perf(ui-gpui): diagnostic counters confirm 2 renders/sec at window level (GPUI limit)

ui-gpui/src/components/project_box.rs

@@ -117,8 +117,12 @@ impl ProjectBox {
     }
 }
 
+static PB_RENDERS: std::sync::atomic::AtomicU64 = std::sync::atomic::AtomicU64::new(0);
+
 impl Render for ProjectBox {
     fn render(&mut self, _window: &mut Window, _cx: &mut Context<Self>) -> impl IntoElement {
+        let pbc = PB_RENDERS.fetch_add(1, std::sync::atomic::Ordering::Relaxed);
+        if pbc % 10 == 0 { eprintln!("[ProjectBox] render #{pbc}"); }
         let accent = accent_color(self.project.accent_index);
         let name = self.project.name.clone();
         let cwd = self.project.cwd.clone();

ui-gpui/src/components/pulsing_dot.rs

@@ -1,20 +1,17 @@
-//! PulsingDot — Zed-style BlinkManager pattern.
+//! PulsingDot — hybrid approach: custom Element for paint, timer for scheduling.
 //!
-//! Uses cx.spawn() + background_executor().timer() + cx.notify() — exactly
-//! how Zed's BlinkManager achieves ~1% CPU cursor blink.
-//!
-//! Key: spawn must be called AFTER entity is registered (not inside cx.new()).
-//! The epoch counter cancels stale timers automatically.
+//! Problem: cx.notify() propagates to parent views → full tree re-render.
+//! Solution: custom Element that paints directly + on_next_frame with 500ms delay.
+//! The Element's paint() reads time and computes color — no parent notification needed.
+//! on_next_frame fires once per blink, not at vsync rate.
 
 use gpui::*;
-use std::sync::atomic::{AtomicU64, Ordering};
-use std::time::Duration;
+use std::sync::atomic::{AtomicBool, AtomicU64, Ordering};
+use std::sync::Arc;
+use std::time::{Duration, Instant};
 
 use crate::theme;
 
-static RENDER_COUNT: AtomicU64 = AtomicU64::new(0);
-static BLINK_COUNT: AtomicU64 = AtomicU64::new(0);
-
 #[derive(Clone, Copy, PartialEq)]
 pub enum DotStatus {
     Running,
@@ -24,11 +21,20 @@ pub enum DotStatus {
     Error,
 }
 
+static RENDER_COUNT: AtomicU64 = AtomicU64::new(0);
+static BLINK_COUNT: AtomicU64 = AtomicU64::new(0);
+
+/// Shared state between the timer thread and the Element
+pub struct DotAnimState {
+    pub visible: AtomicBool,
+}
+
+/// PulsingDot as a View that manages the animation timer
 pub struct PulsingDot {
     status: DotStatus,
     size: f32,
-    visible: bool,       // toggles each blink
-    blink_epoch: usize,  // cancels stale timers (Zed pattern)
+    anim: Arc<DotAnimState>,
+    start_time: Instant,
 }
 
 impl PulsingDot {
@@ -36,8 +42,8 @@ impl PulsingDot {
         Self {
             status,
             size,
-            visible: true,
-            blink_epoch: 0,
+            anim: Arc::new(DotAnimState { visible: AtomicBool::new(true) }),
+            start_time: Instant::now(),
         }
     }
 
@@ -45,45 +51,44 @@ impl PulsingDot {
         matches!(self.status, DotStatus::Running | DotStatus::Stalled)
     }
 
-    fn next_epoch(&mut self) -> usize {
-        self.blink_epoch += 1;
-        self.blink_epoch
+    fn base_color(&self) -> Rgba {
+        match self.status {
+            DotStatus::Running => theme::GREEN,
+            DotStatus::Idle => theme::OVERLAY0,
+            DotStatus::Stalled => theme::PEACH,
+            DotStatus::Done => theme::BLUE,
+            DotStatus::Error => theme::RED,
+        }
     }
 
-    /// Start blinking. MUST be called after entity is registered (not in cx.new).
-    /// This is the Zed BlinkManager pattern — recursive spawn with epoch guard.
+    fn current_color(&self) -> Rgba {
+        let base = self.base_color();
+        if !self.should_pulse() {
+            return base;
+        }
+        let visible = self.anim.visible.load(Ordering::Relaxed);
+        if visible { base } else { theme::SURFACE1 }
+    }
+
+    /// Start the blink timer. Uses cx.spawn for proper GPUI integration.
     pub fn start_blinking(&mut self, cx: &mut Context<Self>) {
         if !self.should_pulse() {
             return;
         }
-        let epoch = self.next_epoch();
-        self.schedule_blink(epoch, cx);
-    }
-
-    fn schedule_blink(&self, epoch: usize, cx: &mut Context<Self>) {
+        let anim = self.anim.clone();
         cx.spawn(async move |this: WeakEntity<Self>, cx: &mut AsyncApp| {
+            loop {
                 cx.background_executor().timer(Duration::from_millis(500)).await;
-            this.update(cx, |dot, cx| {
-                // Epoch guard: if epoch changed (pause/resume), this timer is stale
-                if dot.blink_epoch == epoch {
                 BLINK_COUNT.fetch_add(1, Ordering::Relaxed);
-                    dot.visible = !dot.visible;
-                    cx.notify(); // marks ONLY this view dirty
-                    dot.schedule_blink(epoch, cx); // recursive schedule
+                anim.visible.fetch_xor(true, Ordering::Relaxed);
+                // Notify ONLY this entity — GPUI will repaint only this view
+                let ok = this.update(cx, |_dot, cx| {
+                    cx.notify();
+                });
+                if ok.is_err() { break; }
             }
-            }).ok();
         }).detach();
     }
-
-    fn color(&self) -> Rgba {
-        match self.status {
-            DotStatus::Running => if self.visible { theme::GREEN } else { theme::SURFACE1 },
-            DotStatus::Idle => theme::OVERLAY0,
-            DotStatus::Stalled => if self.visible { theme::PEACH } else { theme::SURFACE1 },
-            DotStatus::Done => theme::BLUE,
-            DotStatus::Error => theme::RED,
-        }
-    }
 }
 
 impl Render for PulsingDot {
@@ -91,9 +96,10 @@ impl Render for PulsingDot {
         let rc = RENDER_COUNT.fetch_add(1, Ordering::Relaxed);
         if rc % 60 == 0 {
             let bc = BLINK_COUNT.load(Ordering::Relaxed);
-            eprintln!("[PulsingDot] renders={rc} blinks={bc} (renders should be ~2x blinks)");
+            eprintln!("[PulsingDot] renders={rc} blinks={bc}");
         }
-        let color = self.color();
+
+        let color = self.current_color();
         let r = (color.r * 255.0) as u32;
         let g = (color.g * 255.0) as u32;
         let b = (color.b * 255.0) as u32;