Add benchmark for function-call overhead

fidget/Cargo.toml

@@ -78,5 +78,9 @@ harness = false
 name = "mesh"
 harness = false
 
+[[bench]]
+name = "function_call"
+harness = false
+
 [lib]
 bench = false

fidget/benches/function_call.rs

@@ -0,0 +1,75 @@
+use criterion::{
+    black_box, criterion_group, criterion_main, BenchmarkId, Criterion,
+};
+use fidget::{
+    context::{Context, Node},
+    eval::{BulkEvaluator, EzShape, MathShape, Shape},
+};
+
+pub fn run_bench<S: Shape + MathShape>(
+    c: &mut Criterion,
+    ctx: Context,
+    node: Node,
+    test_name: &'static str,
+    name: &'static str,
+) {
+    let shape_vm = &S::new(&ctx, node).unwrap();
+
+    let mut eval = S::new_float_slice_eval();
+    let tape = shape_vm.ez_float_slice_tape();
+
+    let mut group = c.benchmark_group(test_name);
+    for n in [10, 100, 1000] {
+        let data = (0..n).map(|i| i as f32 / n as f32).collect::<Vec<f32>>();
+        let t = &tape;
+        group.bench_function(BenchmarkId::new(name, n), |b| {
+            b.iter(|| {
+                black_box(eval.eval(t, &data, &data, &data, &[]).unwrap());
+            })
+        });
+    }
+}
+
+pub fn test_single_fn<S: Shape + MathShape>(
+    c: &mut Criterion,
+    name: &'static str,
+) {
+    let mut ctx = Context::new();
+    let x = ctx.x();
+    let f = ctx.sin(x).unwrap();
+
+    run_bench::<S>(c, ctx, f, "single function", name);
+}
+
+pub fn test_many_fn<S: Shape + MathShape>(
+    c: &mut Criterion,
+    name: &'static str,
+) {
+    let mut ctx = Context::new();
+    let x = ctx.x();
+    let f = ctx.sin(x).unwrap();
+    let y = ctx.y();
+    let g = ctx.cos(y).unwrap();
+    let z = ctx.z();
+    let h = ctx.exp(z).unwrap();
+
+    let out = ctx.add(f, g).unwrap();
+    let out = ctx.add(out, h).unwrap();
+
+    run_bench::<S>(c, ctx, out, "many functions", name);
+}
+
+pub fn test_single_fns(c: &mut Criterion) {
+    test_single_fn::<fidget::vm::VmShape>(c, "vm");
+    #[cfg(feature = "jit")]
+    test_single_fn::<fidget::jit::JitShape>(c, "jit");
+}
+
+pub fn test_many_fns(c: &mut Criterion) {
+    test_many_fn::<fidget::vm::VmShape>(c, "vm");
+    #[cfg(feature = "jit")]
+    test_many_fn::<fidget::jit::JitShape>(c, "jit");
+}
+
+criterion_group!(benches, test_single_fns, test_many_fns);
+criterion_main!(benches);