[turbopack] Drop duration and allocation tracking from CaptureFuture (#85534)

lukesandberg · web-flow · commit 67aa5f3d2817 · 2025-11-04T16:26:36.000-08:00
This data was mostly unused

* allocation tracking was completely dead.  So this saves a bit of memory and some data copies
* duration tracking was only used for task statistics.  This was a relatively new feature and not particularly useful.  I considered wrapping it in a `feature` but dropping is simpler and this data is very redundant with tracing output anyway.
diff --git a/turbopack/crates/turbo-tasks-backend/benches/overhead.rs b/turbopack/crates/turbo-tasks-backend/benches/overhead.rs
@@ -3,7 +3,7 @@ use std::time::{Duration, Instant};
 use criterion::{BenchmarkId, Criterion, black_box};
 use futures::{FutureExt, StreamExt, stream::FuturesUnordered};
 use tokio::spawn;
-use turbo_tasks::{TurboTasks, TurboTasksApi};
+use turbo_tasks::TurboTasks;
 use turbo_tasks_backend::{BackendOptions, TurboTasksBackend, noop_backing_storage};
 
 #[global_allocator]
@@ -79,15 +79,6 @@ pub fn overhead(c: &mut Criterion) {
                 run_turbo::<Uncached>(&rt, b, d, false);
             },
         );
-        // Same as turbo-uncached but reports the time as measured by turbotasks itself
-        // This allows us to understand the cost of the indirection within turbotasks
-        group.bench_with_input(
-            BenchmarkId::new("turbo-uncached-stats", micros),
-            &duration,
-            |b, &d| {
-                run_turbo_stats(&rt, b, d);
-            },
-        );
 
         group.bench_with_input(
             BenchmarkId::new("turbo-cached-same-keys", micros),
@@ -224,29 +215,3 @@ fn run_turbo<Mode: TurboMode>(
         }
     });
 }
-
-fn run_turbo_stats(rt: &tokio::runtime::Runtime, b: &mut criterion::Bencher<'_>, d: Duration) {
-    b.to_async(rt).iter_custom(|iters| {
-        // It is important to create the tt instance here to ensure the cache is not shared across
-        // iterations.
-        let tt = TurboTasks::new(TurboTasksBackend::new(
-            BackendOptions {
-                storage_mode: None,
-                ..Default::default()
-            },
-            noop_backing_storage(),
-        ));
-        let stats = tt.task_statistics().enable().clone();
-
-        async move {
-            tt.run_once(async move {
-                for i in 0..iters {
-                    black_box(busy_turbo(i, black_box(d)).await?);
-                }
-                Ok(stats.get(&BUSY_TURBO_FUNCTION).duration)
-            })
-            .await
-            .unwrap()
-        }
-    });
-}
diff --git a/turbopack/crates/turbo-tasks-backend/src/backend/mod.rs b/turbopack/crates/turbo-tasks-backend/src/backend/mod.rs
@@ -391,14 +391,6 @@ impl<B: BackingStorage> TurboTasksBackendInner<B> {
         self.task_statistics
             .map(|stats| stats.increment_cache_miss(task_type.native_fn));
     }
-
-    fn track_task_duration(&self, task_id: TaskId, duration: std::time::Duration) {
-        self.task_statistics.map(|stats| {
-            if let Some(task_type) = self.task_cache.lookup_reverse(&task_id) {
-                stats.increment_execution_duration(task_type.native_fn, duration);
-            }
-        });
-    }
 }
 
 pub(crate) struct OperationGuard<'a, B: BackingStorage> {
@@ -1751,8 +1743,6 @@ impl<B: BackingStorage> TurboTasksBackendInner<B> {
     fn task_execution_completed(
         &self,
         task_id: TaskId,
-        duration: Duration,
-        _memory_usage: usize,
         result: Result<RawVc, TurboTasksExecutionError>,
         cell_counters: &AutoMap<ValueTypeId, u32, BuildHasherDefault<FxHasher>, 8>,
         stateful: bool,
@@ -1776,8 +1766,6 @@ impl<B: BackingStorage> TurboTasksBackendInner<B> {
         let span = tracing::trace_span!("task execution completed", immutable = Empty).entered();
         let mut ctx = self.execute_context(turbo_tasks);
 
-        self.track_task_duration(task_id, duration);
-
         let Some(TaskExecutionCompletePrepareResult {
             new_children,
             mut removed_data,
@@ -3194,8 +3182,6 @@ impl<B: BackingStorage> Backend for TurboTasksBackend<B> {
     fn task_execution_completed(
         &self,
         task_id: TaskId,
-        _duration: Duration,
-        _memory_usage: usize,
         result: Result<RawVc, TurboTasksExecutionError>,
         cell_counters: &AutoMap<ValueTypeId, u32, BuildHasherDefault<FxHasher>, 8>,
         stateful: bool,
@@ -3204,8 +3190,6 @@ impl<B: BackingStorage> Backend for TurboTasksBackend<B> {
     ) -> bool {
         self.0.task_execution_completed(
             task_id,
-            _duration,
-            _memory_usage,
             result,
             cell_counters,
             stateful,
diff --git a/turbopack/crates/turbo-tasks/src/backend.rs b/turbopack/crates/turbo-tasks/src/backend.rs
@@ -6,7 +6,6 @@ use std::{
     hash::{BuildHasherDefault, Hash},
     pin::Pin,
     sync::Arc,
-    time::Duration,
 };
 
 use anyhow::{Result, anyhow};
@@ -541,8 +540,6 @@ pub trait Backend: Sync + Send {
     fn task_execution_completed(
         &self,
         task: TaskId,
-        duration: Duration,
-        memory_usage: usize,
         result: Result<RawVc, TurboTasksExecutionError>,
         cell_counters: &AutoMap<ValueTypeId, u32, BuildHasherDefault<FxHasher>, 8>,
         stateful: bool,
diff --git a/turbopack/crates/turbo-tasks/src/capture_future.rs b/turbopack/crates/turbo-tasks/src/capture_future.rs
@@ -1,74 +1,31 @@
 use std::{
     borrow::Cow,
-    cell::RefCell,
     fmt::Display,
     future::Future,
     panic,
     pin::Pin,
     task::{Context, Poll},
-    time::{Duration, Instant},
 };
 
 use anyhow::Result;
 use pin_project_lite::pin_project;
 use serde::{Deserialize, Serialize};
-use turbo_tasks_malloc::{AllocationInfo, TurboMalloc};
 
 use crate::{backend::TurboTasksExecutionErrorMessage, panic_hooks::LAST_ERROR_LOCATION};
 
-struct ThreadLocalData {
-    duration: Duration,
-    allocations: usize,
-    deallocations: usize,
-}
-
-thread_local! {
-    static EXTRA: RefCell<Option<*mut ThreadLocalData>> = const { RefCell::new(None) };
-}
-
 pin_project! {
     pub struct CaptureFuture<T, F: Future<Output = T>> {
         #[pin]
         future: F,
-        duration: Duration,
-        allocations: AllocationInfo,
     }
 }
 
 impl<T, F: Future<Output = T>> CaptureFuture<T, F> {
     pub fn new(future: F) -> Self {
-        Self {
-            future,
-            duration: Duration::ZERO,
-            allocations: AllocationInfo::ZERO,
-        }
+        Self { future }
     }
 }
 
-fn try_with_thread_local_data(f: impl FnOnce(&mut ThreadLocalData)) {
-    EXTRA.with_borrow(|cell| {
-        if let Some(data) = cell {
-            // Safety: This data is thread local and only accessed in this thread
-            unsafe {
-                f(&mut **data);
-            }
-        }
-    });
-}
-
-pub fn add_duration(duration: Duration) {
-    try_with_thread_local_data(|data| {
-        data.duration += duration;
-    });
-}
-
-pub fn add_allocation_info(alloc_info: AllocationInfo) {
-    try_with_thread_local_data(|data| {
-        data.allocations += alloc_info.allocations;
-        data.deallocations += alloc_info.deallocations;
-    });
-}
-
 #[derive(Debug, Clone, Serialize, Deserialize, PartialEq, Eq)]
 pub struct TurboTasksPanic {
     pub message: TurboTasksExecutionErrorMessage,
@@ -93,21 +50,10 @@ impl Display for TurboTasksPanic {
 }
 
 impl<T, F: Future<Output = T>> Future for CaptureFuture<T, F> {
-    type Output = (Result<T, TurboTasksPanic>, Duration, AllocationInfo);
+    type Output = Result<T, TurboTasksPanic>;
 
     fn poll(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Self::Output> {
         let this = self.project();
-        let start = Instant::now();
-        let start_allocations = TurboMalloc::allocation_counters();
-        let guard = ThreadLocalDataDropGuard;
-        let mut data = ThreadLocalData {
-            duration: Duration::ZERO,
-            allocations: 0,
-            deallocations: 0,
-        };
-        EXTRA.with_borrow_mut(|cell| {
-            *cell = Some(&mut data as *mut ThreadLocalData);
-        });
 
         let result =
             panic::catch_unwind(panic::AssertUnwindSafe(|| this.future.poll(cx))).map_err(|err| {
@@ -132,25 +78,10 @@ impl<T, F: Future<Output = T>> Future for CaptureFuture<T, F> {
                 })
             });
 
-        drop(guard);
-        let elapsed = start.elapsed();
-        let allocations = start_allocations.until_now();
-        *this.duration += elapsed + data.duration;
-        *this.allocations += allocations;
         match result {
-            Err(err) => Poll::Ready((Err(err), *this.duration, this.allocations.clone())),
-            Ok(Poll::Ready(r)) => Poll::Ready((Ok(r), *this.duration, this.allocations.clone())),
+            Err(err) => Poll::Ready(Err(err)),
+            Ok(Poll::Ready(r)) => Poll::Ready(Ok(r)),
             Ok(Poll::Pending) => Poll::Pending,
         }
     }
 }
-
-struct ThreadLocalDataDropGuard;
-
-impl Drop for ThreadLocalDataDropGuard {
-    fn drop(&mut self) {
-        EXTRA.with_borrow_mut(|cell| {
-            *cell = None;
-        });
-    }
-}
diff --git a/turbopack/crates/turbo-tasks/src/manager.rs b/turbopack/crates/turbo-tasks/src/manager.rs
@@ -578,7 +578,7 @@ impl<B: Backend + 'static> TurboTasks<B> {
             .scope(
                 self.pin(),
                 CURRENT_TASK_STATE.scope(current_task_state, async {
-                    let (result, _duration, _alloc_info) = CaptureFuture::new(future).await;
+                    let result = CaptureFuture::new(future).await;
 
                     // wait for all spawned local tasks using `local` to finish
                     let ltt =
@@ -736,7 +736,7 @@ impl<B: Backend + 'static> TurboTasks<B> {
                     };
 
                     async {
-                        let (result, duration, alloc_info) = CaptureFuture::new(future).await;
+                        let result = CaptureFuture::new(future).await;
 
                         // wait for all spawned local tasks using `local` to finish
                         let ltt = CURRENT_TASK_STATE
@@ -758,8 +758,6 @@ impl<B: Backend + 'static> TurboTasks<B> {
                             .with(|ts| ts.write().unwrap().cell_counters.take().unwrap());
                         this.backend.task_execution_completed(
                             task_id,
-                            duration,
-                            alloc_info.memory_usage(),
                             result,
                             &cell_counters,
                             stateful,
@@ -835,7 +833,7 @@ impl<B: Backend + 'static> TurboTasks<B> {
             let TaskExecutionSpec { future, span } =
                 crate::task::local_task::get_local_task_execution_spec(&*this, &ty, persistence);
             async move {
-                let (result, _duration, _memory_usage) = CaptureFuture::new(future).await;
+                let result = CaptureFuture::new(future).await;
 
                 let result = match result {
                     Ok(Ok(raw_vc)) => Ok(raw_vc),
diff --git a/turbopack/crates/turbo-tasks/src/spawn.rs b/turbopack/crates/turbo-tasks/src/spawn.rs
@@ -3,24 +3,20 @@ use std::{
     pin::Pin,
     task::{Context, Poll},
     thread,
-    time::{Duration, Instant},
 };
 
 use anyhow::Result;
 use futures::{FutureExt, ready};
 use tokio::runtime::Handle;
 use tracing::{Instrument, Span, info_span};
-use turbo_tasks_malloc::{AllocationInfo, TurboMalloc};
 
 use crate::{
-    TurboTasksPanic,
-    capture_future::{self, CaptureFuture},
-    manager::turbo_tasks_future_scope,
-    turbo_tasks, turbo_tasks_scope,
+    TurboTasksPanic, capture_future::CaptureFuture, manager::turbo_tasks_future_scope, turbo_tasks,
+    turbo_tasks_scope,
 };
 
 pub struct JoinHandle<T> {
-    join_handle: tokio::task::JoinHandle<(Result<T, TurboTasksPanic>, Duration, AllocationInfo)>,
+    join_handle: tokio::task::JoinHandle<Result<T, TurboTasksPanic>>,
 }
 
 impl<T: Send + 'static> JoinHandle<T> {
@@ -35,14 +31,10 @@ impl<T> Future for JoinHandle<T> {
     fn poll(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Self::Output> {
         let this = self.get_mut();
         match ready!(this.join_handle.poll_unpin(cx)) {
-            Ok((res, duration, alloc_info)) => {
-                capture_future::add_duration(duration);
-                capture_future::add_allocation_info(alloc_info);
-                match res {
-                    Ok(res) => Poll::Ready(res),
-                    Err(e) => resume_unwind(e.into_panic()),
-                }
-            }
+            Ok(res) => match res {
+                Ok(res) => Poll::Ready(res),
+                Err(e) => resume_unwind(e.into_panic()),
+            },
             Err(e) => resume_unwind(e.into_panic()),
         }
     }
@@ -71,10 +63,7 @@ pub fn spawn_blocking<T: Send + 'static>(
     let span = Span::current();
     let join_handle = tokio::task::spawn_blocking(|| {
         let _guard = span.entered();
-        let start = Instant::now();
-        let start_allocations = TurboMalloc::allocation_counters();
-        let r = turbo_tasks_scope(turbo_tasks, func);
-        (Ok(r), start.elapsed(), start_allocations.until_now())
+        Ok(turbo_tasks_scope(turbo_tasks, func))
     });
     JoinHandle { join_handle }
 }
diff --git a/turbopack/crates/turbo-tasks/src/task_statistics.rs b/turbopack/crates/turbo-tasks/src/task_statistics.rs
@@ -46,17 +46,6 @@ impl TaskStatistics {
         self.with_task_type_statistics(native_fn, |stats| stats.cache_miss += 1)
     }
 
-    pub fn increment_execution_duration(
-        &self,
-        native_fn: &'static NativeFunction,
-        duration: std::time::Duration,
-    ) {
-        self.with_task_type_statistics(native_fn, |stats| {
-            stats.executions += 1;
-            stats.duration += duration
-        })
-    }
-
     fn with_task_type_statistics(
         &self,
         native_fn: &'static NativeFunction,
@@ -75,10 +64,6 @@ impl TaskStatistics {
 pub struct TaskFunctionStatistics {
     pub cache_hit: u32,
     pub cache_miss: u32,
-    // Generally executions == cache_miss, however they can diverge when there are invalidations.
-    // The caller gets one cache miss but we might execute multiple times.
-    pub executions: u32,
-    pub duration: std::time::Duration,
 }
 
 impl Serialize for TaskStatistics {
