benches: add bench_err

Cargo.toml

@@ -77,6 +77,10 @@ nightly = []
 name = "bench_call"
 harness = false
 
+[[bench]]
+name = "bench_err"
+harness = false
+
 [[bench]]
 name = "bench_dict"
 harness = false

benches/bench_err.rs

@@ -0,0 +1,24 @@
+use criterion::{criterion_group, criterion_main, Bencher, Criterion};
+
+use pyo3::{exceptions::PyValueError, prelude::*};
+
+fn err_new_restore_and_fetch(b: &mut Bencher) {
+    Python::with_gil(|py| {
+        b.iter(|| {
+            PyValueError::new_err("some exception message").restore(py);
+            PyErr::fetch(py)
+        })
+    })
+}
+
+fn err_new_without_gil(b: &mut Bencher) {
+    b.iter(|| PyValueError::new_err("some exception message"))
+}
+
+fn criterion_benchmark(c: &mut Criterion) {
+    c.bench_function("err_new_restore_and_fetch", err_new_restore_and_fetch);
+    c.bench_function("err_new_without_gil", err_new_without_gil);
+}
+
+criterion_group!(benches, criterion_benchmark);
+criterion_main!(benches);