0.4.0 (#16)

* add run_deferred calls after all test cases

additionally, run_deferred now allocates a pretty massive amount of
memory in the hopes of filling up the thread and global caches. it seems
to work pretty reliably, but it would be better if crossbeam-epoch
exposed an API for directly clearing out the thread and global caches.

* update copyright year in LICENSE to 2020

* add StripedHashMap (#14)

* move all HashMap code of note into BucketArrayRef

BucketArrayRef abstracts away the necessary parts of a hash map behind
references. This will make implementing the striped table extremely
easy!

* add striped::map::HashMap, alias as StripedHashMap

StripedHashMap partitions a hash map into submaps, where each submap is
allocated separately. This is an effort to further spread entries around
in memory and reduce contention.

* impl Drop for striped::map::HashMap

whoops!

* add #[inline] to all important table operations

all of these just dispatch out to another member function or to a
BucketArrayRef function. kind of wasteful to not inline them!

* reorder arguments to StripedHashMap constructors

to match the names of the functions

* correct feature names

* memset+Vec::set_len to write a lot of Shared::null

this provides a measurable boost to the performance of functions like
with_capacity. yes, unsafe, but also yes, really fast.

* double default minimum stripe amount

empirically provides the best performance

* reorganize tests into an icky macro invocation

* bump version to 0.4.0

* refer to segments as segments, not stripes

in the context of a hash table, striping refers to using a (relatively)
small set of locks per bucket. segmenting, the correct term, refers to
composing a large hash map out of several smaller hash maps (segments).

Cargo.toml

@@ -1,16 +1,21 @@
 [package]
 name = "cht"
-version = "0.3.0"
+version = "0.4.0"
 authors = ["Gregory Meyer <[email protected]>"]
 edition = "2018"
 description = "Lockfree resizeable concurrent hash table."
 repository = "https://github.com/Gregory-Meyer/cht"
 readme = "README.md"
 license = "MIT"
 
+[features]
+default = ["num-cpus"]
+num-cpus = ["num_cpus"]
+
 [dependencies]
 ahash = "^0.3.2"
 crossbeam-epoch = "^0.8.2"
+num_cpus = { version = "^1.12.0", optional = true }
 
 [dev-dependencies]
 criterion = "^0.3.1"

LICENSE

@@ -1,6 +1,6 @@
 MIT License
 
-Copyright (c) 2019 Gregory Meyer
+Copyright (c) 2020 Gregory Meyer
 
 Permission is hereby granted, free of charge, to any person obtaining a copy
 of this software and associated documentation files (the "Software"), to deal

src/lib.rs

@@ -32,5 +32,11 @@
 //! [Junction]: https://github.com/preshing/junction
 
 pub mod map;
+pub mod segment;
+
+#[cfg(test)]
+#[macro_use]
+pub(crate) mod test_util;
 
 pub use map::HashMap;
+pub use segment::HashMap as SegmentedHashMap;