Use Gecko's simpler Bloom filter instead of one based on hash

stretching.

This preserves the usage of the Bloom filter throughout style recalc,
but the implementation is rewritten. Provides a 15% improvement on
Guardians of the Galaxy.
This commit is contained in:
Patrick Walton 2014-09-16 22:58:52 -07:00
parent 878ece58da
commit 2a790d06dd
10 changed files with 335 additions and 357 deletions

View file

@ -13,11 +13,10 @@ use flow;
use incremental::RestyleDamage;
use wrapper::{layout_node_to_unsafe_layout_node, LayoutNode};
use wrapper::{PostorderNodeMutTraversal, ThreadSafeLayoutNode, UnsafeLayoutNode};
use wrapper::{PreorderDOMTraversal, PostorderDOMTraversal};
use wrapper::{PreorderDomTraversal, PostorderDomTraversal};
use servo_util::bloom::BloomFilter;
use servo_util::tid::tid;
use style;
use style::TNode;
/// Every time we do another layout, the old bloom filters are invalid. This is
@ -44,48 +43,47 @@ type Generation = uint;
/// Since a work-stealing queue is used for styling, sometimes, the bloom filter
/// will no longer be the for the parent of the node we're currently on. When
/// this happens, the task local bloom filter will be thrown away and rebuilt.
local_data_key!(style_bloom: (BloomFilter, UnsafeLayoutNode, Generation))
local_data_key!(style_bloom: (Box<BloomFilter>, UnsafeLayoutNode, Generation))
/// Returns the task local bloom filter.
///
/// If one does not exist, a new one will be made for you. If it is out of date,
/// it will be thrown out and a new one will be made for you.
fn take_task_local_bloom_filter(
parent_node: Option<LayoutNode>,
layout_context: &LayoutContext)
-> BloomFilter {
let new_bloom =
|p: Option<LayoutNode>| -> BloomFilter {
let mut bf = BloomFilter::new(style::RECOMMENDED_SELECTOR_BLOOM_FILTER_SIZE);
p.map(|p| insert_ancestors_into_bloom_filter(&mut bf, p, layout_context));
if p.is_none() {
debug!("[{}] No parent, but new bloom filter!", tid());
}
bf
};
fn take_task_local_bloom_filter(parent_node: Option<LayoutNode>, layout_context: &LayoutContext)
-> Box<BloomFilter> {
match (parent_node, style_bloom.replace(None)) {
// Root node. Needs new bloom filter.
(None, _ ) => new_bloom(None),
(None, _ ) => {
debug!("[{}] No parent, but new bloom filter!", tid());
box BloomFilter::new()
}
// No bloom filter for this thread yet.
(Some(p), None) => new_bloom(Some(p)),
(Some(parent), None) => {
let mut bloom_filter = box BloomFilter::new();
insert_ancestors_into_bloom_filter(&mut bloom_filter, parent, layout_context);
bloom_filter
}
// Found cached bloom filter.
(Some(p), Some((bf, old_node, old_generation))) => {
(Some(parent), Some((mut bloom_filter, old_node, old_generation))) => {
// Hey, the cached parent is our parent! We can reuse the bloom filter.
if old_node == layout_node_to_unsafe_layout_node(&p) &&
if old_node == layout_node_to_unsafe_layout_node(&parent) &&
old_generation == layout_context.shared.generation {
debug!("[{}] Parent matches (={}). Reusing bloom filter.", tid(), old_node.val0());
bf
// Oh no. the cached parent is stale. I guess we need a new one...
bloom_filter
} else {
new_bloom(Some(p))
// Oh no. the cached parent is stale. I guess we need a new one. Reuse the existing
// allocation to avoid malloc churn.
*bloom_filter = BloomFilter::new();
insert_ancestors_into_bloom_filter(&mut bloom_filter, parent, layout_context);
bloom_filter
}
},
}
}
fn put_task_local_bloom_filter(bf: BloomFilter, unsafe_node: &UnsafeLayoutNode, layout_context: &LayoutContext) {
fn put_task_local_bloom_filter(bf: Box<BloomFilter>,
unsafe_node: &UnsafeLayoutNode,
layout_context: &LayoutContext) {
match style_bloom.replace(Some((bf, *unsafe_node, layout_context.shared.generation))) {
None => {},
Some(_) => fail!("Putting into a never-taken task-local bloom filter"),
@ -93,14 +91,15 @@ fn put_task_local_bloom_filter(bf: BloomFilter, unsafe_node: &UnsafeLayoutNode,
}
/// "Ancestors" in this context is inclusive of ourselves.
fn insert_ancestors_into_bloom_filter(
bf: &mut BloomFilter, mut n: LayoutNode, layout_context: &LayoutContext) {
fn insert_ancestors_into_bloom_filter(bf: &mut Box<BloomFilter>,
mut n: LayoutNode,
layout_context: &LayoutContext) {
debug!("[{}] Inserting ancestors.", tid());
let mut ancestors = 0u;
loop {
ancestors += 1;
n.insert_into_bloom_filter(bf);
n.insert_into_bloom_filter(&mut **bf);
n = match n.layout_parent_node(layout_context.shared) {
None => break,
Some(p) => p,
@ -115,7 +114,7 @@ pub struct RecalcStyleForNode<'a> {
pub layout_context: &'a LayoutContext<'a>,
}
impl<'a> PreorderDOMTraversal for RecalcStyleForNode<'a> {
impl<'a> PreorderDomTraversal for RecalcStyleForNode<'a> {
#[inline]
fn process(&self, node: LayoutNode) {
// Initialize layout data.
@ -135,7 +134,8 @@ impl<'a> PreorderDOMTraversal for RecalcStyleForNode<'a> {
if node.is_dirty() {
// First, check to see whether we can share a style with someone.
let style_sharing_candidate_cache = self.layout_context.style_sharing_candidate_cache();
let style_sharing_candidate_cache =
self.layout_context.style_sharing_candidate_cache();
let sharing_result = unsafe {
node.share_style_if_possible(style_sharing_candidate_cache,
parent_opt.clone())
@ -148,8 +148,11 @@ impl<'a> PreorderDOMTraversal for RecalcStyleForNode<'a> {
if node.is_element() {
// Perform the CSS selector matching.
let stylist = unsafe { &*self.layout_context.shared.stylist };
node.match_node(stylist, &some_bf, &mut applicable_declarations, &mut shareable);
}
node.match_node(stylist,
&some_bf,
&mut applicable_declarations,
&mut shareable);
}
// Perform the CSS cascade.
unsafe {
@ -174,7 +177,7 @@ impl<'a> PreorderDOMTraversal for RecalcStyleForNode<'a> {
// Before running the children, we need to insert our nodes into the bloom
// filter.
debug!("[{}] + {:X}", tid(), unsafe_layout_node.val0());
node.insert_into_bloom_filter(&mut bf);
node.insert_into_bloom_filter(&mut *bf);
// NB: flow construction updates the bloom filter on the way up.
put_task_local_bloom_filter(bf, &unsafe_layout_node, self.layout_context);
@ -186,7 +189,7 @@ pub struct ConstructFlows<'a> {
pub layout_context: &'a LayoutContext<'a>,
}
impl<'a> PostorderDOMTraversal for ConstructFlows<'a> {
impl<'a> PostorderDomTraversal for ConstructFlows<'a> {
#[inline]
fn process(&self, node: LayoutNode) {
// Construct flows for this node.
@ -222,7 +225,7 @@ impl<'a> PostorderDOMTraversal for ConstructFlows<'a> {
}
Some(parent) => {
// Otherwise, put it back, but remove this node.
node.remove_from_bloom_filter(&mut bf);
node.remove_from_bloom_filter(&mut *bf);
let unsafe_parent = layout_node_to_unsafe_layout_node(&parent);
put_task_local_bloom_filter(bf, &unsafe_parent, self.layout_context);
},
@ -248,8 +251,8 @@ impl PreorderFlow for FlowTreeVerification {
}
}
/// The bubble-inline-sizes traversal, the first part of layout computation. This computes preferred
/// and intrinsic inline-sizes and bubbles them up the tree.
/// The bubble-inline-sizes traversal, the first part of layout computation. This computes
/// preferred and intrinsic inline-sizes and bubbles them up the tree.
pub struct BubbleISizes<'a> {
pub layout_context: &'a LayoutContext<'a>,
}
@ -283,9 +286,10 @@ impl<'a> PreorderFlowTraversal for AssignISizes<'a> {
}
}
/// The assign-block-sizes-and-store-overflow traversal, the last (and most expensive) part of layout
/// computation. Determines the final block-sizes for all layout objects, computes positions, and
/// computes overflow regions. In Gecko this corresponds to `FinishAndStoreOverflow`.
/// The assign-block-sizes-and-store-overflow traversal, the last (and most expensive) part of
/// layout computation. Determines the final block-sizes for all layout objects, computes
/// positions, and computes overflow regions. In Gecko this corresponds to `Reflow` and
/// `FinishAndStoreOverflow`.
pub struct AssignBSizesAndStoreOverflow<'a> {
pub layout_context: &'a LayoutContext<'a>,
}