Include dropping behaviour in bench

Author: Markus Westerlind

benches/bench.rs

@@ -10,7 +10,10 @@ use test::{black_box, Bencher};
 
 use hashbrown::hash_map::DefaultHashBuilder;
 use hashbrown::HashMap;
-use std::collections::hash_map::RandomState;
+use std::{
+    collections::hash_map::RandomState,
+    sync::atomic::{self, AtomicUsize},
+};
 
 const SIZE: usize = 1000;
 
@@ -40,6 +43,19 @@ impl Iterator for RandomKeys {
     }
 }
 
+// Just an arbitrary side effect to
+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_ahash_serial:ident, $bench_std_serial:ident,
      $bench_ahash_highbits:ident, $bench_std_highbits:ident,
@@ -69,10 +85,11 @@ macro_rules! bench_insert {
             b.iter(|| {
                 m.clear();
                 for i in ($keydist).take(SIZE) {
-                    m.insert(i, i);
+                    m.insert(i, DropType(i));
                 }
                 black_box(&mut m);
-            })
+            });
+            eprintln!("{}", SIDE_EFFECT.load(atomic::Ordering::SeqCst));
         }
     };
 }
@@ -93,7 +110,7 @@ macro_rules! bench_insert_erase {
         fn $name(b: &mut Bencher) {
             let mut base = $maptype::default();
             for i in ($keydist).take(SIZE) {
-                base.insert(i, i);
+                base.insert(i, DropType(i));
             }
             let skip = $keydist.skip(SIZE);
             b.iter(|| {
@@ -103,11 +120,12 @@ macro_rules! bench_insert_erase {
                 // 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, add);
+                    m.insert(add, DropType(add));
                     black_box(m.remove(&remove));
                 }
                 black_box(m);
-            })
+            });
+            eprintln!("{}", SIDE_EFFECT.load(atomic::Ordering::SeqCst));
         }
     };
 }
@@ -128,14 +146,15 @@ macro_rules! bench_lookup {
         fn $name(b: &mut Bencher) {
             let mut m = $maptype::default();
             for i in $keydist.take(SIZE) {
-                m.insert(i, i);
+                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));
         }
     };
 }
@@ -157,7 +176,7 @@ macro_rules! bench_lookup_fail {
             let mut m = $maptype::default();
             let mut iter = $keydist;
             for i in (&mut iter).take(SIZE) {
-                m.insert(i, i);
+                m.insert(i, DropType(i));
             }
 
             b.iter(|| {
@@ -185,7 +204,7 @@ macro_rules! bench_iter {
         fn $name(b: &mut Bencher) {
             let mut m = $maptype::default();
             for i in ($keydist).take(SIZE) {
-                m.insert(i, i);
+                m.insert(i, DropType(i));
             }
 
             b.iter(|| {
@@ -211,7 +230,7 @@ bench_suite!(
 fn clone_small(b: &mut Bencher) {
     let mut m = HashMap::new();
     for i in 0..10 {
-        m.insert(i, i);
+        m.insert(i, DropType(i));
     }
 
     b.iter(|| {
@@ -224,7 +243,7 @@ fn clone_from_small(b: &mut Bencher) {
     let mut m = HashMap::new();
     let mut m2 = HashMap::new();
     for i in 0..10 {
-        m.insert(i, i);
+        m.insert(i, DropType(i));
     }
 
     b.iter(|| {
@@ -237,7 +256,7 @@ fn clone_from_small(b: &mut Bencher) {
 fn clone_large(b: &mut Bencher) {
     let mut m = HashMap::new();
     for i in 0..1000 {
-        m.insert(i, i);
+        m.insert(i, DropType(i));
     }
 
     b.iter(|| {
@@ -250,7 +269,7 @@ fn clone_from_large(b: &mut Bencher) {
     let mut m = HashMap::new();
     let mut m2 = HashMap::new();
     for i in 0..1000 {
-        m.insert(i, i);
+        m.insert(i, DropType(i));
     }
 
     b.iter(|| {