chore: update too fast benches

Some benchmarks are very small and fast and this causes them to
be unstable. We can still keep an eye on the performance with
longer benches. Also increased number of runs and threshold.
This should be fine as all tests still run in nanoseconds.

Signed-off-by: Egor Lazarchuk <[email protected]>

Author: ShadowCurse

src/vmm/benches/block_request.rs

@@ -14,7 +14,7 @@ use vmm::devices::virtio::test_utils::VirtQueue;
 use vmm::test_utils::single_region_mem;
 
 pub fn block_request_benchmark(c: &mut Criterion) {
-    let mem = single_region_mem(2 * 65562);
+    let mem = single_region_mem(65562);
     let virt_queue = VirtQueue::new(GuestAddress(0), &mem, 16);
 
     // We don't really care about what request is. We just
@@ -36,7 +36,7 @@ pub fn block_request_benchmark(c: &mut Criterion) {
 
 criterion_group! {
     name = block_request_benches;
-    config = Criterion::default().sample_size(200).noise_threshold(0.05);
+    config = Criterion::default().sample_size(1000).noise_threshold(0.05);
     targets = block_request_benchmark
 }
 

src/vmm/benches/queue.rs

@@ -59,42 +59,6 @@ pub fn queue_benchmark(c: &mut Criterion) {
     let rxq = VirtQueue::new(GuestAddress(0), &mem, 256);
     let mut queue = rxq.create_queue();
 
-    set_dtable_one_chain(&rxq, 1);
-    queue.next_avail = Wrapping(0);
-    let desc = queue.pop().unwrap();
-    c.bench_function("next_descriptor_1", |b| {
-        b.iter(|| {
-            let mut head = Some(desc);
-            while let Some(d) = head {
-                head = std::hint::black_box(d.next_descriptor());
-            }
-        })
-    });
-
-    set_dtable_one_chain(&rxq, 2);
-    queue.next_avail = Wrapping(0);
-    let desc = queue.pop().unwrap();
-    c.bench_function("next_descriptor_2", |b| {
-        b.iter(|| {
-            let mut head = Some(desc);
-            while let Some(d) = head {
-                head = std::hint::black_box(d.next_descriptor());
-            }
-        })
-    });
-
-    set_dtable_one_chain(&rxq, 4);
-    queue.next_avail = Wrapping(0);
-    let desc = queue.pop().unwrap();
-    c.bench_function("next_descriptor_4", |b| {
-        b.iter(|| {
-            let mut head = Some(desc);
-            while let Some(d) = head {
-                head = std::hint::black_box(d.next_descriptor());
-            }
-        })
-    });
-
     set_dtable_one_chain(&rxq, 16);
     queue.next_avail = Wrapping(0);
     let desc = queue.pop().unwrap();
@@ -107,28 +71,6 @@ pub fn queue_benchmark(c: &mut Criterion) {
         })
     });
 
-    // Queue pop
-
-    set_dtable_many_chains(&rxq, 1);
-    c.bench_function("queue_pop_1", |b| {
-        b.iter(|| {
-            queue.next_avail = Wrapping(0);
-            while let Some(desc) = queue.pop() {
-                std::hint::black_box(desc);
-            }
-        })
-    });
-
-    set_dtable_many_chains(&rxq, 4);
-    c.bench_function("queue_pop_4", |b| {
-        b.iter(|| {
-            queue.next_avail = Wrapping(0);
-            while let Some(desc) = queue.pop() {
-                std::hint::black_box(desc);
-            }
-        })
-    });
-
     set_dtable_many_chains(&rxq, 16);
     c.bench_function("queue_pop_16", |b| {
         b.iter(|| {
@@ -139,18 +81,6 @@ pub fn queue_benchmark(c: &mut Criterion) {
         })
     });
 
-    c.bench_function("queue_add_used_1", |b| {
-        b.iter(|| {
-            queue.num_added = Wrapping(0);
-            queue.next_used = Wrapping(0);
-            for i in 0_u16..1_u16 {
-                let index = std::hint::black_box(i);
-                let len = std::hint::black_box(i + 1);
-                _ = queue.add_used(index as u16, len as u32);
-            }
-        })
-    });
-
     c.bench_function("queue_add_used_16", |b| {
         b.iter(|| {
             queue.num_added = Wrapping(0);
@@ -178,7 +108,7 @@ pub fn queue_benchmark(c: &mut Criterion) {
 
 criterion_group! {
     name = queue_benches;
-    config = Criterion::default().sample_size(200).noise_threshold(0.05);
+    config = Criterion::default().sample_size(1000).noise_threshold(0.15);
     targets = queue_benchmark
 }