perf: use fast api for op_now (#15643)

6 files changed, 80 insertions, 22 deletions

diff --git a/cli/bench/op_now.js b/cli/bench/op_now.js
new file mode 100644
index 000000000..edce96fed
--- /dev/null
+++ b/cli/bench/op_now.js
@@ -0,0 +1,19 @@
+// Copyright 2018-2022 the Deno authors. All rights reserved. MIT license.
+const queueMicrotask = globalThis.queueMicrotask || process.nextTick;
+let [total, count] = typeof Deno !== "undefined"
+  ? Deno.args
+  : [process.argv[2], process.argv[3]];
+
+total = total ? parseInt(total, 0) : 50;
+count = count ? parseInt(count, 10) : 10000000;
+
+function bench(fun) {
+  const start = Date.now();
+  for (let i = 0; i < count; i++) fun();
+  const elapsed = Date.now() - start;
+  const rate = Math.floor(count / (elapsed / 1000));
+  console.log(`time ${elapsed} ms rate ${rate}`);
+  if (--total) queueMicrotask(() => bench(fun));
+}
+
+bench(() => performance.now());
diff --git a/ext/web/02_timers.js b/ext/web/02_timers.js
index 07b9587ea..f703120e6 100644
--- a/ext/web/02_timers.js
+++ b/ext/web/02_timers.js
@@ -13,6 +13,7 @@
     MapPrototypeGet,
     MapPrototypeHas,
     MapPrototypeSet,
+    Uint32Array,
     // deno-lint-ignore camelcase
     NumberPOSITIVE_INFINITY,
     PromisePrototypeThen,
@@ -25,8 +26,14 @@
   const { reportException } = window.__bootstrap.event;
   const { assert } = window.__bootstrap.infra;
 
+  let hr;
   function opNow() {
-    return ops.op_now();
+    if (!hr) {
+      hr = new Uint32Array(2);
+      ops.op_now_set_buf(hr);
+    }
+    ops.op_now.fast();
+    return (hr[0] * 1000 + hr[1] / 1e6);
   }
 
   // ---------------------------------------------------------------------------
diff --git a/ext/web/benches/timers_ops.rs b/ext/web/benches/timers_ops.rs
index f5d03d6c3..10b434015 100644
--- a/ext/web/benches/timers_ops.rs
+++ b/ext/web/benches/timers_ops.rs
@@ -1,8 +1,8 @@
 use deno_core::Extension;
 
+use deno_bench_util::bench_js_async;
 use deno_bench_util::bench_or_profile;
 use deno_bench_util::bencher::{benchmark_group, Bencher};
-use deno_bench_util::{bench_js_async, bench_js_sync};
 use deno_web::BlobStore;
 
 struct Permissions;
@@ -27,7 +27,7 @@ fn setup() -> Vec<Extension> {
     Extension::builder()
     .js(vec![
       ("setup", r#"
-      const { opNow, setTimeout, handleTimerMacrotask } = globalThis.__bootstrap.timers;
+      const { setTimeout, handleTimerMacrotask } = globalThis.__bootstrap.timers;
       Deno.core.setMacrotaskCallback(handleTimerMacrotask);
       "#),
     ])
@@ -39,13 +39,9 @@ fn setup() -> Vec<Extension> {
   ]
 }
 
-fn bench_op_now(b: &mut Bencher) {
-  bench_js_sync(b, r#"opNow();"#, setup);
-}
-
 fn bench_set_timeout(b: &mut Bencher) {
   bench_js_async(b, r#"setTimeout(() => {}, 0);"#, setup);
 }
 
-benchmark_group!(benches, bench_op_now, bench_set_timeout,);
+benchmark_group!(benches, bench_set_timeout,);
 bench_or_profile!(benches);
diff --git a/ext/web/lib.rs b/ext/web/lib.rs
index a80447614..91c680f5f 100644
--- a/ext/web/lib.rs
+++ b/ext/web/lib.rs
@@ -51,6 +51,7 @@ pub use crate::message_port::JsMessageData;
 pub use crate::message_port::MessagePort;
 
 use crate::timers::op_now;
+use crate::timers::op_now_set_buf;
 use crate::timers::op_sleep;
 use crate::timers::op_timer_handle;
 use crate::timers::StartTime;
@@ -106,6 +107,7 @@ pub fn init<P: TimersPermission + 'static>(
       compression::op_compression_new::decl(),
       compression::op_compression_write::decl(),
       compression::op_compression_finish::decl(),
+      op_now_set_buf::decl(),
       op_now::decl::<P>(),
       op_timer_handle::decl(),
       op_cancel_handle::decl(),
diff --git a/ext/web/timers.rs b/ext/web/timers.rs
index 0f781a579..d9ceef875 100644
--- a/ext/web/timers.rs
+++ b/ext/web/timers.rs
@@ -4,6 +4,7 @@
 
 use deno_core::error::AnyError;
 use deno_core::op;
+use deno_core::ZeroCopyBuf;
 
 use deno_core::CancelFuture;
 use deno_core::CancelHandle;
@@ -23,29 +24,50 @@ pub trait TimersPermission {
 
 pub type StartTime = Instant;
 
+static mut NOW_BUF: *mut u32 = std::ptr::null_mut();
+
+#[op]
+pub fn op_now_set_buf(buf: ZeroCopyBuf) {
+  assert_eq!(buf.len(), 8);
+  // SAFETY: This is safe because this is the only place where we initialize
+  // NOW_BUF.
+  unsafe {
+    NOW_BUF = buf.as_ptr() as *mut u32;
+  }
+}
+
 // Returns a milliseconds and nanoseconds subsec
 // since the start time of the deno runtime.
 // If the High precision flag is not set, the
 // nanoseconds are rounded on 2ms.
-#[op]
-pub fn op_now<TP>(state: &mut OpState) -> f64
+#[op(fast)]
+pub fn op_now<TP>(state: &mut OpState)
 where
   TP: TimersPermission + 'static,
 {
   let start_time = state.borrow::<StartTime>();
   let elapsed = start_time.elapsed();
   let seconds = elapsed.as_secs();
-  let mut subsec_nanos = elapsed.subsec_nanos() as f64;
-  let reduced_time_precision = 2_000_000.0; // 2ms in nanoseconds
+  let mut subsec_nanos = elapsed.subsec_nanos();
 
   // If the permission is not enabled
   // Round the nano result on 2 milliseconds
   // see: https://developer.mozilla.org/en-US/docs/Web/API/DOMHighResTimeStamp#Reduced_time_precision
   if !state.borrow_mut::<TP>().allow_hrtime() {
+    let reduced_time_precision = 2_000_000; // 2ms in nanoseconds
     subsec_nanos -= subsec_nanos % reduced_time_precision;
   }
 
-  (seconds * 1_000) as f64 + (subsec_nanos / 1_000_000.0)
+  // SAFETY: This is safe because we initialize NOW_BUF in op_now_set_buf, its a null pointer
+  // otherwise.
+  // op_now_set_buf guarantees that the buffer is 8 bytes long.
+  unsafe {
+    if !NOW_BUF.is_null() {
+      let buf = std::slice::from_raw_parts_mut(NOW_BUF, 2);
+      buf[0] = seconds as u32;
+      buf[1] = subsec_nanos as u32;
+    }
+  }
 }
 
 pub struct TimerHandle(Rc<CancelHandle>);
diff --git a/ops/lib.rs b/ops/lib.rs
index 2028fc875..500e1f5f9 100644
--- a/ops/lib.rs
+++ b/ops/lib.rs
@@ -365,15 +365,32 @@ fn codegen_fast_impl(
             }
           },
           quote! {
-            #func_name #ty_generics as *const _
+            #func_name::<#type_params> as *const _
           },
         )
       };
+
+      let fast_struct = format_ident!("fast_{}", name);
+      let (type_params, ty_generics, struct_generics) =
+        if type_params.is_empty() {
+          (quote! { () }, quote! {}, quote! {})
+        } else {
+          (
+            quote! { #type_params },
+            quote! { #ty_generics },
+            quote! { ::<#type_params> },
+          )
+        };
       return (
         quote! {
+          #[allow(non_camel_case_types)]
+          #[doc(hidden)]
+          struct #fast_struct #ty_generics {
+            _phantom: ::std::marker::PhantomData<#type_params>,
+          }
           #trampoline
-          impl #impl_generics #core::v8::fast_api::FastFunction for #name #ty_generics {
-            fn function(&self) -> *const ::std::ffi::c_void {
+          impl #impl_generics #core::v8::fast_api::FastFunction for #fast_struct #ty_generics #where_clause {
+            fn function(&self) -> *const ::std::ffi::c_void  {
               #raw_block
             }
             fn args(&self) -> &'static [#core::v8::fast_api::Type] {
@@ -384,7 +401,7 @@ fn codegen_fast_impl(
             }
           }
         },
-        quote! { Some(Box::new(#name #ty_generics)) },
+        quote! { Some(Box::new(#fast_struct #struct_generics { _phantom: ::std::marker::PhantomData })) },
       );
     }
   }
@@ -439,11 +456,6 @@ struct FastApiSyn {
 }
 
 fn can_be_fast_api(core: &TokenStream2, f: &syn::ItemFn) -> Option<FastApiSyn> {
-  // TODO(@littledivy): Support generics
-  if !f.sig.generics.params.is_empty() {
-    return None;
-  }
-
   let inputs = &f.sig.inputs;
   let ret = match &f.sig.output {
     syn::ReturnType::Default => quote!(#core::v8::fast_api::CType::Void),