https://github.com/rust-lang/rust http://git.dreamy.place/mirrors/rust/atom?h=perf-tmp 2020-07-28T00:51:13+00:00 2020-07-28T00:51:13+00:00 mark markm@cs.wisc.edu 2020-06-12T02:31:49+00:00 urn:sha1:2c31b45ae878b821975c4ebd94cc1e49f6073fd0 2020-07-24T09:56:38+00:00 Yuki Okushi huyuumi.dev@gmail.com 2020-07-24T09:56:38+00:00 urn:sha1:fab9b1d4cd5a788f46d94077b49da285ce782b74 Remove needless unsafety from BTreeMap::drain_filter Remove one piece of unsafe code in the iteration over the iterator returned by BTreeMap::drain_filter. - Changes an explicitly unspecified part of the API: when the user-supplied predicate (or some of BTreeMap's code) panicked, and the caller tries to use the iterator again, we no longer offer the same key/value pair to the predicate again but pretend the iterator has finished. Note that Miri does not find UB in the test case added here with the unsafe code (or without). - Makes the code a little easier on the eyes. - Makes the code a little harder on the CPU: ``` benchcmp c0 c2 --threshold 3 name c0 ns/iter c2 ns/iter diff ns/iter diff % speedup btree::set::clone_100_and_drain_all 2,794 2,900 106 3.79% x 0.96 btree::set::clone_100_and_drain_half 2,604 2,964 360 13.82% x 0.88 btree::set::clone_10k_and_drain_half 287,770 322,755 34,985 12.16% x 0.89 ``` r? @Amanieu 2020-07-23T16:29:07+00:00 Stein Somers git@steinsomers.be 2020-07-22T20:37:54+00:00 urn:sha1:facc46fd0a85408bc05aa19b80131e3cfb5fe3dd 2020-07-22T21:40:06+00:00 Stein Somers git@steinsomers.be 2020-07-14T09:32:50+00:00 urn:sha1:2152d18f9248d376fd43a6192888664f33dfb08d 2020-07-02T08:26:37+00:00 Ralf Jung post@ralfj.de 2020-07-02T08:25:04+00:00 urn:sha1:dca9310ceb495ae2d5c6c775c151d75202e686d7 2020-06-26T08:05:21+00:00 Stein Somers git@steinsomers.be 2020-06-22T18:12:11+00:00 urn:sha1:42062a58026cdb245e3eb365af726f2d9f4946af 2020-04-23T18:05:01+00:00 Ralf Jung post@ralfj.de 2020-04-23T18:05:01+00:00 urn:sha1:eb1de2ff39de631e9fd880f1e066fbe119b23f99 2020-04-06T21:07:38+00:00 Linus Färnstrand faern@faern.net 2020-04-06T21:07:38+00:00 urn:sha1:e4fc04b6df93785e935ec776705803e6b50e2c23 2020-03-31T22:27:18+00:00 Dylan DPC dylan.dpc@gmail.com 2020-03-31T22:27:18+00:00 urn:sha1:718ba0d23bc13cd987acbb1b2286552eeee88a1d BTreeMap/BTreeSet: implement drain_filter Provide an implementation of drain_filter for BTreeMap and BTreeSet. Should be optimal when the predicate picks only elements in leaf nodes with at least MIN_LEN remaining elements, which is a common case, at least when draining only a fraction of the map/set, and also when the predicate picks elements stored in internal nodes where the right subtree can easily let go of a replacement element. The first commit adds benchmarks with an external, naive implementation. to compare how much this claimed optimality-in-some-cases is actually worth. 2020-03-30T10:04:05+00:00 Ralf Jung post@ralfj.de 2020-03-30T10:03:55+00:00 urn:sha1:032d3cd553ec503a4483c8ef1f2a8d773775a3f2