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@arthurprs
arthurprs committed Sep 29, 2016
1 parent 2542261 commit c5250d4
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Showing 2 changed files with 116 additions and 1 deletion.
1 change: 1 addition & 0 deletions Cargo.toml
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Expand Up @@ -41,3 +41,4 @@ rand = "0.3.12"
[dev-dependencies]
fnv = "1.0"
lazy_static = "0.2"
histogram = "*"
116 changes: 115 additions & 1 deletion src/lib.rs
View file
Expand Up @@ -8,6 +8,7 @@
// option. This file may not be copied, modified, or distributed
// except according to those terms.
#![feature(
thread_local,
alloc,
core_intrinsics,
dropck_parametricity,
Expand Down Expand Up @@ -48,6 +49,14 @@ use table::BucketState::{Empty, Full};
const INITIAL_LOG2_CAP: usize = 5;
const INITIAL_CAPACITY: usize = 1 << INITIAL_LOG2_CAP; // 2^5


#[thread_local]
pub static mut _INSERT_DISPLACED: usize = 0;
#[thread_local]
pub static mut _LOOKUP_PROBED_KEYS: usize = 0;
#[thread_local]
pub static mut _LOOKUP_PROBED_HASHES: usize = 0;

/// The default behavior of HashMap implements a load factor of 90.9%.
/// This behavior is characterized by the following condition:
///
Expand Down Expand Up @@ -354,6 +363,10 @@ fn search_hashed<K, V, M, F>(table: M, hash: SafeHash, mut is_match: F) -> Inter
where M: Deref<Target = RawTable<K, V>>,
F: FnMut(&K) -> bool
{
unsafe {
_LOOKUP_PROBED_KEYS = 0;
_LOOKUP_PROBED_HASHES = 0;
}
// This is the only function where capacity can be zero. To avoid
// undefined behavior when Bucket::new gets the raw bucket in this
// case, immediately return the appropriate search result.
Expand All @@ -366,6 +379,9 @@ fn search_hashed<K, V, M, F>(table: M, hash: SafeHash, mut is_match: F) -> Inter
let ib = probe.index() as isize;

loop {
unsafe {
_LOOKUP_PROBED_HASHES += 1;
}
let full = match probe.peek() {
Empty(bucket) => {
// Found a hole!
Expand All @@ -391,6 +407,9 @@ fn search_hashed<K, V, M, F>(table: M, hash: SafeHash, mut is_match: F) -> Inter

// If the hash doesn't match, it can't be this one..
if hash == full.hash() {
unsafe {
_LOOKUP_PROBED_KEYS += 1;
}
// If the key doesn't match, it can't be this one..
if is_match(full.read().0) {
return InternalEntry::Occupied { elem: full };
Expand Down Expand Up @@ -443,7 +462,10 @@ fn robin_hood<'a, K: 'a, V: 'a>(bucket: FullBucketMut<'a, K, V>,
// `displacement` buckets away from the initial one.
let idx_end = starting_index + size - bucket.displacement();

unsafe { _INSERT_DISPLACED = 0 };

loop {
unsafe { _INSERT_DISPLACED += 1 };
let (old_hash, old_key, old_val) = bucket.replace(hash, key, val);
hash = old_hash;
key = old_key;
Expand Down Expand Up @@ -1711,7 +1733,10 @@ impl<'a, K: 'a, V: 'a> VacantEntry<'a, K, V> {
pub fn insert(self, value: V) -> &'a mut V {
match self.elem {
NeqElem(bucket, ib) => robin_hood(bucket, ib, self.hash, self.key, value),
NoElem(bucket) => bucket.put(self.hash, self.key, value).into_mut_refs().1,
NoElem(bucket) => {
unsafe { _INSERT_DISPLACED = 0 };
bucket.put(self.hash, self.key, value).into_mut_refs().1
},
}
}

Expand Down Expand Up @@ -2617,4 +2642,93 @@ mod test_map {
assert_eq!(k, "foo");
assert_eq!(v, 1);
}

#[test]
fn test_probe_lengths() {
extern crate histogram;
use super::{_LOOKUP_PROBED_HASHES, _LOOKUP_PROBED_KEYS, _INSERT_DISPLACED};

macro_rules! print_hist {
($h: ident) => (
println!("Histogram {}: Min: {:?} Avg: {:?} Max: {:?} StdDev: {:?} Median: {:?} 95pct: {:?} 99pct: {:?}",
stringify!($h),
$h.minimum(),
$h.mean(),
$h.maximum(),
$h.stddev(),
$h.percentile(50.0),
$h.percentile(95.0),
$h.percentile(99.0),
)
);
}

unsafe {
let mut hist_h = histogram::Histogram::configure().max_value(2000).precision(4).build().unwrap();
let mut hist_k = hist_h.clone();
let mut hist_d = hist_k.clone();
let n = 1_000_000;
let mut hm: HashMap<_, _> = (0..n).map(|i| (i, ())).collect();
for i in n..n*2 {
assert!(hm.insert(i, ()).is_none());
if _INSERT_DISPLACED == 0 {
_INSERT_DISPLACED = 1;
}
let _ = hist_d.increment(_INSERT_DISPLACED as u64);
}
for i in 0..n/10 {
hm.get(&i).unwrap();
let _ = hist_h.increment(_LOOKUP_PROBED_HASHES as u64);
let _ = hist_k.increment(_LOOKUP_PROBED_KEYS as u64);
}
println!("HM len {}, cap{}", hm.len(), hm.capacity());
print_hist!(hist_h);
print_hist!(hist_k);
print_hist!(hist_d);
}

unsafe {
let mut hist_h = histogram::Histogram::configure().max_value(5_000).precision(4).build().unwrap();
let mut hist_k = hist_h.clone();
let mut hist_d = hist_k.clone();
let n = 5_000_000;
let mut hm: HashMap<_, _> = (0..n).map(|i| (i, ())).collect();
for i in n..n*2 {
assert!(hm.insert(i, ()).is_none());
if _INSERT_DISPLACED == 0 {
_INSERT_DISPLACED = 1;
}
let _ = hist_d.increment(_INSERT_DISPLACED as u64);
}
for i in 0..n/10 {
hm.get(&i).unwrap();
let _ = hist_h.increment(_LOOKUP_PROBED_HASHES as u64);
let _ = hist_k.increment(_LOOKUP_PROBED_KEYS as u64);
}
println!("HM len {}, cap{}", hm.len(), hm.capacity());
print_hist!(hist_h);
print_hist!(hist_k);
print_hist!(hist_d);
}

unsafe {
let mut hist_h = histogram::Histogram::configure().max_value(10_000).precision(4).build().unwrap();
let mut hist_d = hist_h.clone();
let MERGE = 10_000;
let first_map: HashMap<_, _> = (0..MERGE).map(|i| (i, ())).collect();
let second_map: HashMap<_, _> = (MERGE..MERGE * 2).map(|i| (i, ())).collect();
let mut merged = first_map.clone();
for (k, v) in second_map {
merged.insert(k, v);
let _ = hist_h.increment(_LOOKUP_PROBED_HASHES as u64);
if _INSERT_DISPLACED == 0 {
_INSERT_DISPLACED = 1;
}
let _ = hist_d.increment(_INSERT_DISPLACED as u64);
}
println!("Merged map len {}, cap{}", merged.len(), merged.capacity());
print_hist!(hist_h);
print_hist!(hist_d);
}
}
}

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