add benchmark comparing unsafecell vs refcell

actix-service/Cargo.toml

@@ -21,3 +21,8 @@ pin-project = "0.4.6"
 
 [dev-dependencies]
 actix-rt = "1.0.0"
+criterion = "0.3"
+
+[[bench]]
+name = "unsafecell_vs_refcell"
+harness = false

actix-service/benches/unsafecell_vs_refcell.rs

@@ -0,0 +1,115 @@
+use criterion::{criterion_main, Criterion};
+use futures_util::future::join_all;
+use std::cell::{RefCell, UnsafeCell};
+use std::task::{Context, Poll};
+use std::rc::Rc;
+use actix_service::{Service};
+use futures_util::future::{ok, Ready};
+
+struct SrvUC(Rc<UnsafeCell<usize>>);
+
+impl Default for SrvUC {
+	fn default() -> Self {
+		Self(Rc::new(UnsafeCell::new(0)))
+	}
+}
+
+impl Clone for SrvUC {
+	fn clone(&self) -> Self {
+		Self(self.0.clone())
+	}
+}
+
+impl Service for SrvUC {
+	type Request = ();
+	type Response = usize;
+	type Error = ();
+	type Future = Ready<Result<Self::Response, ()>>;
+
+	fn poll_ready(&mut self, _: &mut Context<'_>) -> Poll<Result<(), Self::Error>> {
+		Poll::Ready(Ok(()))
+	}
+
+	fn call(&mut self, _: ()) -> Self::Future {
+		unsafe { *(*self.0).get() = *(*self.0).get() + 1 };
+		ok(unsafe { *self.0.get() })
+	}
+}
+
+struct SrvRC(Rc<RefCell<usize>>);
+
+impl Default for SrvRC {
+	fn default() -> Self {
+		Self(Rc::new(RefCell::new(0)))
+	}
+}
+
+impl Clone for SrvRC {
+	fn clone(&self) -> Self {
+		Self(self.0.clone())
+	}
+}
+
+impl Service for SrvRC {
+	type Request = ();
+	type Response = usize;
+	type Error = ();
+	type Future = Ready<Result<Self::Response, ()>>;
+
+	fn poll_ready(&mut self, _: &mut Context<'_>) -> Poll<Result<(), Self::Error>> {
+		Poll::Ready(Ok(()))
+	}
+
+	fn call(&mut self, req: ()) -> Self::Future {
+		let prev = *self.0.borrow();
+		*(*self.0).borrow_mut() = prev + 1;
+		ok(*self.0.borrow())
+	}
+}
+
+
+/// Criterion Benchmark for async Service
+/// Should be used from within criterion group:
+/// ```rust,ignore
+/// let mut criterion: ::criterion::Criterion<_> =
+///     ::criterion::Criterion::default().configure_from_args();
+/// bench_async_service(&mut criterion, ok_service(), "async_service_direct");
+/// ```
+///
+/// Usable for benching Service wrappers:
+/// Using minimum service code implementation we first measure
+/// time to run minimum service, then measure time with wrapper.
+///
+/// Sample output
+/// async_service_direct    time:   [1.0908 us 1.1656 us 1.2613 us]
+pub fn bench_async_service<S>(c: &mut Criterion, srv: S, name: &str)
+where
+    S: Service<Request = (), Response = usize, Error = ()> + Clone + 'static,
+{
+    let mut rt = actix_rt::System::new("test");
+
+    // start benchmark loops
+    c.bench_function(name, move |b| {
+        b.iter_custom(|iters| {
+            let mut srvs: Vec<_> = (1..iters).map(|_| srv.clone()).collect();
+            // exclude request generation, it appears it takes significant time vs call (3us vs 1us)
+            let start = std::time::Instant::now();
+            // benchmark body
+            rt.block_on(async move {
+				join_all(srvs.iter_mut().map(|srv| srv.call(()))).await
+			});
+            let elapsed = start.elapsed();
+            // check that at least first request succeeded
+            elapsed
+        })
+    });
+}
+
+
+pub fn service_benches() {
+    let mut criterion: ::criterion::Criterion<_> =
+        ::criterion::Criterion::default().configure_from_args();
+    bench_async_service(&mut criterion, SrvUC::default(), "Service with UnsafeCell");
+    bench_async_service(&mut criterion, SrvRC::default(), "Service with RefCell");
+}
+criterion_main!(service_benches);