Add Throughput::BytesDecimal. Fixes #581.

Author: bheisler

CHANGELOG.md

@@ -32,9 +32,11 @@ and this project adheres to [Semantic Versioning](http://semver.org/spec/v2.0.0.
 - A `--discard-baseline` flag for discarding rather than saving benchmark results.
 - Formal support for benchmarking code compiled to web-assembly.
 - A `--quiet` flag for printing just a single line per benchmark.
+- A `Throughput::BytesDecimal` option for measuring throughput in bytes but printing them using
+  decimal units like kilobytes instead of binary units like kibibytes.
 
 ### Fixed
-- When using `bench_with_input`, the input parameter will now be passed through `black_box` before 
+- When using `bench_with_input`, the input parameter will now be passed through `black_box` before
   passing it to the benchmark.
 
 ## [0.3.6] - 2022-07-06
@@ -502,12 +504,7 @@ and this project adheres to [Semantic Versioning](http://semver.org/spec/v2.0.0.
 
 - Initial release on Crates.io.
 
-<<<<<<< HEAD
-[unreleased]: https://github.com/bheisler/criterion.rs/compare/0.3.4...HEAD
-=======
-
 [Unreleased]: https://github.com/bheisler/criterion.rs/compare/0.3.6...HEAD
->>>>>>> master
 [0.1.1]: https://github.com/bheisler/criterion.rs/compare/0.1.0...0.1.1
 [0.1.2]: https://github.com/bheisler/criterion.rs/compare/0.1.1...0.1.2
 [0.2.0]: https://github.com/bheisler/criterion.rs/compare/0.1.2...0.2.0
@@ -528,4 +525,4 @@ and this project adheres to [Semantic Versioning](http://semver.org/spec/v2.0.0.
 [0.3.3]: https://github.com/bheisler/criterion.rs/compare/0.3.2...0.3.3
 [0.3.4]: https://github.com/bheisler/criterion.rs/compare/0.3.3...0.3.4
 [0.3.5]: https://github.com/bheisler/criterion.rs/compare/0.3.4...0.3.5
-[0.3.5]: https://github.com/bheisler/criterion.rs/compare/0.3.5...0.3.6
+[0.3.5]: https://github.com/bheisler/criterion.rs/compare/0.3.5...0.3.6

benches/benchmarks/custom_measurement.rs

@@ -14,7 +14,7 @@ impl ValueFormatter for HalfSecFormatter {
 
     fn format_throughput(&self, throughput: &Throughput, value: f64) -> String {
         match *throughput {
-            Throughput::Bytes(bytes) => {
+            Throughput::Bytes(bytes) | Throughput::BytesDecimal(bytes) => {
                 format!("{} b/s/2", (bytes as f64) / (value * 2f64 * 10f64.powi(-9)))
             }
             Throughput::Elements(elems) => format!(
@@ -39,7 +39,7 @@ impl ValueFormatter for HalfSecFormatter {
         values: &mut [f64],
     ) -> &'static str {
         match *throughput {
-            Throughput::Bytes(bytes) => {
+            Throughput::Bytes(bytes) | Throughput::BytesDecimal(bytes) => {
                 for val in values {
                     *val = (bytes as f64) / (*val * 2f64 * 10f64.powi(-9))
                 }

benches/benchmarks/with_inputs.rs

@@ -13,6 +13,15 @@ fn from_elem(c: &mut Criterion) {
         });
     }
     group.finish();
+
+    let mut group = c.benchmark_group("from_elem_decimal");
+    for size in [KB, 2 * KB].iter() {
+        group.throughput(Throughput::BytesDecimal(*size as u64));
+        group.bench_with_input(BenchmarkId::from_parameter(size), size, |b, &size| {
+            b.iter(|| iter::repeat(0u8).take(size).collect::<Vec<_>>());
+        });
+    }
+    group.finish();
 }
 
 criterion_group!(benches, from_elem);

src/lib.rs

@@ -1207,6 +1207,11 @@ pub enum Throughput {
     /// an input string or `&[u8]`.
     Bytes(u64),
 
+    /// Equivalent to Bytes, but the value will be reported in terms of
+    /// kilobytes (1000 bytes) per second instead of kibibytes (1024 bytes) per
+    /// second, megabytes instead of mibibytes, and gigabytes instead of gibibytes.
+    BytesDecimal(u64),
+
     /// Measure throughput in terms of elements/second. The value should be the number of elements
     /// processed by one iteration of the benchmarked code. Typically, this would be the size of a
     /// collection, but could also be the number of lines of input text or the number of values to

src/measurement.rs

@@ -124,6 +124,31 @@ impl DurationFormatter {
         unit
     }
 
+    fn bytes_per_second_decimal(
+        &self,
+        bytes: f64,
+        typical: f64,
+        values: &mut [f64],
+    ) -> &'static str {
+        let bytes_per_second = bytes * (1e9 / typical);
+        let (denominator, unit) = if bytes_per_second < 1000.0 {
+            (1.0, "  B/s")
+        } else if bytes_per_second < 1000.0 * 1000.0 {
+            (1000.0, "KB/s")
+        } else if bytes_per_second < 1000.0 * 1000.0 * 1000.0 {
+            (1000.0 * 1000.0, "MB/s")
+        } else {
+            (1000.0 * 1000.0 * 1000.0, "GB/s")
+        };
+
+        for val in values {
+            let bytes_per_second = bytes * (1e9 / *val);
+            *val = bytes_per_second / denominator;
+        }
+
+        unit
+    }
+
     fn elements_per_second(&self, elems: f64, typical: f64, values: &mut [f64]) -> &'static str {
         let elems_per_second = elems * (1e9 / typical);
         let (denominator, unit) = if elems_per_second < 1000.0 {
@@ -153,6 +178,9 @@ impl ValueFormatter for DurationFormatter {
     ) -> &'static str {
         match *throughput {
             Throughput::Bytes(bytes) => self.bytes_per_second(bytes as f64, typical, values),
+            Throughput::BytesDecimal(bytes) => {
+                self.bytes_per_second_decimal(bytes as f64, typical, values)
+            }
             Throughput::Elements(elems) => self.elements_per_second(elems as f64, typical, values),
         }
     }

src/report.rs

@@ -173,7 +173,9 @@ impl BenchmarkId {
 
     pub fn as_number(&self) -> Option<f64> {
         match self.throughput {
-            Some(Throughput::Bytes(n)) | Some(Throughput::Elements(n)) => Some(n as f64),
+            Some(Throughput::Bytes(n))
+            | Some(Throughput::Elements(n))
+            | Some(Throughput::BytesDecimal(n)) => Some(n as f64),
             None => self
                 .value_str
                 .as_ref()
@@ -184,6 +186,7 @@ impl BenchmarkId {
     pub fn value_type(&self) -> Option<ValueType> {
         match self.throughput {
             Some(Throughput::Bytes(_)) => Some(ValueType::Bytes),
+            Some(Throughput::BytesDecimal(_)) => Some(ValueType::Bytes),
             Some(Throughput::Elements(_)) => Some(ValueType::Elements),
             None => self
                 .value_str