Mercurial > public > mercurial-scm > hg
view rust/hg-core/src/lib.rs @ 47119:15395fd8ab28
dirstate-tree: Use HashMap instead of BTreeMap
BTreeMap has the advantage of its "natural" iteration order being the one we need
in the status algorithm. With HashMap however, iteration order is undefined so
we need to allocate a Vec and sort it explicitly.
Unfortunately many BTreeMap operations are slower than in HashMap, and skipping
that extra allocation and sort is not enough to compensate.
Switching to HashMap + sort makes `hg status` 17% faster in one test case,
as measure with hyperfine:
```
Benchmark #1: ../hg2/hg status -R $REPO --config=experimental.dirstate-tree.in-memory=1
Time (mean ? ?): 765.0 ms ? 8.8 ms [User: 1.352 s, System: 0.747 s]
Range (min ? max): 751.8 ms ? 778.7 ms 10 runs
Benchmark #2: ./hg status -R $REPO --config=experimental.dirstate-tree.in-memory=1
Time (mean ? ?): 651.8 ms ? 9.9 ms [User: 1.251 s, System: 0.799 s]
Range (min ? max): 642.2 ms ? 671.8 ms 10 runs
Summary
'./hg status -R $REPO --config=experimental.dirstate-tree.in-memory=1' ran
1.17 ? 0.02 times faster than '../hg2/hg status -R $REPO --config=experimental.dirstate-tree.in-memory=1'
```
* ./hg is this revision
* ../hg2/hg is its parent
* $REPO is an old snapshot of mozilla-central
Differential Revision: https://phab.mercurial-scm.org/D10553
author | Simon Sapin <simon.sapin@octobus.net> |
---|---|
date | Thu, 29 Apr 2021 11:32:57 +0200 |
parents | 5d62243c7732 |
children | ed1583a845d2 |
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// Copyright 2018-2020 Georges Racinet <georges.racinet@octobus.net> // and Mercurial contributors // // This software may be used and distributed according to the terms of the // GNU General Public License version 2 or any later version. mod ancestors; pub mod dagops; pub mod errors; pub use ancestors::{AncestorsIterator, LazyAncestors, MissingAncestors}; pub mod dirstate; pub mod dirstate_tree; pub mod discovery; pub mod requirements; pub mod testing; // unconditionally built, for use from integration tests pub use dirstate::{ dirs_multiset::{DirsMultiset, DirsMultisetIter}, dirstate_map::DirstateMap, parsers::{pack_dirstate, parse_dirstate, PARENT_SIZE}, status::{ status, BadMatch, BadType, DirstateStatus, HgPathCow, StatusError, StatusOptions, }, CopyMap, CopyMapIter, DirstateEntry, DirstateParents, EntryState, StateMap, StateMapIter, }; pub mod copy_tracing; mod filepatterns; pub mod matchers; pub mod repo; pub mod revlog; pub use revlog::*; pub mod config; pub mod logging; pub mod operations; pub mod revset; pub mod utils; use crate::utils::hg_path::{HgPathBuf, HgPathError}; pub use filepatterns::{ parse_pattern_syntax, read_pattern_file, IgnorePattern, PatternFileWarning, PatternSyntax, }; use std::collections::HashMap; use std::fmt; use twox_hash::RandomXxHashBuilder64; /// This is a contract between the `micro-timer` crate and us, to expose /// the `log` crate as `crate::log`. use log; 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(Debug, PartialEq)] pub enum DirstateMapError { PathNotFound(HgPathBuf), EmptyPath, InvalidPath(HgPathError), } impl fmt::Display for DirstateMapError { fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result { match self { DirstateMapError::PathNotFound(_) => { f.write_str("expected a value, found none") } DirstateMapError::EmptyPath => { f.write_str("Overflow in dirstate.") } DirstateMapError::InvalidPath(path_error) => path_error.fmt(f), } } } #[derive(Debug, derive_more::From)] pub enum DirstateError { Map(DirstateMapError), Common(errors::HgError), } #[derive(Debug, derive_more::From)] pub enum PatternError { #[from] Path(HgPathError), UnsupportedSyntax(String), UnsupportedSyntaxInFile(String, String, usize), TooLong(usize), #[from] IO(std::io::Error), /// Needed a pattern that can be turned into a regex but got one that /// can't. This should only happen through programmer error. NonRegexPattern(IgnorePattern), } impl fmt::Display for PatternError { fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result { match self { PatternError::UnsupportedSyntax(syntax) => { write!(f, "Unsupported syntax {}", syntax) } PatternError::UnsupportedSyntaxInFile(syntax, file_path, line) => { write!( f, "{}:{}: unsupported syntax {}", file_path, line, syntax ) } PatternError::TooLong(size) => { write!(f, "matcher pattern is too long ({} bytes)", size) } PatternError::IO(error) => error.fmt(f), PatternError::Path(error) => error.fmt(f), PatternError::NonRegexPattern(pattern) => { write!(f, "'{:?}' cannot be turned into a regex", pattern) } } } }