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Convert bitwise ghost to use u64 block heights.

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Age Manning 2019-03-03 13:35:15 +11:00
parent 684ef9f74c
commit 60cfdf6e55
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2 changed files with 9 additions and 10 deletions
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18
eth2/fork_choice/src/bitwise_lmd_ghost.rs
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@ -24,22 +24,22 @@ use types::{
/// Compute the base-2 logarithm of an integer, floored (rounded down) /// Compute the base-2 logarithm of an integer, floored (rounded down)
#[inline] #[inline]
fn log2_int(x: u32) -> u32 { fn log2_int(x: u64) -> u32 {
if x == 0 { if x == 0 {
return 0; return 0;
} }
31 - x.leading_zeros() 63 - x.leading_zeros()
} }
fn power_of_2_below(x: u32) -> u32 { fn power_of_2_below(x: u64) -> u64 {
2u32.pow(log2_int(x)) 2u64.pow(log2_int(x))
} }
/// Stores the necessary data structures to run the optimised bitwise lmd ghost algorithm. /// Stores the necessary data structures to run the optimised bitwise lmd ghost algorithm.
pub struct BitwiseLMDGhost<T: ClientDB + Sized> { pub struct BitwiseLMDGhost<T: ClientDB + Sized> {
/// A cache of known ancestors at given heights for a specific block. /// A cache of known ancestors at given heights for a specific block.
//TODO: Consider FnvHashMap //TODO: Consider FnvHashMap
cache: HashMap<CacheKey<u32>, Hash256>, cache: HashMap<CacheKey<u64>, Hash256>,
/// Log lookup table for blocks to their ancestors. /// Log lookup table for blocks to their ancestors.
//TODO: Verify we only want/need a size 16 log lookup //TODO: Verify we only want/need a size 16 log lookup
ancestors: Vec<HashMap<Hash256, Hash256>>, ancestors: Vec<HashMap<Hash256, Hash256>>,
@ -141,7 +141,7 @@ where
} }
} }
// check if the result is stored in our cache // check if the result is stored in our cache
let cache_key = CacheKey::new(&block_hash, target_height.as_u32()); let cache_key = CacheKey::new(&block_hash, target_height.as_u64());
if let Some(ancestor) = self.cache.get(&cache_key) { if let Some(ancestor) = self.cache.get(&cache_key) {
return Some(*ancestor); return Some(*ancestor);
} }
@ -149,7 +149,7 @@ where
// not in the cache recursively search for ancestors using a log-lookup // not in the cache recursively search for ancestors using a log-lookup
if let Some(ancestor) = { if let Some(ancestor) = {
let ancestor_lookup = self.ancestors let ancestor_lookup = self.ancestors
[log2_int((block_height - target_height - 1u64).as_u32()) as usize] [log2_int((block_height - target_height - 1u64).as_u64()) as usize]
.get(&block_hash) .get(&block_hash)
//TODO: Panic if we can't lookup and fork choice fails //TODO: Panic if we can't lookup and fork choice fails
.expect("All blocks should be added to the ancestor log lookup table"); .expect("All blocks should be added to the ancestor log lookup table");
@ -374,7 +374,7 @@ impl<T: ClientDB + Sized> ForkChoice for BitwiseLMDGhost<T> {
// logarithmic lookup blocks to see if there are obvious winners, if so, // logarithmic lookup blocks to see if there are obvious winners, if so,
// progress to the next iteration. // progress to the next iteration.
let mut step = let mut step =
power_of_2_below(self.max_known_height.saturating_sub(block_height).as_u32()) / 2; power_of_2_below(self.max_known_height.saturating_sub(block_height).as_u64()) / 2;
while step > 0 { while step > 0 {
trace!("Current Step: {}", step); trace!("Current Step: {}", step);
if let Some(clear_winner) = self.get_clear_winner( if let Some(clear_winner) = self.get_clear_winner(
@ -474,7 +474,7 @@ mod tests {
#[test] #[test]
pub fn test_power_of_2_below_large() { pub fn test_power_of_2_below_large() {
let pow: u32 = 1 << 24; let pow: u64 = 1 << 24;
for x in (pow - 20)..(pow + 20) { for x in (pow - 20)..(pow + 20) {
assert!(power_of_2_below(x) <= x, "{}", x); assert!(power_of_2_below(x) <= x, "{}", x);
} }

1
eth2/types/src/slot_height.rs
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@ -13,7 +13,6 @@ use std::ops::{Add, AddAssign, Div, DivAssign, Mul, MulAssign, Rem, Sub, SubAssi
pub struct SlotHeight(u64); pub struct SlotHeight(u64);
impl_common!(SlotHeight); impl_common!(SlotHeight);
impl_into_u32!(SlotHeight); // SlotHeight can be converted to u32
impl SlotHeight { impl SlotHeight {
pub fn new(slot: u64) -> SlotHeight { pub fn new(slot: u64) -> SlotHeight {