.016875 s, × 0.008578 pypy x_revs_x00_added_x_copies c3b14617fbd7 ace7255d9a26 : 0.019422 s, 0.001206 s, -0.018216 s, × 0.062095 pypy x_revs_x000_added_x000_copies df6f7a526b60 a83dc6a2d56f : 0.767740 s, 0.025275 s, -0.742465 s, × 0.032921 pypy x000_revs_xx00_added_0_copies 89a76aede314 2f22446ff07e : 1.188515 s, 0.080303 s, -1.108212 s, × 0.067566 pypy x000_revs_x000_added_x_copies 8a3b5bfd266e 2c68e87c3efe : 1.251968 s, 0.152641 s, -1.099327 s, × 0.121921 pypy x000_revs_x000_added_x000_copies 89a76aede314 7b3dda341c84 : 1.616799 s, 0.099107 s, -1.517692 s, × 0.061298 pypy x0000_revs_x_added_0_copies d1defd0dc478 c9cb1334cc78 : 0.001057 s, 2.137894 s, +2.136837 s, × 2022.605487 pypy x0000_revs_xx000_added_0_copies bf2c629d0071 4ffed77c095c : 1.069485 s, 0.022202 s, -1.047283 s, × 0.020760 pypy x0000_revs_xx000_added_x000_copies 08ea3258278e d9fa043f30c0 : 1.350162 s, 0.228946 s, -1.121216 s, × 0.169569 netbeans x_revs_x_added_0_copies fb0955ffcbcd a01e9239f9e7 : 0.028008 s, 0.000186 s, -0.027822 s, × 0.006641 netbeans x_revs_x000_added_0_copies 6f360122949f 20eb231cc7d0 : 0.132281 s, 0.000133 s, -0.132148 s, × 0.001005 netbeans x_revs_x_added_x_copies 1ada3faf6fb6 5a39d12eecf4 : 0.025311 s, 0.000320 s, -0.024991 s, × 0.012643 netbeans x_revs_x00_added_x_copies 35be93ba1e2c 9eec5e90c05f : 0.052957 s, 0.001339 s, -0.051618 s, × 0.025285 netbeans x000_revs_xx00_added_0_copies eac3045b4fdd 51d4ae7f1290 : 0.038011 s, 0.015694 s, -0.022317 s, × 0.412880 netbeans x000_revs_x000_added_x_copies e2063d266acd 6081d72689dc : 0.198639 s, 0.018457 s, -0.180182 s, × 0.092917 netbeans x000_revs_x000_added_x000_copies ff453e9fee32 411350406ec2 : 0.955713 s, 0.111691 s, -0.844022 s, × 0.116867 netbeans x0000_revs_xx000_added_x000_copies 588c2d1ced70 1aad62e59ddd : 3.838886 s, 1.166017 s, -2.672869 s, × 0.303738 mozilla-central x_revs_x_added_0_copies 3697f962bb7b 7015fcdd43a2 : 0.024548 s, 0.000197 s, -0.024351 s, × 0.008025 mozilla-central x_revs_x000_added_0_copies dd390860c6c9 40d0c5bed75d : 0.143394 s, 0.000626 s, -0.142768 s, × 0.004366 mozilla-central x_revs_x_added_x_copies 8d198483ae3b 14207ffc2b2f : 0.026046 s, 0.000303 s, -0.025743 s, × 0.011633 mozilla-central x_revs_x00_added_x_copies 98cbc58cc6bc 446a150332c3 : 0.085440 s, 0.001679 s, -0.083761 s, × 0.019651 mozilla-central x_revs_x000_added_x000_copies 3c684b4b8f68 0a5e72d1b479 : 0.195656 s, 0.006947 s, -0.188709 s, × 0.035506 mozilla-central x_revs_x0000_added_x0000_copies effb563bb7e5 c07a39dc4e80 : 2.190874 s, 0.133070 s, -2.057804 s, × 0.060738 mozilla-central x000_revs_xx00_added_0_copies 6100d773079a 04a55431795e : 0.090208 s, 0.008705 s, -0.081503 s, × 0.096499 mozilla-central x000_revs_x000_added_x_copies 9f17a6fc04f9 2d37b966abed : 0.747367 s, 0.005913 s, -0.741454 s, × 0.007912 mozilla-central x000_revs_x000_added_x000_copies 7c97034feb78 4407bd0c6330 : 1.152863 s, 0.101373 s, -1.051490 s, × 0.087932 mozilla-central x0000_revs_xx000_added_0_copies 9eec5917337d 67118cc6dcad : 6.598336 s, 0.046526 s, -6.551810 s, × 0.007051 mozilla-central x0000_revs_xx000_added_x000_copies f78c615a656c 96a38b690156 : 3.255015 s, 0.313954 s, -2.941061 s, × 0.096452 mozilla-central x00000_revs_x0000_added_x0000_copies 6832ae71433c 4c222a1d9a00 : 15.668041 s, 3.367395 s, -12.300646 s, × 0.214921 mozilla-central x00000_revs_x00000_added_x000_copies 76caed42cf7c 1daa622bbe42 : 20.439638 s, 4.691820 s, -15.747818 s, × 0.229545 mozilla-try x_revs_x_added_0_copies aaf6dde0deb8 9790f499805a : 0.080923 s, 0.001199 s, -0.079724 s, × 0.014817 mozilla-try x_revs_x000_added_0_copies d8d0222927b4 5bb8ce8c7450 : 0.498456 s, 0.001216 s, -0.497240 s, × 0.002440 mozilla-try x_revs_x_added_x_copies 092fcca11bdb 936255a0384a : 0.020798 s, 0.000613 s, -0.020185 s, × 0.029474 mozilla-try x_revs_x00_added_x_copies b53d2fadbdb5 017afae788ec : 0.226930 s, 0.001906 s, -0.225024 s, × 0.008399 mozilla-try x_revs_x000_added_x000_copies 20408ad61ce5 6f0ee96e21ad : 1.113005 s, 0.092766 s, -1.020239 s, × 0.083347 mozilla-try x_revs_x0000_added_x0000_copies effb563bb7e5 c07a39dc4e80 : 2.230671 s, 0.136074 s, -2.094597 s, × 0.061001 mozilla-try x000_revs_xx00_added_0_copies 6100d773079a 04a55431795e : 0.089672 s, 0.009067 s, -0.080605 s, × 0.101113 mozilla-try x000_revs_x000_added_x_copies 9f17a6fc04f9 2d37b966abed : 0.740221 s, 0.006243 s, -0.733978 s, × 0.008434 mozilla-try x000_revs_x000_added_x000_copies 1346fd0130e4 4c65cbdabc1f : 1.185881 s, 0.114463 s, -1.071418 s, × 0.096521 mozilla-try x0000_revs_x_added_0_copies 63519bfd42ee a36a2a865d92 : 0.086072 s, 0.433683 s, +0.347611 s, × 5.038607 mozilla-try x0000_revs_x_added_x_copies 9fe69ff0762d bcabf2a78927 : 0.081321 s, 0.411278 s, +0.329957 s, × 5.057464 mozilla-try x0000_revs_xx000_added_x_copies 156f6e2674f2 4d0f2c178e66 : 7.528370 s, 0.155133 s, -7.373237 s, × 0.020606 mozilla-try x0000_revs_xx000_added_0_copies 9eec5917337d 67118cc6dcad : 6.757368 s, 0.048933 s, -6.708435 s, × 0.007241 mozilla-try x0000_revs_xx000_added_x000_copies 89294cd501d9 7ccb2fc7ccb5 : 7.643752 s, 8.100385 s, +0.456633 s, × 1.059739 mozilla-try x0000_revs_x0000_added_x0000_copies e928c65095ed e951f4ad123a : 9.704242 s, 1.446720 s, -8.257522 s, × 0.149081 mozilla-try x00000_revs_x_added_0_copies 6a320851d377 1ebb79acd503 : 0.092845 s, killed mozilla-try x00000_revs_x00000_added_0_copies dc8a3ca7010e d16fde900c9c : 26.626870 s, 1.369537 s, -25.257333 s, × 0.051434 mozilla-try x00000_revs_x_added_x_copies 5173c4b6f97c 95d83ee7242d : 0.092953 s, killed mozilla-try x00000_revs_x000_added_x_copies 9126823d0e9c ca82787bb23c : 0.227131 s, killed mozilla-try x00000_revs_x0000_added_x0000_copies 8d3fafa80d4b eb884023b810 : 18.884666 s, 5.186079 s, -13.698587 s, × 0.274619 mozilla-try x00000_revs_x00000_added_x0000_copies 1b661134e2ca 1ae03d022d6d : 21.451622 s, killed mozilla-try x00000_revs_x00000_added_x000_copies 9b2a99adc05e 8e29777b48e6 : 25.152558 s, killed Differential Revision: https://phab.mercurial-scm.org/D9303

--- a/mercurial/copies.py	Tue Apr 21 15:00:32 2020 +0200
+++ b/mercurial/copies.py	Fri Oct 02 15:41:31 2020 +0200
@@ -259,7 +259,7 @@
     children = {}
 
     cl = repo.changelog
-    isancestor = cached_is_ancestor(cl.isancestorrev)
+    isancestor = cl.isancestorrev
     missingrevs = cl.findmissingrevs(common=[a.rev()], heads=[b.rev()])
     mrset = set(missingrevs)
     roots = set()
@@ -321,6 +321,8 @@
             list(revs), children, targetrev, revinfo, isancestor
         )
 
+    isancestor = cached_is_ancestor(isancestor)
+
     all_copies = {}
     for r in revs:
         copies = all_copies.pop(r, None)

--- a/rust/hg-core/src/copy_tracing.rs	Tue Apr 21 15:00:32 2020 +0200
+++ b/rust/hg-core/src/copy_tracing.rs	Fri Oct 02 15:41:31 2020 +0200
@@ -64,6 +64,42 @@
     }
 }
 
+/// A struct responsible for answering "is X ancestors of Y" quickly
+///
+/// The structure will delegate ancestors call to a callback, and cache the
+/// result.
+#[derive(Debug)]
+struct AncestorOracle<'a, A: Fn(Revision, Revision) -> bool> {
+    inner: &'a A,
+    pairs: HashMap<(Revision, Revision), bool>,
+}
+
+impl<'a, A: Fn(Revision, Revision) -> bool> AncestorOracle<'a, A> {
+    fn new(func: &'a A) -> Self {
+        Self {
+            inner: func,
+            pairs: HashMap::default(),
+        }
+    }
+
+    /// returns `true` if `anc` is an ancestors of `desc`, `false` otherwise
+    fn is_ancestor(&mut self, anc: Revision, desc: Revision) -> bool {
+        if anc > desc {
+            false
+        } else if anc == desc {
+            true
+        } else {
+            if let Some(b) = self.pairs.get(&(anc, desc)) {
+                *b
+            } else {
+                let b = (self.inner)(anc, desc);
+                self.pairs.insert((anc, desc), b);
+                b
+            }
+        }
+    }
+}
+
 /// Same as mercurial.copies._combine_changeset_copies, but in Rust.
 ///
 /// Arguments are:
@@ -77,14 +113,15 @@
 ///   * ChangedFiles
 /// isancestors(low_rev, high_rev): callback to check if a revision is an
 ///                                 ancestor of another
-pub fn combine_changeset_copies(
+pub fn combine_changeset_copies<A: Fn(Revision, Revision) -> bool>(
     revs: Vec<Revision>,
     children: HashMap<Revision, Vec<Revision>>,
     target_rev: Revision,
     rev_info: &impl Fn(Revision) -> RevInfo,
-    is_ancestor: &impl Fn(Revision, Revision) -> bool,
+    is_ancestor: &A,
 ) -> PathCopies {
     let mut all_copies = HashMap::new();
+    let mut oracle = AncestorOracle::new(is_ancestor);
 
     for rev in revs {
         // Retrieve data computed in a previous iteration
@@ -168,7 +205,7 @@
                         _ => unreachable!(),
                     };
                     let merged_copies =
-                        merge_copies_dict(minor, major, &changes, is_ancestor);
+                        merge_copies_dict(minor, major, &changes, &mut oracle);
                     all_copies.insert(child, merged_copies);
                 }
             };
@@ -194,11 +231,11 @@
 /// In case of conflict, value from "major" will be picked, unless in some
 /// cases. See inline documentation for details.
 #[allow(clippy::if_same_then_else)]
-fn merge_copies_dict(
+fn merge_copies_dict<A: Fn(Revision, Revision) -> bool>(
     minor: TimeStampedPathCopies,
     major: TimeStampedPathCopies,
     changes: &ChangedFiles,
-    is_ancestor: &impl Fn(Revision, Revision) -> bool,
+    oracle: &mut AncestorOracle<A>,
 ) -> TimeStampedPathCopies {
     if minor.is_empty() {
         return major;
@@ -244,7 +281,8 @@
                         // If the two entry are identical, no need to do
                         // anything (but diff should not have yield them)
                         unreachable!();
-                    } else if is_ancestor(src_major.rev, src_minor.rev) {
+                    } else if oracle.is_ancestor(src_major.rev, src_minor.rev)
+                    {
                         pick_minor();
                     } else {
                         pick_major();
@@ -271,7 +309,7 @@
                     // each side might conflict.  The major side will win such
                     // conflict.
                     pick_major();
-                } else if is_ancestor(src_major.rev, src_minor.rev) {
+                } else if oracle.is_ancestor(src_major.rev, src_minor.rev) {
                     // If the minor side is strictly newer than the major side,
                     // it should be kept.
                     pick_minor();
@@ -279,7 +317,7 @@
                     // without any special case, the "major" value win other
                     // the "minor" one.
                     pick_major();
-                } else if is_ancestor(src_minor.rev, src_major.rev) {
+                } else if oracle.is_ancestor(src_minor.rev, src_major.rev) {
                     // the "major" rev is a direct ancestors of "minor", any
                     // different value should overwrite
                     pick_major();