From 8083ae660244856d162b6db455aa5250afa02d8e Mon Sep 17 00:00:00 2001
From: Max Brunsfeld <maxbrunsfeld@gmail.com>
Date: Fri, 2 Aug 2019 12:01:35 -0700
Subject: [PATCH] benchmark: Parse each sample a configurable number of times

Refs #343
---
 cli/benches/benchmark.rs | 16 ++++++++++++----
 script/benchmark         |  9 +++++++--
 2 files changed, 19 insertions(+), 6 deletions(-)

diff --git a/cli/benches/benchmark.rs b/cli/benches/benchmark.rs
index ef67bd21..667b566b 100644
--- a/cli/benches/benchmark.rs
+++ b/cli/benches/benchmark.rs
@@ -14,6 +14,10 @@ lazy_static! {
         env::var("TREE_SITTER_BENCHMARK_LANGUAGE_FILTER").ok();
     static ref EXAMPLE_FILTER: Option<String> =
         env::var("TREE_SITTER_BENCHMARK_EXAMPLE_FILTER").ok();
+    static ref REPETITION_COUNT: usize = env::var("TREE_SITTER_BENCHMARK_REPETITION_COUNT")
+        .map(|s| usize::from_str_radix(&s, 10).unwrap())
+        .unwrap_or(5);
+
     static ref TEST_LOADER: Loader = Loader::new(SCRATCH_DIR.clone());
     static ref EXAMPLE_PATHS_BY_LANGUAGE_DIR: BTreeMap<PathBuf, Vec<PathBuf>> = {
         fn process_dir(result: &mut BTreeMap<PathBuf, Vec<PathBuf>>, dir: &Path) {
@@ -73,6 +77,8 @@ fn main() {
             }
         }
 
+        eprintln!("Benchmarking with {} repetitions", *REPETITION_COUNT);
+
         eprintln!("\nLanguage: {}", language_name);
         parser.set_language(get_language(language_path)).unwrap();
 
@@ -157,10 +163,12 @@ fn parse(parser: &mut Parser, example_path: &Path, max_path_length: usize) -> us
         .map_err(Error::wrap(|| format!("Failed to read {:?}", example_path)))
         .unwrap();
     let time = Instant::now();
-    let _tree = parser
-        .parse(&source_code, None)
-        .expect("Incompatible language version");
-    let duration = time.elapsed();
+    for _ in 0..*REPETITION_COUNT {
+        parser
+            .parse(&source_code, None)
+            .expect("Incompatible language version");
+    }
+    let duration = time.elapsed() / (*REPETITION_COUNT as u32);
     let duration_ms =
         duration.as_secs() as f64 * 1000.0 + duration.subsec_nanos() as f64 / 1000000.0;
     let speed = (source_code.len() as f64 / duration_ms) as usize;
diff --git a/script/benchmark b/script/benchmark
index 9b4ec3f0..5be3465b 100755
--- a/script/benchmark
+++ b/script/benchmark
@@ -6,7 +6,7 @@ function usage {
   cat <<-EOF
 USAGE
 
-  $0  [-h] [-l language-name] [-e example-file-name]
+  $0  [-h] [-l language-name] [-e example-file-name] [-r repetition-count]
 
 OPTIONS
 
@@ -16,10 +16,12 @@ OPTIONS
 
   -e  run only the benchmarks that parse the example file with the given name
 
+  -r  parse each sample the given number of times (default 5)
+
 EOF
 }
 
-while getopts "hl:e:" option; do
+while getopts "hl:e:r:" option; do
   case ${option} in
     h)
       usage
@@ -31,6 +33,9 @@ while getopts "hl:e:" option; do
     l)
       export TREE_SITTER_BENCHMARK_LANGUAGE_FILTER=${OPTARG}
       ;;
+    r)
+      export TREE_SITTER_BENCHMARK_REPETITION_COUNT=${OPTARG}
+      ;;
   esac
 done