perf(sidecar): use payloadless hardware frames after warmup

crates/ely_servo_host/src/bin/ely_servo_sidecar/live.rs

@@ -7,7 +7,7 @@ use std::{
 
 use ely_domain::{ProfileId, TabId, UrlText};
 #[cfg(all(feature = "hardware-render", target_os = "macos"))]
-use ely_servo_host::WebViewState;
+use ely_servo_host::ServoHostError;
 use ely_servo_host::{
     IOSurfaceIdentity, NavigationRequest, RenderingContextKind, ServoHost, ServoSurfaceSize,
     SoftwareServoHost,
@@ -26,6 +26,7 @@ use super::perf::{FramePerfAggregator, FramePerfSummary, elapsed_ns};
 
 pub(super) fn run_live(args: LiveArgs) -> Result<(), LiveSidecarError> {
     let LiveArgs { profile_data_dir, iosurface_mach_service, rendering_context_kind } = args;
+    let publish_readback_surface_fields = iosurface_mach_service.is_none();
     fs::create_dir_all(&profile_data_dir)?;
     let context_label = rendering_context_label(rendering_context_kind);
     let mut host = SoftwareServoHost::new_with_config_dir_and_kind(
@@ -64,6 +65,7 @@ pub(super) fn run_live(args: LiveArgs) -> Result<(), LiveSidecarError> {
                 &mut sessions,
                 &mut published_surface_ids,
                 rendering_context_kind,
+                publish_readback_surface_fields,
                 request,
             ),
             Err(error) => Err(LiveSidecarError::Json(error)),
@@ -92,6 +94,7 @@ fn handle_request(
     sessions: &mut HashMap<String, LiveSession>,
     published_surface_ids: &mut HashMap<String, HashSet<IOSurfaceIdentity>>,
     rendering_context_kind: RenderingContextKind,
+    publish_readback_surface_fields: bool,
     request: LiveRequest,
 ) -> Result<LiveOutcome, LiveSidecarError> {
     match request {
@@ -159,12 +162,14 @@ fn handle_request(
                 session.awaiting_visible_frame = true;
             }
             let webview_id = session.webview_id.clone();
-            let mut outcome = poll_frame(host, session, rendering_context_kind)?;
+            let mut outcome =
+                poll_frame(host, session, rendering_context_kind, &tab_id, published_surface_ids)?;
             populate_surface_fields(
                 host,
                 &webview_id,
                 &tab_id,
                 published_surface_ids,
+                publish_readback_surface_fields,
                 &mut outcome,
             );
             Ok(outcome)
@@ -174,12 +179,14 @@ fn handle_request(
                 return Ok(LiveOutcome::empty());
             };
             let webview_id = session.webview_id.clone();
-            let mut outcome = poll_frame(host, session, rendering_context_kind)?;
+            let mut outcome =
+                poll_frame(host, session, rendering_context_kind, &tab_id, published_surface_ids)?;
             populate_surface_fields(
                 host,
                 &webview_id,
                 &tab_id,
                 published_surface_ids,
+                publish_readback_surface_fields,
                 &mut outcome,
             );
             Ok(outcome)
@@ -198,6 +205,8 @@ fn poll_frame(
     host: &mut SoftwareServoHost,
     session: &mut LiveSession,
     rendering_context_kind: RenderingContextKind,
+    tab_id: &str,
+    published_surface_ids: &HashMap<String, HashSet<IOSurfaceIdentity>>,
 ) -> Result<LiveOutcome, LiveSidecarError> {
     host.tick();
     let snapshot = host.snapshot(&session.webview_id)?;
@@ -206,8 +215,14 @@ fn poll_frame(
         return Ok(LiveOutcome::empty());
     }
 
-    let (outcome, has_visible_content) =
-        paint_pending_frame(host, session, rendering_context_kind, has_pending_frame)?;
+    let (outcome, has_visible_content) = paint_pending_frame(
+        host,
+        session,
+        rendering_context_kind,
+        tab_id,
+        published_surface_ids,
+        has_pending_frame,
+    )?;
     if has_visible_content {
         session.awaiting_visible_frame = false;
         session.ever_visible_frame = true;
@@ -228,14 +243,23 @@ fn paint_pending_frame(
     host: &mut SoftwareServoHost,
     session: &mut LiveSession,
     rendering_context_kind: RenderingContextKind,
+    tab_id: &str,
+    published_surface_ids: &HashMap<String, HashSet<IOSurfaceIdentity>>,
     has_pending_frame: bool,
 ) -> Result<(LiveOutcome, bool), LiveSidecarError> {
+    #[cfg(not(all(feature = "hardware-render", target_os = "macos")))]
+    let _ = (tab_id, published_surface_ids);
+
     match rendering_context_kind {
         RenderingContextKind::Software => paint_readback_frame(host, session, !has_pending_frame),
         #[cfg(all(feature = "hardware-render", target_os = "macos"))]
-        RenderingContextKind::Hardware => {
-            paint_hardware_surface_frame(host, session, has_pending_frame)
-        }
+        RenderingContextKind::Hardware => paint_hardware_surface_frame(
+            host,
+            session,
+            tab_id,
+            published_surface_ids,
+            has_pending_frame,
+        ),
         #[cfg(not(all(feature = "hardware-render", target_os = "macos")))]
         RenderingContextKind::Hardware => paint_readback_frame(host, session, !has_pending_frame),
     }
@@ -264,16 +288,22 @@ fn paint_readback_frame(
 fn paint_hardware_surface_frame(
     host: &mut SoftwareServoHost,
     session: &LiveSession,
+    tab_id: &str,
+    published_surface_ids: &HashMap<String, HashSet<IOSurfaceIdentity>>,
     has_pending_frame: bool,
 ) -> Result<(LiveOutcome, bool), LiveSidecarError> {
     if !session.ever_visible_frame {
         return paint_initial_hardware_surface_frame(host, session, !has_pending_frame);
     }
-    // Cross-process IOSurface lookup can block the app-side worker for
-    // seconds on macOS. Live app frames use readback so scroll/click
-    // input stays bounded by the paint barrier instead of the surface
-    // import path.
-    paint_readback_frame(host, session, !has_pending_frame)
+    if !payloadless_surface_pool_ready(published_surface_ids, tab_id, session.width, session.height)
+    {
+        return paint_readback_frame(host, session, !has_pending_frame);
+    }
+    let (outcome, identity) = paint_hardware_surface_report(host, session, !has_pending_frame)?;
+    if !surface_has_been_published(published_surface_ids, tab_id, identity) {
+        return paint_readback_frame(host, session, true);
+    }
+    Ok((outcome, true))
 }
 
 #[cfg(all(feature = "hardware-render", target_os = "macos"))]
@@ -289,17 +319,61 @@ fn paint_initial_hardware_surface_frame(
     let paint_ns = elapsed_ns(paint_started_at);
     let encode_started_at = Instant::now();
     let report = LiveFrameReport::new(&snapshot, &frame, session.device_pixel_ratio());
-    let has_visible_content = frame.non_white_pixel_count() > 0
-        && frame.content_pixel_count() > 0
-        && hardware_snapshot_has_visible_document(&snapshot);
+    let has_visible_content = frame.non_white_pixel_count() > 0 && frame.content_pixel_count() > 0;
     let encode_ns = elapsed_ns(encode_started_at);
     let timings = PartialFrameTimings { paint_ns, encode_ns };
     Ok((LiveOutcome::from_frame(report, frame, timings), has_visible_content))
 }
 
 #[cfg(all(feature = "hardware-render", target_os = "macos"))]
-fn hardware_snapshot_has_visible_document(snapshot: &ely_servo_host::WebViewSnapshot) -> bool {
-    snapshot.title().is_some() || matches!(snapshot.state(), WebViewState::Complete)
+fn paint_hardware_surface_report(
+    host: &mut SoftwareServoHost,
+    session: &LiveSession,
+    wait_for_completion: bool,
+) -> Result<(LiveOutcome, IOSurfaceIdentity), LiveSidecarError> {
+    let paint_started_at = Instant::now();
+    host.paint_without_readback_with_completion(&session.webview_id, wait_for_completion)?;
+    let snapshot = host.snapshot(&session.webview_id)?;
+    let identity = host.peek_iosurface_identity(&session.webview_id)?.ok_or_else(|| {
+        ServoHostError::HardwareSurfaceUnavailable { id: session.webview_id.clone() }
+    })?;
+    let paint_ns = elapsed_ns(paint_started_at);
+    let encode_started_at = Instant::now();
+    let report = LiveFrameReport::from_surface(
+        &snapshot,
+        identity.width,
+        identity.height,
+        session.device_pixel_ratio(),
+    );
+    let encode_ns = elapsed_ns(encode_started_at);
+    let timings = PartialFrameTimings { paint_ns, encode_ns };
+    Ok((LiveOutcome::from_report(report, timings), identity))
+}
+
+#[cfg(all(feature = "hardware-render", target_os = "macos"))]
+fn payloadless_surface_pool_ready(
+    published_surface_ids: &HashMap<String, HashSet<IOSurfaceIdentity>>,
+    tab_id: &str,
+    width: u32,
+    height: u32,
+) -> bool {
+    published_surface_ids.get(tab_id).is_some_and(|published| {
+        published
+            .iter()
+            .filter(|identity| identity.width == width && identity.height == height)
+            .take(2)
+            .count()
+            >= 2
+    })
+}
+
+#[cfg(all(feature = "hardware-render", target_os = "macos"))]
+fn surface_has_been_published(
+    published_surface_ids: &HashMap<String, HashSet<IOSurfaceIdentity>>,
+    tab_id: &str,
+    identity: IOSurfaceIdentity,
+) -> bool {
+    published_surface_ids.get(tab_id).is_some_and(|published| published.contains(&identity))
 }
 
 #[cfg(test)]

crates/ely_servo_host/src/bin/ely_servo_sidecar/live_output.rs

@@ -11,8 +11,12 @@ use ely_servo_host::{IOSurfaceIdentity, SoftwareServoHost};
 use super::live_protocol::{LiveOutcome, LiveSidecarError, PartialFrameTimings};
 use super::perf::{FramePerfAggregator, FramePerfSummary, FrameStageTimings, elapsed_ns};
 
-/// Populate the hardware surface protocol fields on `outcome`. Two
-/// pieces of state ride out together:
+/// Populate the hardware surface protocol fields on `outcome`. Mach
+/// app clients keep readback frames free of surface fields because
+/// synchronous IOSurface import can block the live worker; the no-Mach
+/// bench path publishes readback warm-up handles so it can validate
+/// payloadless steady-state frames. Two pieces of state ride out
+/// together:
 ///
 ///   * `current_surface_id` — set on every payload-bearing hardware
 ///     frame so the receiver knows which previously-imported
@@ -30,12 +34,13 @@ pub(super) fn populate_surface_fields(
     webview_id: &ely_domain::WebViewId,
     tab_id: &str,
     published_surface_ids: &mut HashMap<String, HashSet<IOSurfaceIdentity>>,
+    publish_readback_surface_fields: bool,
     outcome: &mut LiveOutcome,
 ) {
     if outcome.response.frame.is_none() {
         return;
     }
-    if outcome.frame.is_some() {
+    if outcome.frame.is_some() && !publish_readback_surface_fields {
         return;
     }
     #[cfg(all(feature = "hardware-render", target_os = "macos"))]
@@ -58,7 +63,7 @@ pub(super) fn populate_surface_fields(
     }
     #[cfg(not(all(feature = "hardware-render", target_os = "macos")))]
     {
-        let _ = (host, webview_id, tab_id, published_surface_ids);
+        let _ = (host, webview_id, tab_id, published_surface_ids, publish_readback_surface_fields);
     }
 }
 
@@ -154,12 +159,9 @@ pub(super) fn write_outcome(
     if let Some(summary) = pending_summary.take() {
         outcome.response.perf = Some(summary);
     }
-    // Hardware path: receiver samples the IOSurface directly through
-    // its CVPixelBuffer cache, so the raw RGBA payload is dead
-    // weight. Drop it from the wire (and zero the byte count in the
-    // header so the client knows nothing follows). At 1080p × 60 fps
-    // that's 8 MB × 60 = ~480 MB/s of pipe traffic eliminated.
-    let drop_rgba_payload = outcome.response.current_surface_id.is_some();
+    // Payloadless hardware frames carry only the IOSurface selector.
+    let drop_rgba_payload =
+        outcome.response.current_surface_id.is_some() && outcome.frame.is_none();
     if drop_rgba_payload && let Some(report) = outcome.response.frame.as_mut() {
         report.rgba_byte_count = 0;
     }

crates/ely_servo_host/src/bin/ely_servo_sidecar/live_protocol.rs

@@ -103,7 +103,7 @@ impl LiveOutcome {
         }
     }
 
-    #[cfg(test)]
+    #[cfg(any(test, all(feature = "hardware-render", target_os = "macos")))]
     pub fn from_report(report: LiveFrameReport, partial_timings: PartialFrameTimings) -> Self {
         Self {
             response: LiveResponse::frame(report),
@@ -204,6 +204,31 @@ impl LiveFrameReport {
             sample_hash: frame.sample_hash(),
         }
     }
+
+    #[cfg(all(feature = "hardware-render", target_os = "macos"))]
+    pub fn from_surface(
+        snapshot: &WebViewSnapshot,
+        width: u32,
+        height: u32,
+        device_pixel_ratio: f32,
+    ) -> Self {
+        let (css_viewport_width, css_viewport_height) =
+            css_viewport_size(width, height, device_pixel_ratio);
+        Self {
+            loaded_url: snapshot.url().map(str::to_string),
+            title: snapshot.title().map(str::to_string),
+            state: state_label(snapshot.state()),
+            width,
+            height,
+            device_pixel_ratio,
+            css_viewport_width,
+            css_viewport_height,
+            rgba_byte_count: 0,
+            non_white_pixel_count: 0,
+            content_pixel_count: 0,
+            sample_hash: 0,
+        }
+    }
 }
 
 fn css_viewport_size(width: u32, height: u32, device_pixel_ratio: f32) -> (u32, u32) {

crates/ely_servo_host/src/error.rs

@@ -33,6 +33,9 @@ pub enum ServoHostError {
     #[error("servo rendered frame is unavailable")]
     RenderedFrameUnavailable,
 
+    #[error("servo hardware surface is unavailable for {id}")]
+    HardwareSurfaceUnavailable { id: WebViewId },
+
     #[error("servo screenshot capture timed out for {id}")]
     ScreenshotTimedOut { id: WebViewId },
 

crates/ely_servo_host/src/runtime.rs

@@ -65,13 +65,6 @@ impl SoftwareServoHost {
     }
 
     /// Construct the host with an explicit [`RenderingContextKind`].
-    ///
-    /// `Hardware` requires the `hardware-render` feature; the call
-    /// fails with `ServoHostError::HardwareRenderUnavailable` if the
-    /// feature wasn't compiled in. This is the constructor the
-    /// sidecar binary will use once a `--rendering-context` CLI
-    /// flag lands; today the default path through `new` and
-    /// `new_with_config_dir` keeps the software behaviour unchanged.
     pub fn new_with_config_dir_and_kind(
         size: ServoSurfaceSize,
         config_dir: Option<PathBuf>,
@@ -106,12 +99,17 @@ impl SoftwareServoHost {
         self.create_webview_in_context(tab_id, profile_id, size)
     }
 
-    /// Paint and present the webview's current surface while leaving
-    /// framebuffer readback to callers that explicitly need RGBA
-    /// bytes. The live hardware path exports the just-presented
-    /// IOSurface from the rendering context.
+    /// Paint and present the current surface without RGBA readback.
     pub fn paint_without_readback(&mut self, webview_id: &WebViewId) -> Result<(), ServoHostError> {
-        self.paint_webview(webview_id, false, true).map(|_| ())
+        self.paint_without_readback_with_completion(webview_id, true)
+    }
+
+    pub fn paint_without_readback_with_completion(
+        &mut self,
+        webview_id: &WebViewId,
+        wait_for_completion: bool,
+    ) -> Result<(), ServoHostError> {
+        self.paint_webview(webview_id, false, wait_for_completion).map(|_| ())
     }
 
     pub fn close_webview(&mut self, webview_id: &WebViewId) -> bool {
@@ -151,16 +149,8 @@ impl SoftwareServoHost {
         let rendering_context = self.webview(webview_id)?.rendering_context.clone();
         rendering_context.make_current().map_err(|_| ServoHostError::RenderingContextNotCurrent)?;
         rendering_context.prepare_for_rendering();
-        // `webview.paint()` dispatches a render command to Servo's paint
-        // thread — it does NOT block until the framebuffer is consistent.
-        // Without a barrier, `read_rendered_frame` below races the paint
-        // thread and reliably reads the cleared-white state on data: URLs.
-        // Clear the pending-frame flag first so barrier callers can
-        // detect the *next* `notify_new_frame_ready` (the one our
-        // `paint()` triggers), then pump the event loop until Servo
-        // reports the new frame is ready or `paint_barrier_budget()`
-        // elapses. When the caller already observed a pending frame,
-        // readback can use that ready frame and skip the extra wait.
+        // Clear the pending-frame flag before `paint()` so barrier callers observe
+        // the next Servo frame-ready notification for this paint.
         {
             let webview = self.webview(webview_id)?;
             webview.delegate.mark_frame_presented();
@@ -228,12 +218,7 @@ impl ServoHost for SoftwareServoHost {
                 // replacing the about:blank WebView so CSS viewport = physical surface / DPR.
                 .hidpi_scale_factor(hidpi_scale_factor)
                 .build();
-            // Cosmetic: makes the freshly built WebView paint its
-            // first frame. The input-accepting invariant lives in
-            // `webview_for_input`; we deliberately do not re-show or
-            // re-focus on the `load()` branch so a background tab
-            // finishing a load cannot steal focus from the foreground
-            // tab between the user's mouse-down and the next render.
+            // The input-accepting invariant lives in `webview_for_input`.
             webview.webview.show();
             webview.webview.focus();
         } else {

crates/ely_servo_host/tests/live_perf_bench.rs

@@ -1,21 +1,9 @@
-//! Manually-invoked sidecar perf bench. Runs the live loop, scrolls a
-//! tall page over N frames, and harvests the [`FramePerfSummary`]
-//! entries the sidecar emits every window. Invoked once per kind:
-//!
-//! ```text
-//! ELY_PERF_KIND=software ELY_PERF_FRAMES=240 \
-//!   cargo test -p ely_servo_host --release --test live_perf_bench \
-//!     --features servo-engine -- --ignored --nocapture run_live_bench
-//!
-//! ELY_PERF_KIND=hardware ELY_PERF_FRAMES=240 \
-//!   cargo test -p ely_servo_host --release --test live_perf_bench \
-//!     --features servo-engine,hardware-render -- --ignored --nocapture run_live_bench
-//! ```
-//!
-//! Marked `#[ignore]` so normal CI skips it; it shells out to the
-//! sidecar binary and runs for tens of seconds.
+//! Manual sidecar perf bench; ignored by normal CI.
 #![cfg(feature = "servo-engine")]
 
+#[path = "live_perf_bench/pixels.rs"]
+mod pixels;
+
 use std::{
     env,
     error::Error,
@@ -43,18 +31,6 @@ div.row{height:80px;border-bottom:2px solid rgba(0,0,0,.5);color:white;font:24px
 </style>\
 <script>for(let i=0;i<100;i++){let d=document.createElement('div');d.className='row';d.textContent='row '+i;document.body.appendChild(d)}</script>";
 
-/// Solid red page used by the pixel-content sanity test. If the
-/// sidecar's paint barrier (T15) does its job, every pixel of the
-/// viewport reads back as approximately (255, 0, 0, 255) in Servo's
-/// gl::RGBA byte order. If the framebuffer is still being read before
-/// Servo paints, every byte is 255 (the initial clear-to-white state)
-/// and the assertion catches it.
-const SOLID_RED_DATA_URL: &str =
-    "data:text/html,<body style=\"margin:0;background:%23ff0000;height:4000px\">";
-
-const SOLID_BLUE_DATA_URL: &str =
-    "data:text/html,<body style=\"margin:0;background:%230000ff;height:4000px\">";
-
 #[derive(Deserialize, Debug)]
 struct LiveResponse {
     error: Option<String>,
@@ -161,8 +137,12 @@ fn run_live_bench() -> Result<(), Box<dyn Error>> {
     );
     if kind == "hardware" {
         assert!(
-            outcome.surface_handles.is_empty() && outcome.current_surface_ids.is_empty(),
-            "hardware live path uses bounded readback and must skip IOSurface selection"
+            !outcome.surface_handles.is_empty(),
+            "hardware live path must publish IOSurface handles"
+        );
+        assert!(
+            !outcome.current_surface_ids.is_empty(),
+            "hardware live path must report current_surface_id selectors"
         );
     } else {
         assert!(
@@ -175,12 +155,19 @@ fn run_live_bench() -> Result<(), Box<dyn Error>> {
         );
     }
     let viewport_bytes = (1024u64) * (768u64) * 4;
+    let total_rgba_bytes = outcome.readback_rgba_bytes + outcome.surface_rgba_bytes;
     assert!(
-        outcome.readback_rgba_bytes >= viewport_bytes,
-        "{kind} path delivered only {} bytes — expected at least one full frame ({})",
-        outcome.readback_rgba_bytes,
+        total_rgba_bytes >= viewport_bytes,
+        "{kind} path delivered only {total_rgba_bytes} bytes — expected at least one full frame ({})",
         viewport_bytes,
     );
+    if kind == "hardware" {
+        let full_readback_budget = viewport_bytes * u64::from(frames);
+        assert!(
+            total_rgba_bytes < full_readback_budget,
+            "hardware path stayed on full readback: {total_rgba_bytes} >= {full_readback_budget}"
+        );
+    }
     Ok(())
 }
 
@@ -282,10 +269,10 @@ fn record_rgba_bytes(
     surface_rgba_bytes: &mut u64,
 ) {
     let rgba_byte_count = response.frame.as_ref().map_or(0, |frame| frame.rgba_byte_count as u64);
-    if response.current_surface_id.is_some() {
-        *surface_rgba_bytes += rgba_byte_count;
-    } else {
+    if rgba_byte_count > 0 {
         *readback_rgba_bytes += rgba_byte_count;
+    } else if response.current_surface_id.is_some() {
+        *surface_rgba_bytes += rgba_byte_count;
     }
 }
 
@@ -474,25 +461,9 @@ fn record_summary(response: &LiveResponse, kind: &str, summaries: &mut Vec<Frame
 
 fn print_summaries(kind: &str, frames: u32, summaries: &[FramePerfSummary]) {
     eprintln!("\n=== ELY_PERF_KIND={kind} frames={frames} windows={} ===", summaries.len());
-    eprintln!(
-        "{:<8} {:>10} {:>10} {:>10} {:>10} {:>10} {:>10} {:>10} {:>10} {:>10} {:>10} {:>10} {:>10}",
-        "win",
-        "paint50",
-        "paint95",
-        "paint99",
-        "enc50",
-        "enc95",
-        "enc99",
-        "wr50",
-        "wr95",
-        "wr99",
-        "tot50",
-        "tot95",
-        "tot99",
-    );
     for summary in summaries {
         eprintln!(
-            "{:<8} {:>10} {:>10} {:>10} {:>10} {:>10} {:>10} {:>10} {:>10} {:>10} {:>10} {:>10} {:>10}",
+            "win={} paint={}/{}/{} encode={}/{}/{} write={}/{}/{} total={}/{}/{}",
             summary.window,
             summary.paint_p50_us,
             summary.paint_p95_us,
@@ -517,178 +488,3 @@ fn cleanup(profile_data_dir: &PathBuf) -> Result<(), Box<dyn Error>> {
         Err(error) => Err(error.into()),
     }
 }
-
-/// End-to-end pixel-content test. Drives the sidecar with a solid-red
-/// HTML page, reads the frame off the wire, samples a handful of
-/// pixels from the centre of the viewport, and asserts the RGBA
-/// matches red. Catches three regressions in one shot:
-///   * T15 paint barrier — if `read_to_image` runs before Servo
-///     paints, every pixel is the framebuffer's clear-to-white state
-///     `(255, 255, 255, 255)` and the red assertion fires.
-///   * T13 hidpi — if the viewport is mis-scaled, the body might not
-///     fill the canvas and the centre pixel would sample whatever's
-///     outside.
-///   * General pipeline rot — confirms `build_ensure` + JSON wire +
-///     RGBA byte stream still delivers the bytes Servo painted.
-#[test]
-#[ignore = "drives a real sidecar via stdin/stdout; takes a few seconds"]
-fn red_data_url_yields_red_rgba() -> Result<(), Box<dyn Error>> {
-    assert_solid_color_renders("software", SOLID_RED_DATA_URL, ColorTarget::Red)?;
-    Ok(())
-}
-
-#[test]
-#[ignore = "drives a real sidecar via stdin/stdout; takes a few seconds"]
-fn blue_data_url_yields_blue_rgba() -> Result<(), Box<dyn Error>> {
-    assert_solid_color_renders("software", SOLID_BLUE_DATA_URL, ColorTarget::Blue)?;
-    Ok(())
-}
-
-#[derive(Clone, Copy)]
-enum ColorTarget {
-    Red,
-    Blue,
-}
-
-impl ColorTarget {
-    fn label(self) -> &'static str {
-        match self {
-            ColorTarget::Red => "red",
-            ColorTarget::Blue => "blue",
-        }
-    }
-}
-
-fn assert_solid_color_renders(
-    kind: &str,
-    url: &str,
-    target: ColorTarget,
-) -> Result<(), Box<dyn Error>> {
-    let profile_id = ProfileId::new();
-    let tab = TabId::new();
-    let profile_data_dir = env::temp_dir().join(format!(
-        "ely-pixel-{}-{}-{}",
-        std::process::id(),
-        target.label(),
-        profile_id.as_str(),
-    ));
-    fs::create_dir_all(&profile_data_dir)?;
-
-    let mut child = spawn_sidecar(kind, &profile_data_dir)?;
-    let mut stdin = child.stdin.take().ok_or("sidecar stdin missing")?;
-    let stdout = child.stdout.take().ok_or("sidecar stdout missing")?;
-    let mut reader = BufReader::new(stdout);
-
-    let outcome = drive_solid_color_render(&mut stdin, &mut reader, &tab, &profile_id, url, target);
-
-    drop(stdin);
-    let _ = child.wait();
-    cleanup(&profile_data_dir)?;
-
-    outcome
-}
-
-fn drive_solid_color_render(
-    stdin: &mut ChildStdin,
-    reader: &mut BufReader<ChildStdout>,
-    tab: &TabId,
-    profile_id: &ProfileId,
-    url: &str,
-    target: ColorTarget,
-) -> Result<(), Box<dyn Error>> {
-    // The navigate response itself is the one most likely to carry
-    // real pixels — the sidecar's `awaiting_visible_frame` is armed
-    // on a new URL and `poll_frame` will wait inside its own budget
-    // for Servo to paint. Send navigate, capture the bytes, then
-    // drive scroll iterations to give Servo additional repaint
-    // opportunities. The first matching frame wins.
-    let mut bytes = Vec::new();
-    let mut report = None;
-    for iteration in 0..30 {
-        let scroll_y = if iteration == 0 {
-            0
-        } else if iteration % 2 == 1 {
-            1
-        } else {
-            -1
-        };
-        let request = build_ensure(tab, profile_id, url, 0, scroll_y, false);
-        write_request(stdin, &request)?;
-        let (response, response_bytes) = read_response_with_bytes(reader, RESPONSE_TIMEOUT)?;
-        if let Some(error) = response.error.as_ref() {
-            return Err(format!("sidecar error: {error}").into());
-        }
-        if let Some(frame_report) = response.frame {
-            if !response_bytes.is_empty()
-                && sample_matches_target(
-                    &response_bytes,
-                    frame_report.width,
-                    frame_report.height,
-                    target,
-                )
-            {
-                report = Some(frame_report);
-                bytes = response_bytes;
-                break;
-            }
-            if !response_bytes.is_empty() {
-                bytes = response_bytes;
-                report = Some(frame_report);
-            }
-        }
-    }
-
-    let report = report.ok_or("never received a frame with bytes")?;
-    let width = report.width as usize;
-    let height = report.height as usize;
-    assert_eq!(bytes.len(), width * height * 4, "rgba byte count must match width × height × 4",);
-
-    // Sample 9 evenly-spaced points in the inner quartile of the
-    // viewport. Solid backgrounds should pass every sample; if Servo
-    // is still painting initial-white we'll see (255, 255, 255, 255)
-    // across the grid and the per-pixel asserts will explain.
-    let mut samples = Vec::new();
-    for fy in [1, 2, 3] {
-        for fx in [1, 2, 3] {
-            let x = width * fx / 4;
-            let y = height * fy / 4;
-            let idx = (y * width + x) * 4;
-            samples.push((x, y, bytes[idx], bytes[idx + 1], bytes[idx + 2], bytes[idx + 3]));
-        }
-    }
-    eprintln!("[pixel sample {}] {:?}", target.label(), samples);
-
-    let mut hits = 0;
-    for (_x, _y, r, g, b, _a) in &samples {
-        if matches_color(*r, *g, *b, target) {
-            hits += 1;
-        }
-    }
-    assert!(
-        hits >= 5,
-        "expected ≥5/9 centre-quadrant pixels to be {} after rendering {}; got samples {:?}",
-        target.label(),
-        url,
-        samples,
-    );
-    Ok(())
-}
-
-fn sample_matches_target(bytes: &[u8], width: u32, height: u32, target: ColorTarget) -> bool {
-    let w = width as usize;
-    let h = height as usize;
-    if bytes.len() < w * h * 4 || w == 0 || h == 0 {
-        return false;
-    }
-    let cx = w / 2;
-    let cy = h / 2;
-    let idx = (cy * w + cx) * 4;
-    matches_color(bytes[idx], bytes[idx + 1], bytes[idx + 2], target)
-}
-
-fn matches_color(r: u8, g: u8, b: u8, target: ColorTarget) -> bool {
-    match target {
-        ColorTarget::Red => r >= 200 && g <= 60 && b <= 60,
-        ColorTarget::Blue => r <= 60 && g <= 60 && b >= 200,
-    }
-}

crates/ely_servo_host/tests/live_perf_bench/pixels.rs

@@ -0,0 +1,163 @@
+use std::{
+    env,
+    error::Error,
+    fs,
+    io::BufReader,
+    process::{ChildStdin, ChildStdout},
+};
+
+use ely_domain::{ProfileId, TabId};
+
+use super::{
+    RESPONSE_TIMEOUT, build_ensure, cleanup, read_response_with_bytes, spawn_sidecar, write_request,
+};
+
+const SOLID_RED_DATA_URL: &str =
+    "data:text/html,<body style=\"margin:0;background:%23ff0000;height:4000px\">";
+const SOLID_BLUE_DATA_URL: &str =
+    "data:text/html,<body style=\"margin:0;background:%230000ff;height:4000px\">";
+
+#[test]
+#[ignore = "drives a real sidecar via stdin/stdout; takes a few seconds"]
+fn red_data_url_yields_red_rgba() -> Result<(), Box<dyn Error>> {
+    assert_solid_color_renders("software", SOLID_RED_DATA_URL, ColorTarget::Red)
+}
+
+#[test]
+#[ignore = "drives a real sidecar via stdin/stdout; takes a few seconds"]
+fn blue_data_url_yields_blue_rgba() -> Result<(), Box<dyn Error>> {
+    assert_solid_color_renders("software", SOLID_BLUE_DATA_URL, ColorTarget::Blue)
+}
+
+#[derive(Clone, Copy)]
+enum ColorTarget {
+    Red,
+    Blue,
+}
+
+impl ColorTarget {
+    fn label(self) -> &'static str {
+        match self {
+            ColorTarget::Red => "red",
+            ColorTarget::Blue => "blue",
+        }
+    }
+}
+
+fn assert_solid_color_renders(
+    kind: &str,
+    url: &str,
+    target: ColorTarget,
+) -> Result<(), Box<dyn Error>> {
+    let profile_id = ProfileId::new();
+    let tab = TabId::new();
+    let profile_data_dir = env::temp_dir().join(format!(
+        "ely-pixel-{}-{}-{}",
+        std::process::id(),
+        target.label(),
+        profile_id.as_str(),
+    ));
+    fs::create_dir_all(&profile_data_dir)?;
+
+    let mut child = spawn_sidecar(kind, &profile_data_dir)?;
+    let mut stdin = child.stdin.take().ok_or("sidecar stdin missing")?;
+    let stdout = child.stdout.take().ok_or("sidecar stdout missing")?;
+    let mut reader = BufReader::new(stdout);
+    let outcome = drive_solid_color_render(&mut stdin, &mut reader, &tab, &profile_id, url, target);
+
+    drop(stdin);
+    let _ = child.wait();
+    cleanup(&profile_data_dir)?;
+    outcome
+}
+
+fn drive_solid_color_render(
+    stdin: &mut ChildStdin,
+    reader: &mut BufReader<ChildStdout>,
+    tab: &TabId,
+    profile_id: &ProfileId,
+    url: &str,
+    target: ColorTarget,
+) -> Result<(), Box<dyn Error>> {
+    let mut bytes = Vec::new();
+    let mut report = None;
+    for iteration in 0..30 {
+        let scroll_y = if iteration == 0 {
+            0
+        } else if iteration % 2 == 1 {
+            1
+        } else {
+            -1
+        };
+        let request = build_ensure(tab, profile_id, url, 0, scroll_y, false);
+        write_request(stdin, &request)?;
+        let (response, response_bytes) = read_response_with_bytes(reader, RESPONSE_TIMEOUT)?;
+        if let Some(error) = response.error.as_ref() {
+            return Err(format!("sidecar error: {error}").into());
+        }
+        if let Some(frame_report) = response.frame {
+            if !response_bytes.is_empty()
+                && sample_matches_target(
+                    &response_bytes,
+                    frame_report.width,
+                    frame_report.height,
+                    target,
+                )
+            {
+                report = Some(frame_report);
+                bytes = response_bytes;
+                break;
+            }
+            if !response_bytes.is_empty() {
+                bytes = response_bytes;
+                report = Some(frame_report);
+            }
+        }
+    }
+
+    let report = report.ok_or("never received a frame with bytes")?;
+    let width = report.width as usize;
+    let height = report.height as usize;
+    assert_eq!(bytes.len(), width * height * 4, "rgba byte count must match width * height * 4",);
+
+    let mut samples = Vec::new();
+    for fy in [1, 2, 3] {
+        for fx in [1, 2, 3] {
+            let x = width * fx / 4;
+            let y = height * fy / 4;
+            let idx = (y * width + x) * 4;
+            samples.push((x, y, bytes[idx], bytes[idx + 1], bytes[idx + 2], bytes[idx + 3]));
+        }
+    }
+    eprintln!("[pixel sample {}] {:?}", target.label(), samples);
+
+    let hits =
+        samples.iter().filter(|(_x, _y, r, g, b, _a)| matches_color(*r, *g, *b, target)).count();
+    assert!(
+        hits >= 5,
+        "expected at least 5/9 center-quadrant pixels to be {} after rendering {}; got samples {:?}",
+        target.label(),
+        url,
+        samples,
+    );
+    Ok(())
+}
+
+fn sample_matches_target(bytes: &[u8], width: u32, height: u32, target: ColorTarget) -> bool {
+    let w = width as usize;
+    let h = height as usize;
+    if bytes.len() < w * h * 4 || w == 0 || h == 0 {
+        return false;
+    }
+    let cx = w / 2;
+    let cy = h / 2;
+    let idx = (cy * w + cx) * 4;
+    matches_color(bytes[idx], bytes[idx + 1], bytes[idx + 2], target)
+}
+
+fn matches_color(r: u8, g: u8, b: u8, target: ColorTarget) -> bool {
+    match target {
+        ColorTarget::Red => r >= 200 && g <= 60 && b <= 60,
+        ColorTarget::Blue => r <= 60 && g <= 60 && b >= 200,
+    }
+}