diff --git a/library/test/src/bench.rs b/library/test/src/bench.rs
index 23925e6ea72ec..9a5dc351f6d07 100644
--- a/library/test/src/bench.rs
+++ b/library/test/src/bench.rs
@@ -68,12 +68,12 @@ pub fn fmt_bench_samples(bs: &BenchSamples) -> String {
     use std::fmt::Write;
     let mut output = String::new();
 
-    let median = bs.ns_iter_summ.median as usize;
-    let deviation = (bs.ns_iter_summ.max - bs.ns_iter_summ.min) as usize;
+    let median = bs.ns_iter_summ.median;
+    let deviation = bs.ns_iter_summ.max - bs.ns_iter_summ.min;
 
     write!(
         output,
-        "{:>11} ns/iter (+/- {})",
+        "{:>14} ns/iter (+/- {})",
         fmt_thousands_sep(median, ','),
         fmt_thousands_sep(deviation, ',')
     )
@@ -85,24 +85,27 @@ pub fn fmt_bench_samples(bs: &BenchSamples) -> String {
 }
 
 // Format a number with thousands separators
-fn fmt_thousands_sep(mut n: usize, sep: char) -> String {
+fn fmt_thousands_sep(mut n: f64, sep: char) -> String {
     use std::fmt::Write;
     let mut output = String::new();
     let mut trailing = false;
     for &pow in &[9, 6, 3, 0] {
         let base = 10_usize.pow(pow);
-        if pow == 0 || trailing || n / base != 0 {
-            if !trailing {
-                write!(output, "{}", n / base).unwrap();
-            } else {
-                write!(output, "{:03}", n / base).unwrap();
+        if pow == 0 || trailing || n / base as f64 >= 1.0 {
+            match (pow, trailing) {
+                // modern CPUs can execute multiple instructions per nanosecond
+                // e.g. benching an ADD takes about 0.25ns.
+                (0, true) => write!(output, "{:06.2}", n / base as f64).unwrap(),
+                (0, false) => write!(output, "{:.2}", n / base as f64).unwrap(),
+                (_, true) => write!(output, "{:03}", n as usize / base).unwrap(),
+                _ => write!(output,  "{}", n as usize / base).unwrap()
             }
             if pow != 0 {
                 output.push(sep);
             }
             trailing = true;
         }
-        n %= base;
+        n %= base as f64;
     }
 
     output
diff --git a/library/test/src/formatters/json.rs b/library/test/src/formatters/json.rs
index 47c4e7757e40c..6245aae17c4d7 100644
--- a/library/test/src/formatters/json.rs
+++ b/library/test/src/formatters/json.rs
@@ -167,8 +167,8 @@ impl<T: Write> OutputFormatter for JsonFormatter<T> {
             ),
 
             TestResult::TrBench(ref bs) => {
-                let median = bs.ns_iter_summ.median as usize;
-                let deviation = (bs.ns_iter_summ.max - bs.ns_iter_summ.min) as usize;
+                let median = bs.ns_iter_summ.median;
+                let deviation = bs.ns_iter_summ.max - bs.ns_iter_summ.min;
 
                 let mbps = if bs.mb_s == 0 {
                     String::new()
diff --git a/src/bootstrap/src/utils/render_tests.rs b/src/bootstrap/src/utils/render_tests.rs
index 462b76d03bd25..5c9918bce32e1 100644
--- a/src/bootstrap/src/utils/render_tests.rs
+++ b/src/bootstrap/src/utils/render_tests.rs
@@ -215,8 +215,8 @@ impl<'a> Renderer<'a> {
             for bench in &self.benches {
                 rows.push((
                     &bench.name,
-                    format!("{:.2?}/iter", Duration::from_nanos(bench.median)),
-                    format!("+/- {:.2?}", Duration::from_nanos(bench.deviation)),
+                    format!("{:.2?}/iter", bench.median),
+                    format!("+/- {:.2?}", bench.deviation),
                 ));
             }
 
@@ -394,8 +394,8 @@ enum TestMessage {
 #[derive(serde_derive::Deserialize)]
 struct BenchOutcome {
     name: String,
-    median: u64,
-    deviation: u64,
+    median: f64,
+    deviation: f64,
 }
 
 #[derive(serde_derive::Deserialize)]
diff --git a/tests/run-make/libtest-padding/Makefile b/tests/run-make/libtest-padding/Makefile
index 42bc1192925d8..c8e2fc01f677d 100644
--- a/tests/run-make/libtest-padding/Makefile
+++ b/tests/run-make/libtest-padding/Makefile
@@ -2,7 +2,7 @@
 # needs-unwind because #[bench] and -Cpanic=abort requires -Zpanic-abort-tests
 include ../tools.mk
 
-NORMALIZE=sed 's%[0-9,]\{1,\} ns/iter (+/- [0-9,]\{1,\})%?? ns/iter (+/- ??)%' | sed 's%finished in [0-9\.]\{1,\}%finished in ??%'
+NORMALIZE=sed 's%[0-9,\.]\{1,\} ns/iter (+/- [0-9,\.]\{1,\})%?? ns/iter (+/- ??)%' | sed 's%finished in [0-9\.]\{1,\}%finished in ??%'
 
 all:
 	$(RUSTC) --test tests.rs