diff options
Diffstat (limited to 'core')
| -rw-r--r-- | core/isolate.rs | 32 |
1 files changed, 21 insertions, 11 deletions
diff --git a/core/isolate.rs b/core/isolate.rs index ac5c8402a..ede07b1c5 100644 --- a/core/isolate.rs +++ b/core/isolate.rs @@ -158,6 +158,7 @@ pub struct Isolate { have_unpolled_ops: bool, startup_script: Option<OwnedScript>, op_registry: OpRegistry, + eager_poll_count: u32, } unsafe impl Send for Isolate {} @@ -223,6 +224,7 @@ impl Isolate { pending_dyn_imports: FuturesUnordered::new(), startup_script, op_registry: OpRegistry::new(), + eager_poll_count: 0, } } @@ -315,19 +317,26 @@ impl Isolate { PinnedBuf::new(zero_copy_buf), ); - let op = match op { - Op::Async(mut fut) => { - // Tries to greedily poll async ops once. Often they are immediately ready, in - // which case they can be turned into a sync op before we return to V8. This - // can save a boundary crossing. - #[allow(clippy::match_wild_err_arm)] - match fut.poll() { - Err(_) => panic!("unexpected op error"), - Ok(Ready(buf)) => Op::Sync(buf), - Ok(NotReady) => Op::Async(fut), + // To avoid latency problems we eagerly poll 50 futures and then + // allow to poll ops from `pending_ops` + let op = if isolate.eager_poll_count != 50 { + isolate.eager_poll_count += 1; + match op { + Op::Async(mut fut) => { + // Tries to eagerly poll async ops once. Often they are immediately ready, in + // which case they can be turned into a sync op before we return to V8. This + // can save a boundary crossing. + #[allow(clippy::match_wild_err_arm)] + match fut.poll() { + Err(_) => panic!("unexpected op error"), + Ok(Ready(buf)) => Op::Sync(buf), + Ok(NotReady) => Op::Async(fut), + } } + Op::Sync(buf) => Op::Sync(buf), } - Op::Sync(buf) => Op::Sync(buf), + } else { + op }; debug_assert_eq!(isolate.shared.size(), 0); @@ -647,6 +656,7 @@ impl Future for Isolate { // Now handle actual ops. self.have_unpolled_ops = false; + self.eager_poll_count = 0; #[allow(clippy::match_wild_err_arm)] match self.pending_ops.poll() { Err(_) => panic!("unexpected op error"), |