Move making the vector out of benchmark iter

The difference is within normal noise levels but it's a bit neater.

Bug: 293435349
Test: run benchmark
Change-Id: If46ceaa00a0c57942553e4710a2e8fbc366edefb

2 files changed, 22 insertions, 14 deletions

diff --git a/libatrace_rust/benchmark/README.md b/libatrace_rust/benchmark/README.md
index b80d1627..e8532952 100644
--- a/libatrace_rust/benchmark/README.md
+++ b/libatrace_rust/benchmark/README.md
@@ -48,7 +48,7 @@ device may be different but we expect similar relative performance between Rust
 *If you notice that measurements with tracing off and tracing on have similar times, it might mean
 that enabling ATrace events failed and you need to debug the benchmark.*
 
-### ATrace wrapper benchmark results
+### ATrace wrapper
 
 Rust results from `libatrace_rust_benchmark 2>&1 | grep time`:
 
@@ -75,7 +75,7 @@ BM_TracingOnAtraceBegin/1000        1151 ns         1142 ns       615781
 BM_TracingOnAtraceEnd               1076 ns         1069 ns       653646
 ```
 
-### ATrace tracing subscriber benchmark results
+### ATrace tracing subscriber
 
 The tracing subscriber time consists of the underlying `libatrace_rust` call plus the time spent in
 the subscriber itself.
@@ -83,12 +83,12 @@ the subscriber itself.
 Results from `libatrace_tracing_subscriber_benchmark 2>&1 | grep time`:
 
 ```text
-tracing_off_event       time:   [312.28 ns 314.32 ns 316.71 ns]
-tracing_off_event_args  time:   [2.1963 µs 2.2101 µs 2.2257 µs]
-tracing_off_span        time:   [686.20 ns 707.75 ns 727.21 ns]
-tracing_off_span_args   time:   [2.8813 µs 2.8928 µs 2.9044 µs]
-tracing_on_event        time:   [1.6981 µs 1.7117 µs 1.7264 µs]
-tracing_on_event_args   time:   [3.6242 µs 3.6466 µs 3.6718 µs]
-tracing_on_span         time:   [3.1288 µs 3.1446 µs 3.1612 µs]
-tracing_on_span_args    time:   [5.3117 µs 5.3344 µs 5.3598 µs]
+tracing_off_event       time:   [298.67 ns 299.99 ns 301.52 ns]
+tracing_off_event_args  time:   [2.1225 µs 2.1429 µs 2.1647 µs]
+tracing_off_span        time:   [610.88 ns 619.88 ns 628.70 ns]
+tracing_off_span_args   time:   [2.6585 µs 2.6698 µs 2.6845 µs]
+tracing_on_event        time:   [1.6249 µs 1.6495 µs 1.6887 µs]
+tracing_on_event_args   time:   [3.5608 µs 3.5831 µs 3.6064 µs]
+tracing_on_span         time:   [3.1778 µs 3.1982 µs 3.2211 µs]
+tracing_on_span_args    time:   [5.4340 µs 5.4717 µs 5.5143 µs]
 ```
diff --git a/libatrace_rust/benchmark/src/tracing_subscriber_benchmark.rs b/libatrace_rust/benchmark/src/tracing_subscriber_benchmark.rs
index 07899496..17e9e44a 100644
--- a/libatrace_rust/benchmark/src/tracing_subscriber_benchmark.rs
+++ b/libatrace_rust/benchmark/src/tracing_subscriber_benchmark.rs
@@ -19,6 +19,10 @@ use atrace_tracing_subscriber::AtraceSubscriber;
 use criterion::Criterion;
 use tracing_subscriber::prelude::__tracing_subscriber_SubscriberExt;
 
+fn make_example_vec() -> Vec<i32> {
+    Vec::from([1, 2, 3, 4])
+}
+
 fn bench_with_subscriber<F>(c: &mut Criterion, name: &str, mut f: F)
 where
     F: FnMut(),
@@ -36,10 +40,11 @@ fn bench_tracing_off_event(c: &mut Criterion) {
 
 fn bench_tracing_off_event_args(c: &mut Criterion) {
     turn_tracing_off();
+    let v = make_example_vec();
     bench_with_subscriber(c, "tracing_off_event_args", || {
         tracing::info!(debug_arg1 = 123,
             debug_arg2 = "argument",
-            debug_arg3 = ?Vec::from([1, 2, 3, 4]),
+            debug_arg3 = ?v,
             debug_arg4 = "last",
             "bench info event")
     });
@@ -54,10 +59,11 @@ fn bench_tracing_off_span(c: &mut Criterion) {
 
 fn bench_tracing_off_span_args(c: &mut Criterion) {
     turn_tracing_off();
+    let v = make_example_vec();
     bench_with_subscriber(c, "tracing_off_span_args", || {
         let _entered = tracing::info_span!("bench info span", debug_arg1 = 123,
             debug_arg2 = "argument",
-            debug_arg3 = ?Vec::from([1, 2, 3, 4]),
+            debug_arg3 = ?v,
             debug_arg4 = "last")
         .entered();
     });
@@ -71,10 +77,11 @@ fn bench_tracing_on_event(c: &mut Criterion) {
 
 fn bench_tracing_on_event_args(c: &mut Criterion) {
     turn_tracing_on();
+    let v = make_example_vec();
     bench_with_subscriber(c, "tracing_on_event_args", || {
         tracing::info!(debug_arg1 = 123,
             debug_arg2 = "argument",
-            debug_arg3 = ?Vec::from([1, 2, 3, 4]),
+            debug_arg3 = ?v,
             debug_arg4 = "last",
             "bench info event")
     });
@@ -91,10 +98,11 @@ fn bench_tracing_on_span(c: &mut Criterion) {
 
 fn bench_tracing_on_span_args(c: &mut Criterion) {
     turn_tracing_on();
+    let v = make_example_vec();
     bench_with_subscriber(c, "tracing_on_span_args", || {
         let _entered = tracing::info_span!("bench info span", debug_arg1 = 123,
             debug_arg2 = "argument",
-            debug_arg3 = ?Vec::from([1, 2, 3, 4]),
+            debug_arg3 = ?v,
             debug_arg4 = "last")
         .entered();
     });