D7116: rust-performance: introduce FastHashMap type alias for HashMap

Closed by commit rHG5ac243a92e37: rust-performance: introduce FastHashMap type alias for HashMap (authored by Alphare). This revision was automatically updated to reflect the committed changes. This revision was not accepted when it landed; it landed in state "Needs Review". REPOSITORY rHG

D7116: rust-performance: introduce FastHashMap type alias for HashMap

Alphare updated this revision to Diff 18563. REPOSITORY rHG Mercurial CHANGES SINCE LAST UPDATE https://phab.mercurial-scm.org/D7116?vs=18039=18563 BRANCH default CHANGES SINCE LAST ACTION https://phab.mercurial-scm.org/D7116/new/ REVISION DETAIL https://phab.mercurial-scm.org/D7116

D7116: rust-performance: introduce FastHashMap type alias for HashMap

marmoute added a comment. Any update on this ? I'll need it for my work on copy tracing. Reading the review thread, there is no remaining blocker to land this. REPOSITORY rHG Mercurial CHANGES SINCE LAST ACTION https://phab.mercurial-scm.org/D7116/new/ REVISION DETAIL

D7116: rust-performance: introduce FastHashMap type alias for HashMap

Alphare updated this revision to Diff 18039. REPOSITORY rHG Mercurial CHANGES SINCE LAST UPDATE https://phab.mercurial-scm.org/D7116?vs=17198=18039 BRANCH default CHANGES SINCE LAST ACTION https://phab.mercurial-scm.org/D7116/new/ REVISION DETAIL https://phab.mercurial-scm.org/D7116

D7116: rust-performance: introduce FastHashMap type alias for HashMap

This revision now requires changes to proceed. durin42 added a comment. durin42 requested changes to this revision. It sounds like I expect this to be rebased now that other patches landed. Let me know if that's wrong? REPOSITORY rHG Mercurial CHANGES SINCE LAST ACTION

D7116: rust-performance: introduce FastHashMap type alias for HashMap

Alphare added a comment. I'll rebase this series once my other patches land, to make it easier to get all instances of `HashMap` in the codebase. REPOSITORY rHG Mercurial CHANGES SINCE LAST ACTION https://phab.mercurial-scm.org/D7116/new/ REVISION DETAIL

D7116: rust-performance: introduce FastHashMap type alias for HashMap

kevincox added a comment. In D7116#104769 , @Alphare wrote: > The following comparison shows that for input > 20 bytes, fnv has worse overall performance than xx Sounds good. We can always do benchmarks in the future and swap it.

D7116: rust-performance: introduce FastHashMap type alias for HashMap

Alphare added a comment. In D7116#104685 , @kevincox wrote: > I've seen very good results with https://github.com/servo/rust-fnv in the past so it is probably worth including that in the comparison and possibly using it. It is especially

D7116: rust-performance: introduce FastHashMap type alias for HashMap

kevincox added a comment. kevincox accepted this revision. I've seen very good results with https://github.com/servo/rust-fnv in the past so it is probably worth including that in the comparison and possibly using it. It is especially good for small keys which seems like a common case in

D7116: rust-performance: introduce FastHashMap type alias for HashMap

kevincox added a comment. In D7116#104617 , @durin42 wrote: > OOC, have you compared this with the hashbrown crate for perf? std::collections::HashMap now uses hashbrown https://blog.rust-lang.org/2019/07/04/Rust-1.36.0.html REPOSITORY

D7116: rust-performance: introduce FastHashMap type alias for HashMap

durin42 added a comment. OOC, have you compared this with the hashbrown crate for perf? REPOSITORY rHG Mercurial CHANGES SINCE LAST ACTION https://phab.mercurial-scm.org/D7116/new/ REVISION DETAIL https://phab.mercurial-scm.org/D7116 To: Alphare, #hg-reviewers Cc: durin42, kevincox,

D7116: rust-performance: introduce FastHashMap type alias for HashMap

Alphare created this revision. Herald added subscribers: mercurial-devel, kevincox, durin42. Herald added a reviewer: hg-reviewers. REVISION SUMMARY Rust's default hashing is slow, because it is meant for preventing collision attacks. For all of the current Rust code, we don't care about