1425770 - Compare performance of Rust's vector and hash tables against Gecko's

Status: RESOLVED WORKSFORME

(Core :: General, enhancement)

Description

[Nicholas Nethercote [inactive]]

In Q1 2018 I plan to evaluate the performance (speed and memory usage) of Rust's
basic data structures against Gecko's.

- Rust structures: Vec, HashSet and HashMap.

- Gecko structures: nsTArray, Vector, PLDHashTable and/or nsTHashtable.

The motivation is that we want to make sure that the Rust structures aren't worse. (The choice of hash function for the Rust hash tables is likely to be important -- because the default hash function is high quality but slow -- and may result in specific guidelines in the Mozilla Coding Style doc.)

Comment 1

[dalley]

FYI, there are a set of drop-in stdlib replacement HashMap and HashSet implementations available which purport to be significantly faster and consume less memory.

https://github.com/Amanieu/hashbrown

Comment 2

[dalley]

And some discussion regarding ^ https://www.reddit.com/r/rust/comments/9sn4ze/github_amanieuhashbrown_a_faster_hashmap_for_rust/

Comment 3

[Emilio Cobos Álvarez [:emilio]]

Yeah, I have a Firefox build using hashbrown in https://github.com/servo/webrender/issues/3363.

Comment 4

[Alex Gaynor [:Alex_Gaynor]]

And for good measure, some patches to make it std::collections::HashMap: https://github.com/rust-lang/rust/pull/56241

Comment 5

[Nicholas Nethercote [inactive]]

Bug 1477622 was the most important part of this, I think this bug can now be closed.