Add benchmarks

agb-hashmap/Cargo.toml

@@ -11,6 +11,7 @@ rustc-hash = { version = "1", default-features = false }
 
 [dev-dependencies]
 rand = { version = "0.8", default-features = false, features = ["small_rng"] }
+lazy_static = "1.4"
 
 [profile.dev]
 opt-level = 3

agb-hashmap/benches/bench.rs

@@ -0,0 +1,318 @@
+// These benchmarks were taken from hashbrown. They are impossible to run
+// on the target GBA hardware, but hopefully running these on something like a
+// raspberry pi zero will give something comparable.
+
+// This benchmark suite contains some benchmarks along a set of dimensions:
+//   Int key distribution: low bit heavy, top bit heavy, and random.
+//   Task: basic functionality: insert, insert_erase, lookup, lookup_fail, iter
+#![feature(test)]
+
+extern crate test;
+
+use test::{black_box, Bencher};
+
+use agb_hashmap::HashMap;
+use std::sync::atomic::{self, AtomicUsize};
+
+const SIZE: usize = 1000;
+
+type StdHashMap<K, V> = std::collections::hash_map::HashMap<K, V>;
+
+// A random key iterator.
+#[derive(Clone, Copy)]
+struct RandomKeys {
+    state: usize,
+}
+
+impl RandomKeys {
+    fn new() -> Self {
+        RandomKeys { state: 0 }
+    }
+}
+
+impl Iterator for RandomKeys {
+    type Item = usize;
+    fn next(&mut self) -> Option<usize> {
+        // Add 1 then multiply by some 32 bit prime.
+        self.state = self.state.wrapping_add(1).wrapping_mul(3_787_392_781);
+        Some(self.state)
+    }
+}
+
+// Just an arbitrary side effect to make the maps not shortcircuit to the non-dropping path
+// when dropping maps/entries (most real world usages likely have drop in the key or value)
+lazy_static::lazy_static! {
+    static ref SIDE_EFFECT: AtomicUsize = AtomicUsize::new(0);
+}
+
+#[derive(Clone)]
+struct DropType(usize);
+impl Drop for DropType {
+    fn drop(&mut self) {
+        SIDE_EFFECT.fetch_add(self.0, atomic::Ordering::SeqCst);
+    }
+}
+
+macro_rules! bench_suite {
+    ($bench_macro:ident, $bench_agb_hashmap_serial:ident, $bench_std_serial:ident,
+     $bench_agb_hashmap_highbits:ident, $bench_std_highbits:ident,
+     $bench_agb_hashmap_random:ident, $bench_std_random:ident) => {
+        $bench_macro!($bench_agb_hashmap_serial, HashMap, 0..);
+        $bench_macro!($bench_std_serial, StdHashMap, 0..);
+        $bench_macro!(
+            $bench_agb_hashmap_highbits,
+            HashMap,
+            (0..).map(usize::swap_bytes)
+        );
+        $bench_macro!(
+            $bench_std_highbits,
+            StdHashMap,
+            (0..).map(usize::swap_bytes)
+        );
+        $bench_macro!($bench_agb_hashmap_random, HashMap, RandomKeys::new());
+        $bench_macro!($bench_std_random, StdHashMap, RandomKeys::new());
+    };
+}
+
+macro_rules! bench_insert {
+    ($name:ident, $maptype:ident, $keydist:expr) => {
+        #[bench]
+        fn $name(b: &mut Bencher) {
+            let mut m = $maptype::with_capacity(SIZE);
+            b.iter(|| {
+                m.clear();
+                for i in ($keydist).take(SIZE) {
+                    m.insert(i, (DropType(i), [i; 20]));
+                }
+                black_box(&mut m);
+            });
+            eprintln!("{}", SIDE_EFFECT.load(atomic::Ordering::SeqCst));
+        }
+    };
+}
+
+bench_suite!(
+    bench_insert,
+    insert_agb_hashmap_serial,
+    insert_std_serial,
+    insert_agb_hashmap_highbits,
+    insert_std_highbits,
+    insert_agb_hashmap_random,
+    insert_std_random
+);
+
+macro_rules! bench_grow_insert {
+    ($name:ident, $maptype:ident, $keydist:expr) => {
+        #[bench]
+        fn $name(b: &mut Bencher) {
+            b.iter(|| {
+                let mut m = $maptype::default();
+                for i in ($keydist).take(SIZE) {
+                    m.insert(i, DropType(i));
+                }
+                black_box(&mut m);
+            })
+        }
+    };
+}
+
+bench_suite!(
+    bench_grow_insert,
+    grow_insert_agb_hashmap_serial,
+    grow_insert_std_serial,
+    grow_insert_agb_hashmap_highbits,
+    grow_insert_std_highbits,
+    grow_insert_agb_hashmap_random,
+    grow_insert_std_random
+);
+
+macro_rules! bench_insert_erase {
+    ($name:ident, $maptype:ident, $keydist:expr) => {
+        #[bench]
+        fn $name(b: &mut Bencher) {
+            let mut base = $maptype::default();
+            for i in ($keydist).take(SIZE) {
+                base.insert(i, DropType(i));
+            }
+            let skip = $keydist.skip(SIZE);
+            b.iter(|| {
+                let mut m = base.clone();
+                let mut add_iter = skip.clone();
+                let mut remove_iter = $keydist;
+                // While keeping the size constant,
+                // replace the first keydist with the second.
+                for (add, remove) in (&mut add_iter).zip(&mut remove_iter).take(SIZE) {
+                    m.insert(add, DropType(add));
+                    black_box(m.remove(&remove));
+                }
+                black_box(m);
+            });
+            eprintln!("{}", SIDE_EFFECT.load(atomic::Ordering::SeqCst));
+        }
+    };
+}
+
+bench_suite!(
+    bench_insert_erase,
+    insert_erase_agb_hashmap_serial,
+    insert_erase_std_serial,
+    insert_erase_agb_hashmap_highbits,
+    insert_erase_std_highbits,
+    insert_erase_agb_hashmap_random,
+    insert_erase_std_random
+);
+
+macro_rules! bench_lookup {
+    ($name:ident, $maptype:ident, $keydist:expr) => {
+        #[bench]
+        fn $name(b: &mut Bencher) {
+            let mut m = $maptype::default();
+            for i in $keydist.take(SIZE) {
+                m.insert(i, DropType(i));
+            }
+
+            b.iter(|| {
+                for i in $keydist.take(SIZE) {
+                    black_box(m.get(&i));
+                }
+            });
+            eprintln!("{}", SIDE_EFFECT.load(atomic::Ordering::SeqCst));
+        }
+    };
+}
+
+bench_suite!(
+    bench_lookup,
+    lookup_agb_hashmap_serial,
+    lookup_std_serial,
+    lookup_agb_hashmap_highbits,
+    lookup_std_highbits,
+    lookup_agb_hashmap_random,
+    lookup_std_random
+);
+
+macro_rules! bench_lookup_fail {
+    ($name:ident, $maptype:ident, $keydist:expr) => {
+        #[bench]
+        fn $name(b: &mut Bencher) {
+            let mut m = $maptype::default();
+            let mut iter = $keydist;
+            for i in (&mut iter).take(SIZE) {
+                m.insert(i, DropType(i));
+            }
+
+            b.iter(|| {
+                for i in (&mut iter).take(SIZE) {
+                    black_box(m.get(&i));
+                }
+            })
+        }
+    };
+}
+
+bench_suite!(
+    bench_lookup_fail,
+    lookup_fail_agb_hashmap_serial,
+    lookup_fail_std_serial,
+    lookup_fail_agb_hashmap_highbits,
+    lookup_fail_std_highbits,
+    lookup_fail_agb_hashmap_random,
+    lookup_fail_std_random
+);
+
+macro_rules! bench_iter {
+    ($name:ident, $maptype:ident, $keydist:expr) => {
+        #[bench]
+        fn $name(b: &mut Bencher) {
+            let mut m = $maptype::default();
+            for i in ($keydist).take(SIZE) {
+                m.insert(i, DropType(i));
+            }
+
+            b.iter(|| {
+                for i in &m {
+                    black_box(i);
+                }
+            })
+        }
+    };
+}
+
+bench_suite!(
+    bench_iter,
+    iter_agb_hashmap_serial,
+    iter_std_serial,
+    iter_agb_hashmap_highbits,
+    iter_std_highbits,
+    iter_agb_hashmap_random,
+    iter_std_random
+);
+
+macro_rules! clone_bench {
+    ($maptype:ident) => {
+        use super::DropType;
+        use test::{black_box, Bencher};
+
+        #[bench]
+        fn clone_small(b: &mut Bencher) {
+            let mut m = $maptype::new();
+            for i in 0..10 {
+                m.insert(i, DropType(i));
+            }
+
+            b.iter(|| {
+                black_box(m.clone());
+            })
+        }
+
+        #[bench]
+        fn clone_from_small(b: &mut Bencher) {
+            let mut m = $maptype::new();
+            let mut m2 = $maptype::new();
+            for i in 0..10 {
+                m.insert(i, DropType(i));
+            }
+
+            b.iter(|| {
+                m2.clone_from(&m);
+                black_box(&mut m2);
+            })
+        }
+
+        #[bench]
+        fn clone_large(b: &mut Bencher) {
+            let mut m = $maptype::new();
+            for i in 0..1000 {
+                m.insert(i, DropType(i));
+            }
+
+            b.iter(|| {
+                black_box(m.clone());
+            })
+        }
+
+        #[bench]
+        fn clone_from_large(b: &mut Bencher) {
+            let mut m = $maptype::new();
+            let mut m2 = $maptype::new();
+            for i in 0..1000 {
+                m.insert(i, DropType(i));
+            }
+
+            b.iter(|| {
+                m2.clone_from(&m);
+                black_box(&mut m2);
+            })
+        }
+    };
+}
+
+mod agb_hashmap_clone_benches {
+    use agb_hashmap::HashMap;
+    clone_bench!(HashMap);
+}
+
+mod std_hashmap_clone_benches {
+    use std::collections::hash_map::HashMap;
+    clone_bench!(HashMap);
+}