--- a/rust/Cargo.lock	Mon Dec 02 14:44:26 2019 +0100
+++ b/rust/Cargo.lock	Mon Oct 14 13:57:30 2019 +0200
@@ -32,6 +32,15 @@
 source = "registry+https://github.com/rust-lang/crates.io-index"
 
 [[package]]
+name = "c2-chacha"
+version = "0.2.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "lazy_static 1.4.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "ppv-lite86 0.2.5 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
+[[package]]
 name = "cfg-if"
 version = "0.1.10"
 source = "registry+https://github.com/rust-lang/crates.io-index"
@@ -105,6 +114,16 @@
 source = "registry+https://github.com/rust-lang/crates.io-index"
 
 [[package]]
+name = "getrandom"
+version = "0.1.12"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "cfg-if 0.1.10 (registry+https://github.com/rust-lang/crates.io-index)",
+ "libc 0.2.64 (registry+https://github.com/rust-lang/crates.io-index)",
+ "wasi 0.7.0 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
+[[package]]
 name = "hg-core"
 version = "0.1.0"
 dependencies = [
@@ -115,6 +134,7 @@
  "rand_pcg 0.1.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "rayon 1.2.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "regex 1.3.1 (registry+https://github.com/rust-lang/crates.io-index)",
+ "twox-hash 1.5.0 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
 [[package]]
@@ -179,6 +199,11 @@
 ]
 
 [[package]]
+name = "ppv-lite86"
+version = "0.2.5"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+
+[[package]]
 name = "python27-sys"
 version = "0.3.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
@@ -215,6 +240,18 @@
 ]
 
 [[package]]
+name = "rand"
+version = "0.7.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "getrandom 0.1.12 (registry+https://github.com/rust-lang/crates.io-index)",
+ "libc 0.2.64 (registry+https://github.com/rust-lang/crates.io-index)",
+ "rand_chacha 0.2.1 (registry+https://github.com/rust-lang/crates.io-index)",
+ "rand_core 0.5.1 (registry+https://github.com/rust-lang/crates.io-index)",
+ "rand_hc 0.2.0 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
+[[package]]
 name = "rand_chacha"
 version = "0.1.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
@@ -224,6 +261,15 @@
 ]
 
 [[package]]
+name = "rand_chacha"
+version = "0.2.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "c2-chacha 0.2.2 (registry+https://github.com/rust-lang/crates.io-index)",
+ "rand_core 0.5.1 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
+[[package]]
 name = "rand_core"
 version = "0.3.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
@@ -237,6 +283,14 @@
 source = "registry+https://github.com/rust-lang/crates.io-index"
 
 [[package]]
+name = "rand_core"
+version = "0.5.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "getrandom 0.1.12 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
+[[package]]
 name = "rand_hc"
 version = "0.1.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
@@ -245,6 +299,14 @@
 ]
 
 [[package]]
+name = "rand_hc"
+version = "0.2.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "rand_core 0.5.1 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
+[[package]]
 name = "rand_isaac"
 version = "0.1.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
@@ -373,6 +435,19 @@
 ]
 
 [[package]]
+name = "twox-hash"
+version = "1.5.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "rand 0.7.2 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
+[[package]]
+name = "wasi"
+version = "0.7.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+
+[[package]]
 name = "winapi"
 version = "0.3.8"
 source = "registry+https://github.com/rust-lang/crates.io-index"
@@ -397,6 +472,7 @@
 "checksum autocfg 0.1.6 (registry+https://github.com/rust-lang/crates.io-index)" = "b671c8fb71b457dd4ae18c4ba1e59aa81793daacc361d82fcd410cef0d491875"
 "checksum bitflags 1.2.1 (registry+https://github.com/rust-lang/crates.io-index)" = "cf1de2fe8c75bc145a2f577add951f8134889b4795d47466a54a5c846d691693"
 "checksum byteorder 1.3.2 (registry+https://github.com/rust-lang/crates.io-index)" = "a7c3dd8985a7111efc5c80b44e23ecdd8c007de8ade3b96595387e812b957cf5"
+"checksum c2-chacha 0.2.2 (registry+https://github.com/rust-lang/crates.io-index)" = "7d64d04786e0f528460fc884753cf8dddcc466be308f6026f8e355c41a0e4101"
 "checksum cfg-if 0.1.10 (registry+https://github.com/rust-lang/crates.io-index)" = "4785bdd1c96b2a846b2bd7cc02e86b6b3dbf14e7e53446c4f54c92a361040822"
 "checksum cloudabi 0.0.3 (registry+https://github.com/rust-lang/crates.io-index)" = "ddfc5b9aa5d4507acaf872de71051dfd0e309860e88966e1051e462a077aac4f"
 "checksum cpython 0.3.0 (registry+https://github.com/rust-lang/crates.io-index)" = "85532c648315aeb0829ad216a6a29aa3212cf9319bc7f6daf1404aa0bdd1485f"
@@ -406,6 +482,7 @@
 "checksum crossbeam-utils 0.6.6 (registry+https://github.com/rust-lang/crates.io-index)" = "04973fa96e96579258a5091af6003abde64af786b860f18622b82e026cca60e6"
 "checksum either 1.5.3 (registry+https://github.com/rust-lang/crates.io-index)" = "bb1f6b1ce1c140482ea30ddd3335fc0024ac7ee112895426e0a629a6c20adfe3"
 "checksum fuchsia-cprng 0.1.1 (registry+https://github.com/rust-lang/crates.io-index)" = "a06f77d526c1a601b7c4cdd98f54b5eaabffc14d5f2f0296febdc7f357c6d3ba"
+"checksum getrandom 0.1.12 (registry+https://github.com/rust-lang/crates.io-index)" = "473a1265acc8ff1e808cd0a1af8cee3c2ee5200916058a2ca113c29f2d903571"
 "checksum lazy_static 1.4.0 (registry+https://github.com/rust-lang/crates.io-index)" = "e2abad23fbc42b3700f2f279844dc832adb2b2eb069b2df918f455c4e18cc646"
 "checksum libc 0.2.64 (registry+https://github.com/rust-lang/crates.io-index)" = "74dfca3d9957906e8d1e6a0b641dc9a59848e793f1da2165889fd4f62d10d79c"
 "checksum memchr 2.2.1 (registry+https://github.com/rust-lang/crates.io-index)" = "88579771288728879b57485cc7d6b07d648c9f0141eb955f8ab7f9d45394468e"
@@ -413,13 +490,18 @@
 "checksum nodrop 0.1.14 (registry+https://github.com/rust-lang/crates.io-index)" = "72ef4a56884ca558e5ddb05a1d1e7e1bfd9a68d9ed024c21704cc98872dae1bb"
 "checksum num-traits 0.2.8 (registry+https://github.com/rust-lang/crates.io-index)" = "6ba9a427cfca2be13aa6f6403b0b7e7368fe982bfa16fccc450ce74c46cd9b32"
 "checksum num_cpus 1.10.1 (registry+https://github.com/rust-lang/crates.io-index)" = "bcef43580c035376c0705c42792c294b66974abbfd2789b511784023f71f3273"
+"checksum ppv-lite86 0.2.5 (registry+https://github.com/rust-lang/crates.io-index)" = "e3cbf9f658cdb5000fcf6f362b8ea2ba154b9f146a61c7a20d647034c6b6561b"
 "checksum python27-sys 0.3.0 (registry+https://github.com/rust-lang/crates.io-index)" = "372555e88a6bc8109eb641380240dc8d25a128fc48363ec9075664daadffdd5b"
 "checksum python3-sys 0.3.0 (registry+https://github.com/rust-lang/crates.io-index)" = "f3a8ebed3f1201fda179f3960609dbbc10cd8c75e9f2afcb03788278f367d8ea"
 "checksum rand 0.6.5 (registry+https://github.com/rust-lang/crates.io-index)" = "6d71dacdc3c88c1fde3885a3be3fbab9f35724e6ce99467f7d9c5026132184ca"
+"checksum rand 0.7.2 (registry+https://github.com/rust-lang/crates.io-index)" = "3ae1b169243eaf61759b8475a998f0a385e42042370f3a7dbaf35246eacc8412"
 "checksum rand_chacha 0.1.1 (registry+https://github.com/rust-lang/crates.io-index)" = "556d3a1ca6600bfcbab7c7c91ccb085ac7fbbcd70e008a98742e7847f4f7bcef"
+"checksum rand_chacha 0.2.1 (registry+https://github.com/rust-lang/crates.io-index)" = "03a2a90da8c7523f554344f921aa97283eadf6ac484a6d2a7d0212fa7f8d6853"
 "checksum rand_core 0.3.1 (registry+https://github.com/rust-lang/crates.io-index)" = "7a6fdeb83b075e8266dcc8762c22776f6877a63111121f5f8c7411e5be7eed4b"
 "checksum rand_core 0.4.2 (registry+https://github.com/rust-lang/crates.io-index)" = "9c33a3c44ca05fa6f1807d8e6743f3824e8509beca625669633be0acbdf509dc"
+"checksum rand_core 0.5.1 (registry+https://github.com/rust-lang/crates.io-index)" = "90bde5296fc891b0cef12a6d03ddccc162ce7b2aff54160af9338f8d40df6d19"
 "checksum rand_hc 0.1.0 (registry+https://github.com/rust-lang/crates.io-index)" = "7b40677c7be09ae76218dc623efbf7b18e34bced3f38883af07bb75630a21bc4"
+"checksum rand_hc 0.2.0 (registry+https://github.com/rust-lang/crates.io-index)" = "ca3129af7b92a17112d59ad498c6f81eaf463253766b90396d39ea7a39d6613c"
 "checksum rand_isaac 0.1.1 (registry+https://github.com/rust-lang/crates.io-index)" = "ded997c9d5f13925be2a6fd7e66bf1872597f759fd9dd93513dd7e92e5a5ee08"
 "checksum rand_jitter 0.1.4 (registry+https://github.com/rust-lang/crates.io-index)" = "1166d5c91dc97b88d1decc3285bb0a99ed84b05cfd0bc2341bdf2d43fc41e39b"
 "checksum rand_os 0.1.3 (registry+https://github.com/rust-lang/crates.io-index)" = "7b75f676a1e053fc562eafbb47838d67c84801e38fc1ba459e8f180deabd5071"
@@ -435,6 +517,8 @@
 "checksum semver 0.9.0 (registry+https://github.com/rust-lang/crates.io-index)" = "1d7eb9ef2c18661902cc47e535f9bc51b78acd254da71d375c2f6720d9a40403"
 "checksum semver-parser 0.7.0 (registry+https://github.com/rust-lang/crates.io-index)" = "388a1df253eca08550bef6c72392cfe7c30914bf41df5269b68cbd6ff8f570a3"
 "checksum thread_local 0.3.6 (registry+https://github.com/rust-lang/crates.io-index)" = "c6b53e329000edc2b34dbe8545fd20e55a333362d0a321909685a19bd28c3f1b"
+"checksum twox-hash 1.5.0 (registry+https://github.com/rust-lang/crates.io-index)" = "3bfd5b7557925ce778ff9b9ef90e3ade34c524b5ff10e239c69a42d546d2af56"
+"checksum wasi 0.7.0 (registry+https://github.com/rust-lang/crates.io-index)" = "b89c3ce4ce14bdc6fb6beaf9ec7928ca331de5df7e5ea278375642a2f478570d"
 "checksum winapi 0.3.8 (registry+https://github.com/rust-lang/crates.io-index)" = "8093091eeb260906a183e6ae1abdba2ef5ef2257a21801128899c3fc699229c6"
 "checksum winapi-i686-pc-windows-gnu 0.4.0 (registry+https://github.com/rust-lang/crates.io-index)" = "ac3b87c63620426dd9b991e5ce0329eff545bccbbb34f3be09ff6fb6ab51b7b6"
 "checksum winapi-x86_64-pc-windows-gnu 0.4.0 (registry+https://github.com/rust-lang/crates.io-index)" = "712e227841d057c1ee1cd2fb22fa7e5a5461ae8e48fa2ca79ec42cfc1931183f"

--- a/rust/hg-core/Cargo.toml	Mon Dec 02 14:44:26 2019 +0100
+++ b/rust/hg-core/Cargo.toml	Mon Oct 14 13:57:30 2019 +0200
@@ -14,5 +14,6 @@
 memchr = "2.2.0"
 rand = "0.6.5"
 rand_pcg = "0.1.1"
+rayon = "1.2.0"
 regex = "1.1.0"
-rayon = "1.2.0"
+twox-hash = "1.5.0"

--- a/rust/hg-core/src/dirstate.rs	Mon Dec 02 14:44:26 2019 +0100
+++ b/rust/hg-core/src/dirstate.rs	Mon Oct 14 13:57:30 2019 +0200
@@ -5,9 +5,8 @@
 // This software may be used and distributed according to the terms of the
 // GNU General Public License version 2 or any later version.
 
-use crate::{utils::hg_path::HgPathBuf, DirstateParseError};
+use crate::{utils::hg_path::HgPathBuf, DirstateParseError, FastHashMap};
 use std::collections::hash_map;
-use std::collections::HashMap;
 use std::convert::TryFrom;
 
 pub mod dirs_multiset;
@@ -37,9 +36,9 @@
 /// merge.
 pub const SIZE_FROM_OTHER_PARENT: i32 = -2;
 
-pub type StateMap = HashMap<HgPathBuf, DirstateEntry>;
+pub type StateMap = FastHashMap<HgPathBuf, DirstateEntry>;
 pub type StateMapIter<'a> = hash_map::Iter<'a, HgPathBuf, DirstateEntry>;
-pub type CopyMap = HashMap<HgPathBuf, HgPathBuf>;
+pub type CopyMap = FastHashMap<HgPathBuf, HgPathBuf>;
 pub type CopyMapIter<'a> = hash_map::Iter<'a, HgPathBuf, HgPathBuf>;
 
 #[derive(Copy, Clone, Debug, Eq, PartialEq)]

--- a/rust/hg-core/src/dirstate/dirs_multiset.rs	Mon Dec 02 14:44:26 2019 +0100
+++ b/rust/hg-core/src/dirstate/dirs_multiset.rs	Mon Oct 14 13:57:30 2019 +0200
@@ -11,16 +11,16 @@
 use crate::utils::hg_path::{HgPath, HgPathBuf};
 use crate::{
     dirstate::EntryState, utils::files, DirstateEntry, DirstateMapError,
+    FastHashMap,
 };
 use std::collections::hash_map::{self, Entry};
-use std::collections::HashMap;
 
 // could be encapsulated if we care API stability more seriously
 pub type DirsMultisetIter<'a> = hash_map::Keys<'a, HgPathBuf, u32>;
 
 #[derive(PartialEq, Debug)]
 pub struct DirsMultiset {
-    inner: HashMap<HgPathBuf, u32>,
+    inner: FastHashMap<HgPathBuf, u32>,
 }
 
 impl DirsMultiset {
@@ -28,11 +28,11 @@
     ///
     /// If `skip_state` is provided, skips dirstate entries with equal state.
     pub fn from_dirstate(
-        vec: &HashMap<HgPathBuf, DirstateEntry>,
+        vec: &FastHashMap<HgPathBuf, DirstateEntry>,
         skip_state: Option<EntryState>,
     ) -> Self {
         let mut multiset = DirsMultiset {
-            inner: HashMap::new(),
+            inner: FastHashMap::default(),
         };
 
         for (filename, DirstateEntry { state, .. }) in vec {
@@ -52,7 +52,7 @@
     /// Initializes the multiset from a manifest.
     pub fn from_manifest(vec: &Vec<HgPathBuf>) -> Self {
         let mut multiset = DirsMultiset {
-            inner: HashMap::new(),
+            inner: FastHashMap::default(),
         };
 
         for filename in vec {
@@ -127,7 +127,6 @@
 #[cfg(test)]
 mod tests {
     use super::*;
-    use std::collections::HashMap;
 
     #[test]
     fn test_delete_path_path_not_found() {
@@ -243,13 +242,13 @@
     fn test_dirsmultiset_new_empty() {
         let new = DirsMultiset::from_manifest(&vec![]);
         let expected = DirsMultiset {
-            inner: HashMap::new(),
+            inner: FastHashMap::default(),
         };
         assert_eq!(expected, new);
 
-        let new = DirsMultiset::from_dirstate(&HashMap::new(), None);
+        let new = DirsMultiset::from_dirstate(&FastHashMap::default(), None);
         let expected = DirsMultiset {
-            inner: HashMap::new(),
+            inner: FastHashMap::default(),
         };
         assert_eq!(expected, new);
     }

--- a/rust/hg-core/src/dirstate/dirstate_map.rs	Mon Dec 02 14:44:26 2019 +0100
+++ b/rust/hg-core/src/dirstate/dirstate_map.rs	Mon Oct 14 13:57:30 2019 +0200
@@ -13,16 +13,16 @@
         hg_path::{HgPath, HgPathBuf},
     },
     CopyMap, DirsMultiset, DirstateEntry, DirstateError, DirstateMapError,
-    DirstateParents, DirstateParseError, StateMap,
+    DirstateParents, DirstateParseError, FastHashMap, StateMap,
 };
 use core::borrow::Borrow;
-use std::collections::{HashMap, HashSet};
+use std::collections::HashSet;
 use std::convert::TryInto;
 use std::iter::FromIterator;
 use std::ops::Deref;
 use std::time::Duration;
 
-pub type FileFoldMap = HashMap<HgPathBuf, HgPathBuf>;
+pub type FileFoldMap = FastHashMap<HgPathBuf, HgPathBuf>;
 
 const NULL_ID: [u8; 20] = [0; 20];
 const MTIME_UNSET: i32 = -1;
@@ -327,7 +327,7 @@
         if let Some(ref file_fold_map) = self.file_fold_map {
             return file_fold_map;
         }
-        let mut new_file_fold_map = FileFoldMap::new();
+        let mut new_file_fold_map = FileFoldMap::default();
         for (filename, DirstateEntry { state, .. }) in self.state_map.borrow()
         {
             if *state == EntryState::Removed {

--- a/rust/hg-core/src/dirstate/parsers.rs	Mon Dec 02 14:44:26 2019 +0100
+++ b/rust/hg-core/src/dirstate/parsers.rs	Mon Oct 14 13:57:30 2019 +0200
@@ -157,13 +157,12 @@
 #[cfg(test)]
 mod tests {
     use super::*;
-    use crate::utils::hg_path::HgPathBuf;
-    use std::collections::HashMap;
+    use crate::{utils::hg_path::HgPathBuf, FastHashMap};
 
     #[test]
     fn test_pack_dirstate_empty() {
-        let mut state_map: StateMap = HashMap::new();
-        let copymap = HashMap::new();
+        let mut state_map: StateMap = FastHashMap::default();
+        let copymap = FastHashMap::default();
         let parents = DirstateParents {
             p1: *b"12345678910111213141",
             p2: *b"00000000000000000000",
@@ -194,7 +193,7 @@
         .collect();
         let mut state_map = expected_state_map.clone();
 
-        let copymap = HashMap::new();
+        let copymap = FastHashMap::default();
         let parents = DirstateParents {
             p1: *b"12345678910111213141",
             p2: *b"00000000000000000000",
@@ -230,7 +229,7 @@
         .cloned()
         .collect();
         let mut state_map = expected_state_map.clone();
-        let mut copymap = HashMap::new();
+        let mut copymap = FastHashMap::default();
         copymap.insert(
             HgPathBuf::from_bytes(b"f1"),
             HgPathBuf::from_bytes(b"copyname"),
@@ -270,7 +269,7 @@
         .iter()
         .cloned()
         .collect();
-        let mut copymap = HashMap::new();
+        let mut copymap = FastHashMap::default();
         copymap.insert(
             HgPathBuf::from_bytes(b"f1"),
             HgPathBuf::from_bytes(b"copyname"),
@@ -284,8 +283,8 @@
             pack_dirstate(&mut state_map, &copymap, parents.clone(), now)
                 .unwrap();
 
-        let mut new_state_map: StateMap = HashMap::new();
-        let mut new_copy_map: CopyMap = HashMap::new();
+        let mut new_state_map: StateMap = FastHashMap::default();
+        let mut new_copy_map: CopyMap = FastHashMap::default();
         let new_parents = parse_dirstate(
             &mut new_state_map,
             &mut new_copy_map,
@@ -341,7 +340,7 @@
         .iter()
         .cloned()
         .collect();
-        let mut copymap = HashMap::new();
+        let mut copymap = FastHashMap::default();
         copymap.insert(
             HgPathBuf::from_bytes(b"f1"),
             HgPathBuf::from_bytes(b"copyname"),
@@ -359,8 +358,8 @@
             pack_dirstate(&mut state_map, &copymap, parents.clone(), now)
                 .unwrap();
 
-        let mut new_state_map: StateMap = HashMap::new();
-        let mut new_copy_map: CopyMap = HashMap::new();
+        let mut new_state_map: StateMap = FastHashMap::default();
+        let mut new_copy_map: CopyMap = FastHashMap::default();
         let new_parents = parse_dirstate(
             &mut new_state_map,
             &mut new_copy_map,
@@ -388,7 +387,7 @@
         .iter()
         .cloned()
         .collect();
-        let mut copymap = HashMap::new();
+        let mut copymap = FastHashMap::default();
         copymap.insert(
             HgPathBuf::from_bytes(b"f1"),
             HgPathBuf::from_bytes(b"copyname"),
@@ -402,8 +401,8 @@
             pack_dirstate(&mut state_map, &copymap, parents.clone(), now)
                 .unwrap();
 
-        let mut new_state_map: StateMap = HashMap::new();
-        let mut new_copy_map: CopyMap = HashMap::new();
+        let mut new_state_map: StateMap = FastHashMap::default();
+        let mut new_copy_map: CopyMap = FastHashMap::default();
         let new_parents = parse_dirstate(
             &mut new_state_map,
             &mut new_copy_map,

--- a/rust/hg-core/src/discovery.rs	Mon Dec 02 14:44:26 2019 +0100
+++ b/rust/hg-core/src/discovery.rs	Mon Oct 14 13:57:30 2019 +0200
@@ -11,12 +11,11 @@
 //! `mercurial.setdiscovery`
 
 use super::{Graph, GraphError, Revision, NULL_REVISION};
-use crate::ancestors::MissingAncestors;
-use crate::dagops;
+use crate::{ancestors::MissingAncestors, dagops, FastHashMap};
 use rand::seq::SliceRandom;
 use rand::{thread_rng, RngCore, SeedableRng};
 use std::cmp::{max, min};
-use std::collections::{HashMap, HashSet, VecDeque};
+use std::collections::{HashSet, VecDeque};
 
 type Rng = rand_pcg::Pcg32;
 
@@ -25,7 +24,7 @@
     graph: G, // plays the role of self._repo
     common: MissingAncestors<G>,
     undecided: Option<HashSet<Revision>>,
-    children_cache: Option<HashMap<Revision, Vec<Revision>>>,
+    children_cache: Option<FastHashMap<Revision, Vec<Revision>>>,
     missing: HashSet<Revision>,
     rng: Rng,
     respect_size: bool,
@@ -61,7 +60,7 @@
 where
     I: Iterator<Item = Revision>,
 {
-    let mut distances: HashMap<Revision, u32> = HashMap::new();
+    let mut distances: FastHashMap<Revision, u32> = FastHashMap::default();
     let mut visit: VecDeque<Revision> = heads.into_iter().collect();
     let mut factor: u32 = 1;
     let mut seen: HashSet<Revision> = HashSet::new();
@@ -328,7 +327,8 @@
         }
         self.ensure_undecided()?;
 
-        let mut children: HashMap<Revision, Vec<Revision>> = HashMap::new();
+        let mut children: FastHashMap<Revision, Vec<Revision>> =
+            FastHashMap::default();
         for &rev in self.undecided.as_ref().unwrap() {
             for p in ParentsIterator::graph_parents(&self.graph, rev)? {
                 children.entry(p).or_insert_with(|| Vec::new()).push(rev);

--- a/rust/hg-core/src/filepatterns.rs	Mon Dec 02 14:44:26 2019 +0100
+++ b/rust/hg-core/src/filepatterns.rs	Mon Oct 14 13:57:30 2019 +0200
@@ -7,10 +7,11 @@
 
 //! Handling of Mercurial-specific patterns.
 
-use crate::{utils::SliceExt, LineNumber, PatternError, PatternFileError};
+use crate::{
+    utils::SliceExt, FastHashMap, LineNumber, PatternError, PatternFileError,
+};
 use lazy_static::lazy_static;
 use regex::bytes::{NoExpand, Regex};
-use std::collections::HashMap;
 use std::fs::File;
 use std::io::Read;
 use std::path::{Path, PathBuf};
@@ -214,8 +215,8 @@
 }
 
 lazy_static! {
-    static ref SYNTAXES: HashMap<&'static [u8], &'static [u8]> = {
-        let mut m = HashMap::new();
+    static ref SYNTAXES: FastHashMap<&'static [u8], &'static [u8]> = {
+        let mut m = FastHashMap::default();
 
         m.insert(b"re".as_ref(), b"relre:".as_ref());
         m.insert(b"regexp".as_ref(), b"relre:".as_ref());

--- a/rust/hg-core/src/lib.rs	Mon Dec 02 14:44:26 2019 +0100
+++ b/rust/hg-core/src/lib.rs	Mon Oct 14 13:57:30 2019 +0200
@@ -24,6 +24,8 @@
 pub use filepatterns::{
     build_single_regex, read_pattern_file, PatternSyntax, PatternTuple,
 };
+use std::collections::HashMap;
+use twox_hash::RandomXxHashBuilder64;
 
 /// Mercurial revision numbers
 ///
@@ -53,6 +55,11 @@
 
 pub type LineNumber = usize;
 
+/// Rust's default hasher is too slow because it tries to prevent collision
+/// attacks. We are not concerned about those: if an ill-minded person has
+/// write access to your repository, you have other issues.
+pub type FastHashMap<K, V> = HashMap<K, V, RandomXxHashBuilder64>;
+
 #[derive(Clone, Debug, PartialEq)]
 pub enum GraphError {
     ParentOutOfRange(Revision),

--- a/rust/hg-cpython/src/parsers.rs	Mon Dec 02 14:44:26 2019 +0100
+++ b/rust/hg-cpython/src/parsers.rs	Mon Oct 14 13:57:30 2019 +0200
@@ -15,9 +15,9 @@
 };
 use hg::{
     pack_dirstate, parse_dirstate, utils::hg_path::HgPathBuf,
-    DirstatePackError, DirstateParents, DirstateParseError, PARENT_SIZE,
+    DirstatePackError, DirstateParents, DirstateParseError, FastHashMap,
+    PARENT_SIZE,
 };
-use std::collections::HashMap;
 use std::convert::TryInto;
 
 use crate::dirstate::{extract_dirstate, make_dirstate_tuple};
@@ -29,8 +29,8 @@
     copymap: PyDict,
     st: PyBytes,
 ) -> PyResult<PyTuple> {
-    let mut dirstate_map = HashMap::new();
-    let mut copies = HashMap::new();
+    let mut dirstate_map = FastHashMap::default();
+    let mut copies = FastHashMap::default();
 
     match parse_dirstate(&mut dirstate_map, &mut copies, st.data(py)) {
         Ok(parents) => {
@@ -85,7 +85,7 @@
 
     let mut dirstate_map = extract_dirstate(py, &dmap)?;
 
-    let copies: Result<HashMap<HgPathBuf, HgPathBuf>, PyErr> = copymap
+    let copies: Result<FastHashMap<HgPathBuf, HgPathBuf>, PyErr> = copymap
         .items(py)
         .iter()
         .map(|(key, value)| {