Auto merge of #75257 - ssomers:btree_74762_again, r=Mark-Simulacrum
BTreeMap: better way to postpone root access in DrainFilter A slightly more elegant (in my opinion) adaptation of #74762. Benchmarks seem irrationally pleased to: ``` benchcmp old new --threshold 5 name old ns/iter new ns/iter diff ns/iter diff % speedup btree::map::clone_fat_100_and_remove_all 215,182 185,052 -30,130 -14.00% x 1.16 btree::map::clone_fat_100_and_remove_half 139,667 127,945 -11,722 -8.39% x 1.09 btree::map::clone_fat_val_100_and_remove_all 96,755 81,279 -15,476 -16.00% x 1.19 btree::map::clone_fat_val_100_and_remove_half 64,678 56,911 -7,767 -12.01% x 1.14 btree::map::find_rand_100 18 17 -1 -5.56% x 1.06 btree::map::first_and_last_0 33 35 2 6.06% x 0.94 btree::map::first_and_last_100 40 54 14 35.00% x 0.74 btree::map::insert_rand_100 45 42 -3 -6.67% x 1.07 btree::map::insert_rand_10_000 45 41 -4 -8.89% x 1.10 btree::map::iter_0 2,010 1,759 -251 -12.49% x 1.14 btree::map::iter_100 3,514 2,764 -750 -21.34% x 1.27 btree::map::iter_10k 4,018 3,768 -250 -6.22% x 1.07 btree::map::range_unbounded_unbounded 37,269 28,929 -8,340 -22.38% x 1.29 btree::map::range_unbounded_vs_iter 31,518 28,814 -2,704 -8.58% x 1.09 ``` r? @Mark-Simulacrum
This commit is contained in:
bors
commit
d19d7e2755
@ -1697,10 +1697,9 @@ impl<'a, K: 'a, V: 'a> DrainFilterInner<'a, K, V> {
|
||||
let (k, v) = kv.kv_mut();
|
||||
if pred(k, v) {
|
||||
*self.length -= 1;
|
||||
let RemoveResult { old_kv, pos, emptied_internal_root } = kv.remove_kv_tracking();
|
||||
let (kv, pos) = kv.remove_kv_tracking(|_| self.emptied_internal_root = true);
|
||||
self.cur_leaf_edge = Some(pos);
|
||||
self.emptied_internal_root |= emptied_internal_root;
|
||||
return Some(old_kv);
|
||||
return Some(kv);
|
||||
}
|
||||
self.cur_leaf_edge = Some(kv.next_leaf_edge());
|
||||
}
|
||||
@ -2645,35 +2644,28 @@ impl<'a, K: Ord, V> OccupiedEntry<'a, K, V> {
|
||||
fn remove_kv(self) -> (K, V) {
|
||||
*self.length -= 1;
|
||||
|
||||
let RemoveResult { old_kv, pos, emptied_internal_root } = self.handle.remove_kv_tracking();
|
||||
let root = pos.into_node().into_root_mut();
|
||||
if emptied_internal_root {
|
||||
root.pop_internal_level();
|
||||
}
|
||||
let (old_kv, _) =
|
||||
self.handle.remove_kv_tracking(|root| root.into_root_mut().pop_internal_level());
|
||||
old_kv
|
||||
}
|
||||
}
|
||||
|
||||
struct RemoveResult<'a, K, V> {
|
||||
// Key and value removed.
|
||||
old_kv: (K, V),
|
||||
// Unique location at the leaf level that the removed KV lopgically collapsed into.
|
||||
pos: Handle<NodeRef<marker::Mut<'a>, K, V, marker::Leaf>, marker::Edge>,
|
||||
// Whether the remove left behind and empty internal root node, that should be removed
|
||||
// using `pop_internal_level`.
|
||||
emptied_internal_root: bool,
|
||||
}
|
||||
|
||||
impl<'a, K: 'a, V: 'a> Handle<NodeRef<marker::Mut<'a>, K, V, marker::LeafOrInternal>, marker::KV> {
|
||||
/// Removes a key/value-pair from the tree, and returns that pair, as well as
|
||||
/// the leaf edge corresponding to that former pair. It's possible this leaves
|
||||
/// an empty internal root node, which the caller should subsequently pop from
|
||||
/// the map holding the tree. The caller should also decrement the map's length.
|
||||
fn remove_kv_tracking(self) -> RemoveResult<'a, K, V> {
|
||||
let (mut pos, old_key, old_val, was_internal) = match self.force() {
|
||||
fn remove_kv_tracking<F>(
|
||||
self,
|
||||
handle_emptied_internal_root: F,
|
||||
) -> ((K, V), Handle<NodeRef<marker::Mut<'a>, K, V, marker::Leaf>, marker::Edge>)
|
||||
where
|
||||
F: FnOnce(NodeRef<marker::Mut<'a>, K, V, marker::Internal>),
|
||||
{
|
||||
let (old_kv, mut pos, was_internal) = match self.force() {
|
||||
Leaf(leaf) => {
|
||||
let (hole, old_key, old_val) = leaf.remove();
|
||||
(hole, old_key, old_val, false)
|
||||
let (old_kv, pos) = leaf.remove();
|
||||
(old_kv, pos, false)
|
||||
}
|
||||
Internal(mut internal) => {
|
||||
// Replace the location freed in the internal node with the next KV,
|
||||
@ -2688,17 +2680,16 @@ impl<'a, K: 'a, V: 'a> Handle<NodeRef<marker::Mut<'a>, K, V, marker::LeafOrInter
|
||||
let to_remove = internal.left_edge().descend().last_leaf_edge().left_kv().ok();
|
||||
let to_remove = unsafe { unwrap_unchecked(to_remove) };
|
||||
|
||||
let (hole, key, val) = to_remove.remove();
|
||||
let (kv, pos) = to_remove.remove();
|
||||
|
||||
let old_key = unsafe { mem::replace(&mut *key_loc, key) };
|
||||
let old_val = unsafe { mem::replace(&mut *val_loc, val) };
|
||||
let old_key = unsafe { mem::replace(&mut *key_loc, kv.0) };
|
||||
let old_val = unsafe { mem::replace(&mut *val_loc, kv.1) };
|
||||
|
||||
(hole, old_key, old_val, true)
|
||||
((old_key, old_val), pos, true)
|
||||
}
|
||||
};
|
||||
|
||||
// Handle underflow
|
||||
let mut emptied_internal_root = false;
|
||||
let mut cur_node = unsafe { ptr::read(&pos).into_node().forget_type() };
|
||||
let mut at_leaf = true;
|
||||
while cur_node.len() < node::MIN_LEN {
|
||||
@ -2719,8 +2710,10 @@ impl<'a, K: 'a, V: 'a> Handle<NodeRef<marker::Mut<'a>, K, V, marker::LeafOrInter
|
||||
|
||||
let parent = edge.into_node();
|
||||
if parent.len() == 0 {
|
||||
// This empty parent must be the root, and should be popped off the tree.
|
||||
emptied_internal_root = true;
|
||||
// The parent that was just emptied must be the root,
|
||||
// because nodes on a lower level would not have been
|
||||
// left underfull. It has to be popped off the tree soon.
|
||||
handle_emptied_internal_root(parent);
|
||||
break;
|
||||
} else {
|
||||
cur_node = parent.forget_type();
|
||||
@ -2747,7 +2740,7 @@ impl<'a, K: 'a, V: 'a> Handle<NodeRef<marker::Mut<'a>, K, V, marker::LeafOrInter
|
||||
pos = unsafe { unwrap_unchecked(pos.next_kv().ok()).next_leaf_edge() };
|
||||
}
|
||||
|
||||
RemoveResult { old_kv: (old_key, old_val), pos, emptied_internal_root }
|
||||
(old_kv, pos)
|
||||
}
|
||||
}
|
||||
|
||||
|
||||
@ -1083,12 +1083,12 @@ impl<'a, K, V> Handle<NodeRef<marker::Mut<'a>, K, V, marker::Leaf>, marker::KV>
|
||||
/// between the now adjacent key/value pairs (if any) to the left and right of this handle.
|
||||
pub fn remove(
|
||||
mut self,
|
||||
) -> (Handle<NodeRef<marker::Mut<'a>, K, V, marker::Leaf>, marker::Edge>, K, V) {
|
||||
) -> ((K, V), Handle<NodeRef<marker::Mut<'a>, K, V, marker::Leaf>, marker::Edge>) {
|
||||
unsafe {
|
||||
let k = slice_remove(self.node.keys_mut(), self.idx);
|
||||
let v = slice_remove(self.node.vals_mut(), self.idx);
|
||||
(*self.node.as_leaf_mut()).len -= 1;
|
||||
(self.left_edge(), k, v)
|
||||
((k, v), self.left_edge())
|
||||
}
|
||||
}
|
||||
}
|
||||
|
||||
Loading…
x
Reference in New Issue
Block a user