通过使用transient map提高cljs.core/distinct性能

Question

当前实现的cljs.core/distinct使用持久化集合。此补丁通过使用transient map代替，提高了性能，大致提升了10%-33%。反映Clojure任务CLJ-2090。


10个元素
(reduce + 0 (distinct coll))     12.360220502805724 µs => 9.504153281757874 µs (-23%)
(transduce (distinct) + 0 coll)  7.689213711227641 µs => 5.3549045227207 µs (-30%)
100个元素
(reduce + 0 (distinct coll))     136.43424283765356 µs => 106.66990187713321 µs (-21%)
(transduce (distinct) + 0 coll)  73.05427319211107 µs => 48.737280701754386 µs (-33%)
1000个元素
(reduce + 0 (distinct coll))     1.1207102908277415 ms => 919.8952205882359 µs (-17%)
(transduce (distinct) + 0 coll)  677.2834912043312 µs => 482.79681467181547 µs (-28%)
10000个元素
(reduce + 0 (distinct coll))     4.777295238095228 ms => 4.3203448275862115 ms (-9%)
(transduce (distinct) + 0 coll)  2.889020114942531 ms => 2.44890487804879 ms (-15%)


基准测试代码： https://gist.github.com/tonsky/258c3d715e6a485522f7ba5e663624fd

Answer 1

评论者：mfikes

修正后的 Claus-1881-transitional-in-distinct .patch 不再适用

Answer 2

参考：https://clojure.atlassian.net/browse/CLJS-1881（由 tonsky 报告）