Gate all use of tracing behind Cargo feature (#33845)

Signed-off-by: Delan Azabani <dazabani@igalia.com>

components/compositing/Cargo.toml

@@ -14,6 +14,7 @@ path = "lib.rs"
 [features]
 default = []
 multiview = []
+tracing = ["dep:tracing"]
 
 [dependencies]
 base = { workspace = true }
@@ -41,7 +42,7 @@ servo-media = { workspace = true }
 servo_geometry = { path = "../geometry" }
 servo_url = { path = "../url" }
 style_traits = { workspace = true }
-tracing = { workspace = true }
+tracing = { workspace = true, optional = true }
 webrender = { workspace = true }
 webrender_api = { workspace = true }
 webrender_traits = { workspace = true }

components/compositing/compositor.rs

@@ -35,7 +35,6 @@ use script_traits::{
 };
 use servo_geometry::{DeviceIndependentPixel, FramebufferUintLength};
 use style_traits::{CSSPixel, DevicePixel, PinchZoomFactor};
-use tracing::{instrument, span, Level};
 use webrender::{CaptureBits, RenderApi, Transaction};
 use webrender_api::units::{
     DeviceIntPoint, DeviceIntSize, DevicePoint, DeviceRect, LayoutPoint, LayoutRect, LayoutSize,
@@ -661,7 +660,10 @@ impl<Window: WindowMethods + ?Sized> IOCompositor<Window> {
 
     /// Accept messages from content processes that need to be relayed to the WebRender
     /// instance in the parent process.
-    #[instrument(skip_all, fields(servo_profiling = true))]
+    #[cfg_attr(
+        feature = "tracing",
+        tracing::instrument(skip_all, fields(servo_profiling = true))
+    )]
     fn handle_cross_process_message(&mut self, msg: CrossProcessCompositorMessage) {
         match msg {
             CrossProcessCompositorMessage::SendInitialTransaction(pipeline) => {
@@ -747,11 +749,13 @@ impl<Window: WindowMethods + ?Sized> IOCompositor<Window> {
                     display_list_descriptor,
                 );
 
-                let span = span!(
+                #[cfg(feature = "tracing")]
-                    Level::TRACE,
+                let span = tracing::span!(
+                    tracing::Level::TRACE,
                     "ScriptToCompositorMsg::BuiltDisplayList",
                     servo_profiling = true
                 );
+                #[cfg(feature = "tracing")]
                 let _enter = span.enter();
                 let pipeline_id = display_list_info.pipeline_id;
                 let details = self.pipeline_details(pipeline_id.into());
@@ -2006,7 +2010,10 @@ impl<Window: WindowMethods + ?Sized> IOCompositor<Window> {
     /// Returns Ok if composition was performed or Err if it was not possible to composite for some
     /// reason. When the target is [CompositeTarget::SharedMemory], the image is read back from the
     /// GPU and returned as Ok(Some(png::Image)), otherwise we return Ok(None).
-    #[instrument(skip_all, fields(servo_profiling = true))]
+    #[cfg_attr(
+        feature = "tracing",
+        tracing::instrument(skip_all, fields(servo_profiling = true))
+    )]
     fn composite_specific_target(
         &mut self,
         target: CompositeTarget,
@@ -2219,11 +2226,13 @@ impl<Window: WindowMethods + ?Sized> IOCompositor<Window> {
             },
         };
 
-        let span = span!(
+        #[cfg(feature = "tracing")]
-            Level::TRACE,
+        let span = tracing::span!(
+            tracing::Level::TRACE,
             "ConstellationMsg::ReadyToPresent",
             servo_profiling = true
         );
+        #[cfg(feature = "tracing")]
         let _enter = span.enter();
         // Notify embedder that servo is ready to present.
         // Embedder should call `present` to tell compositor to continue rendering.
@@ -2249,13 +2258,18 @@ impl<Window: WindowMethods + ?Sized> IOCompositor<Window> {
             .map(|info| info.framebuffer_id())
     }
 
-    #[instrument(skip_all, fields(servo_profiling = true))]
+    #[cfg_attr(
+        feature = "tracing",
+        tracing::instrument(skip_all, fields(servo_profiling = true))
+    )]
     pub fn present(&mut self) {
-        let span = span!(
+        #[cfg(feature = "tracing")]
-            Level::TRACE,
+        let span = tracing::span!(
+            tracing::Level::TRACE,
             "Compositor Present Surface",
             servo_profiling = true
         );
+        #[cfg(feature = "tracing")]
         let _enter = span.enter();
         if let Err(err) = self.rendering_context.present() {
             warn!("Failed to present surface: {:?}", err);
@@ -2318,7 +2332,10 @@ impl<Window: WindowMethods + ?Sized> IOCompositor<Window> {
         );
     }
 
-    #[instrument(skip_all, fields(servo_profiling = true))]
+    #[cfg_attr(
+        feature = "tracing",
+        tracing::instrument(skip_all, fields(servo_profiling = true))
+    )]
     pub fn receive_messages(&mut self) -> bool {
         // Check for new messages coming from the other threads in the system.
         let mut compositor_messages = vec![];
@@ -2345,7 +2362,10 @@ impl<Window: WindowMethods + ?Sized> IOCompositor<Window> {
         true
     }
 
-    #[instrument(skip_all, fields(servo_profiling = true))]
+    #[cfg_attr(
+        feature = "tracing",
+        tracing::instrument(skip_all, fields(servo_profiling = true))
+    )]
     pub fn perform_updates(&mut self) -> bool {
         if self.shutdown_state == ShutdownState::FinishedShuttingDown {
             return false;

components/constellation/Cargo.toml

@@ -14,6 +14,7 @@ path = "lib.rs"
 [features]
 default = []
 multiview = []
+tracing = ["dep:tracing"]
 
 [dependencies]
 background_hang_monitor_api = { workspace = true }
@@ -45,11 +46,11 @@ servo_config = { path = "../config" }
 servo_rand = { path = "../rand" }
 servo_url = { path = "../url" }
 style_traits = { workspace = true }
+tracing = { workspace = true, optional = true }
 webgpu = { path = "../webgpu" }
 webrender = { workspace = true }
 webrender_api = { workspace = true }
 webrender_traits = { workspace = true }
-tracing = { workspace = true }
 webxr-api = { git = "https://github.com/servo/webxr", features = ["ipc"] }
 
 [target.'cfg(any(target_os="macos", all(not(target_os = "windows"), not(target_os = "ios"), not(target_os="android"), not(target_arch="arm"), not(target_arch="aarch64"))))'.dependencies]

components/constellation/constellation.rs

@@ -151,7 +151,6 @@ use servo_config::{opts, pref};
 use servo_rand::{random, Rng, ServoRng, SliceRandom};
 use servo_url::{Host, ImmutableOrigin, ServoUrl};
 use style_traits::CSSPixel;
-use tracing::{instrument, span, Level};
 use webgpu::swapchain::WGPUImageMap;
 use webgpu::{self, WebGPU, WebGPURequest, WebGPUResponse};
 use webrender::{RenderApi, RenderApiSender};
@@ -609,7 +608,10 @@ where
 {
     /// Create a new constellation thread.
     #[allow(clippy::too_many_arguments)]
-    #[tracing::instrument(skip(state, layout_factory), fields(servo_profiling = true))]
+    #[cfg_attr(
+        feature = "tracing",
+        tracing::instrument(skip(state, layout_factory), fields(servo_profiling = true))
+    )]
     pub fn start(
         state: InitialConstellationState,
         layout_factory: Arc<dyn LayoutFactory>,
@@ -1153,7 +1155,10 @@ where
     }
 
     /// Handles loading pages, navigation, and granting access to the compositor
-    #[instrument(skip_all, fields(servo_profiling = true))]
+    #[cfg_attr(
+        feature = "tracing",
+        tracing::instrument(skip_all, fields(servo_profiling = true))
+    )]
     fn handle_request(&mut self) {
         #[derive(Debug)]
         enum Request {
@@ -1250,13 +1255,19 @@ where
         }
     }
 
-    #[instrument(skip_all, fields(servo_profiling = true))]
+    #[cfg_attr(
+        feature = "tracing",
+        tracing::instrument(skip_all, fields(servo_profiling = true))
+    )]
     fn handle_request_for_pipeline_namespace(&mut self, request: PipelineNamespaceRequest) {
         let PipelineNamespaceRequest(sender) = request;
         let _ = sender.send(self.next_pipeline_namespace_id());
     }
 
-    #[instrument(skip_all, fields(servo_profiling = true))]
+    #[cfg_attr(
+        feature = "tracing",
+        tracing::instrument(skip_all, fields(servo_profiling = true))
+    )]
     fn handle_request_from_background_hang_monitor(&self, message: HangMonitorAlert) {
         match message {
             HangMonitorAlert::Profile(bytes) => self
@@ -1270,7 +1281,10 @@ where
         }
     }
 
-    #[instrument(skip_all, fields(servo_profiling = true))]
+    #[cfg_attr(
+        feature = "tracing",
+        tracing::instrument(skip_all, fields(servo_profiling = true))
+    )]
     fn handle_request_from_network_listener(&mut self, message: (PipelineId, FetchResponseMsg)) {
         let (id, message_) = message;
         let result = match self.pipelines.get(&id) {
@@ -1296,7 +1310,10 @@ where
         }
     }
 
-    #[instrument(skip_all, fields(servo_profiling = true))]
+    #[cfg_attr(
+        feature = "tracing",
+        tracing::instrument(skip_all, fields(servo_profiling = true))
+    )]
     fn handle_request_from_compositor(&mut self, message: FromCompositorMsg) {
         trace_msg_from_compositor!(message, "{message:?}");
         match message {
@@ -1509,11 +1526,13 @@ where
                 self.set_webview_throttled(webview_id, throttled);
             },
             FromCompositorMsg::ReadyToPresent(webview_ids) => {
-                let span = span!(
+                #[cfg(feature = "tracing")]
-                    Level::TRACE,
+                let span = tracing::span!(
+                    tracing::Level::TRACE,
                     "FromCompositorMsg::ReadyToPresent",
                     servo_profiling = true
                 );
+                #[cfg(feature = "tracing")]
                 let _enter = span.enter();
                 self.embedder_proxy
                     .send((None, EmbedderMsg::ReadyToPresent(webview_ids)));
@@ -1524,7 +1543,10 @@ where
         }
     }
 
-    #[instrument(skip_all, fields(servo_profiling = true))]
+    #[cfg_attr(
+        feature = "tracing",
+        tracing::instrument(skip_all, fields(servo_profiling = true))
+    )]
     fn handle_request_from_script(&mut self, message: (PipelineId, FromScriptMsg)) {
         let (source_pipeline_id, content) = message;
         trace_script_msg!(content, "{source_pipeline_id}: {content:?}");
@@ -1842,7 +1864,10 @@ where
     }
 
     /// Broadcast a message via routers in various event-loops.
-    #[instrument(skip_all, fields(servo_profiling = true))]
+    #[cfg_attr(
+        feature = "tracing",
+        tracing::instrument(skip_all, fields(servo_profiling = true))
+    )]
     fn handle_schedule_broadcast(
         &self,
         pipeline_id: PipelineId,
@@ -1886,7 +1911,10 @@ where
     }
 
     /// Remove a channel-name for a given broadcast router.
-    #[instrument(skip_all, fields(servo_profiling = true))]
+    #[cfg_attr(
+        feature = "tracing",
+        tracing::instrument(skip_all, fields(servo_profiling = true))
+    )]
     fn handle_remove_broadcast_channel_name_in_router(
         &mut self,
         pipeline_id: PipelineId,
@@ -1922,7 +1950,10 @@ where
     }
 
     /// Note a new channel-name relevant to a given broadcast router.
-    #[instrument(skip_all, fields(servo_profiling = true))]
+    #[cfg_attr(
+        feature = "tracing",
+        tracing::instrument(skip_all, fields(servo_profiling = true))
+    )]
     fn handle_new_broadcast_channel_name_in_router(
         &mut self,
         pipeline_id: PipelineId,
@@ -1944,7 +1975,10 @@ where
     }
 
     /// Remove a broadcast router.
-    #[instrument(skip_all, fields(servo_profiling = true))]
+    #[cfg_attr(
+        feature = "tracing",
+        tracing::instrument(skip_all, fields(servo_profiling = true))
+    )]
     fn handle_remove_broadcast_channel_router(
         &mut self,
         pipeline_id: PipelineId,
@@ -1963,7 +1997,10 @@ where
     }
 
     /// Add a new broadcast router.
-    #[instrument(skip_all, fields(servo_profiling = true))]
+    #[cfg_attr(
+        feature = "tracing",
+        tracing::instrument(skip_all, fields(servo_profiling = true))
+    )]
     fn handle_new_broadcast_channel_router(
         &mut self,
         pipeline_id: PipelineId,
@@ -1986,7 +2023,10 @@ where
         }
     }
 
-    #[instrument(skip_all, fields(servo_profiling = true))]
+    #[cfg_attr(
+        feature = "tracing",
+        tracing::instrument(skip_all, fields(servo_profiling = true))
+    )]
     fn handle_wgpu_request(
         &mut self,
         source_pipeline_id: PipelineId,
@@ -2064,7 +2104,10 @@ where
         }
     }
 
-    #[instrument(skip_all, fields(servo_profiling = true))]
+    #[cfg_attr(
+        feature = "tracing",
+        tracing::instrument(skip_all, fields(servo_profiling = true))
+    )]
     fn handle_request_from_layout(&mut self, message: FromLayoutMsg) {
         trace_layout_msg!(message, "{message:?}");
         match message {
@@ -2079,7 +2122,10 @@ where
         }
     }
 
-    #[instrument(skip_all, fields(servo_profiling = true))]
+    #[cfg_attr(
+        feature = "tracing",
+        tracing::instrument(skip_all, fields(servo_profiling = true))
+    )]
     fn handle_message_port_transfer_completed(
         &mut self,
         router_id: Option<MessagePortRouterId>,
@@ -2218,7 +2264,10 @@ where
         }
     }
 
-    #[instrument(skip_all, fields(servo_profiling = true))]
+    #[cfg_attr(
+        feature = "tracing",
+        tracing::instrument(skip_all, fields(servo_profiling = true))
+    )]
     fn handle_complete_message_port_transfer(
         &mut self,
         router_id: MessagePortRouterId,
@@ -2299,7 +2348,10 @@ where
         }
     }
 
-    #[instrument(skip_all, fields(servo_profiling = true))]
+    #[cfg_attr(
+        feature = "tracing",
+        tracing::instrument(skip_all, fields(servo_profiling = true))
+    )]
     fn handle_reroute_messageport(&mut self, port_id: MessagePortId, task: PortMessageTask) {
         let info = match self.message_ports.get_mut(&port_id) {
             Some(info) => info,
@@ -2331,7 +2383,10 @@ where
         }
     }
 
-    #[instrument(skip_all, fields(servo_profiling = true))]
+    #[cfg_attr(
+        feature = "tracing",
+        tracing::instrument(skip_all, fields(servo_profiling = true))
+    )]
     fn handle_messageport_shipped(&mut self, port_id: MessagePortId) {
         if let Some(info) = self.message_ports.get_mut(&port_id) {
             match info.state {
@@ -2386,7 +2441,10 @@ where
         }
     }
 
-    #[instrument(skip_all, fields(servo_profiling = true))]
+    #[cfg_attr(
+        feature = "tracing",
+        tracing::instrument(skip_all, fields(servo_profiling = true))
+    )]
     fn handle_remove_messageport(&mut self, port_id: MessagePortId) {
         let entangled = match self.message_ports.remove(&port_id) {
             Some(info) => info.entangled_with,
@@ -2434,7 +2492,10 @@ where
         }
     }
 
-    #[instrument(skip_all, fields(servo_profiling = true))]
+    #[cfg_attr(
+        feature = "tracing",
+        tracing::instrument(skip_all, fields(servo_profiling = true))
+    )]
     fn handle_entangle_messageports(&mut self, port1: MessagePortId, port2: MessagePortId) {
         if let Some(info) = self.message_ports.get_mut(&port1) {
             info.entangled_with = Some(port2);
@@ -2460,7 +2521,10 @@ where
     ///
     /// The Job Queue is essentially the channel to a SW manager,
     /// which are scoped per origin.
-    #[instrument(skip_all, fields(servo_profiling = true))]
+    #[cfg_attr(
+        feature = "tracing",
+        tracing::instrument(skip_all, fields(servo_profiling = true))
+    )]
     fn handle_schedule_serviceworker_job(&mut self, pipeline_id: PipelineId, job: Job) {
         let origin = job.scope_url.origin();
 
@@ -2500,7 +2564,10 @@ where
         let _ = sw_manager.send(ServiceWorkerMsg::ScheduleJob(job));
     }
 
-    #[instrument(skip_all, fields(servo_profiling = true))]
+    #[cfg_attr(
+        feature = "tracing",
+        tracing::instrument(skip_all, fields(servo_profiling = true))
+    )]
     fn handle_broadcast_storage_event(
         &self,
         pipeline_id: PipelineId,
@@ -2531,7 +2598,10 @@ where
         }
     }
 
-    #[instrument(skip_all, fields(servo_profiling = true))]
+    #[cfg_attr(
+        feature = "tracing",
+        tracing::instrument(skip_all, fields(servo_profiling = true))
+    )]
     fn handle_exit(&mut self) {
         debug!("Handling exit.");
 
@@ -2612,7 +2682,10 @@ where
         }
     }
 
-    #[instrument(skip_all, fields(servo_profiling = true))]
+    #[cfg_attr(
+        feature = "tracing",
+        tracing::instrument(skip_all, fields(servo_profiling = true))
+    )]
     fn handle_shutdown(&mut self) {
         debug!("Handling shutdown.");
 
@@ -2737,7 +2810,10 @@ where
         self.pipelines.remove(&pipeline_id);
     }
 
-    #[instrument(skip_all, fields(servo_profiling = true))]
+    #[cfg_attr(
+        feature = "tracing",
+        tracing::instrument(skip_all, fields(servo_profiling = true))
+    )]
     fn handle_send_error(&mut self, pipeline_id: PipelineId, err: IpcError) {
         // Treat send error the same as receiving a panic message
         error!("{}: Send error ({})", pipeline_id, err);
@@ -2749,7 +2825,10 @@ where
         self.handle_panic(top_level_browsing_context_id, reason, None);
     }
 
-    #[instrument(skip_all, fields(servo_profiling = true))]
+    #[cfg_attr(
+        feature = "tracing",
+        tracing::instrument(skip_all, fields(servo_profiling = true))
+    )]
     fn handle_panic(
         &mut self,
         top_level_browsing_context_id: Option<TopLevelBrowsingContextId>,
@@ -2847,7 +2926,10 @@ where
         });
     }
 
-    #[instrument(skip_all, fields(servo_profiling = true))]
+    #[cfg_attr(
+        feature = "tracing",
+        tracing::instrument(skip_all, fields(servo_profiling = true))
+    )]
     fn handle_log_entry(
         &mut self,
         top_level_browsing_context_id: Option<TopLevelBrowsingContextId>,
@@ -2927,7 +3009,10 @@ where
         }
     }
 
-    #[instrument(skip_all, fields(servo_profiling = true))]
+    #[cfg_attr(
+        feature = "tracing",
+        tracing::instrument(skip_all, fields(servo_profiling = true))
+    )]
     fn handle_new_top_level_browsing_context(
         &mut self,
         url: ServoUrl,
@@ -2994,7 +3079,10 @@ where
         });
     }
 
-    #[instrument(skip_all, fields(servo_profiling = true))]
+    #[cfg_attr(
+        feature = "tracing",
+        tracing::instrument(skip_all, fields(servo_profiling = true))
+    )]
     fn handle_close_top_level_browsing_context(
         &mut self,
         top_level_browsing_context_id: TopLevelBrowsingContextId,
@@ -3041,7 +3129,10 @@ where
         debug!("{top_level_browsing_context_id}: Closed");
     }
 
-    #[instrument(skip_all, fields(servo_profiling = true))]
+    #[cfg_attr(
+        feature = "tracing",
+        tracing::instrument(skip_all, fields(servo_profiling = true))
+    )]
     fn handle_iframe_size_msg(&mut self, iframe_sizes: Vec<IFrameSizeMsg>) {
         for IFrameSizeMsg {
             browsing_context_id,
@@ -3058,7 +3149,10 @@ where
         }
     }
 
-    #[instrument(skip_all, fields(servo_profiling = true))]
+    #[cfg_attr(
+        feature = "tracing",
+        tracing::instrument(skip_all, fields(servo_profiling = true))
+    )]
     fn handle_subframe_loaded(&mut self, pipeline_id: PipelineId) {
         let browsing_context_id = match self.pipelines.get(&pipeline_id) {
             Some(pipeline) => pipeline.browsing_context_id,
@@ -3099,7 +3193,10 @@ where
         }
     }
 
-    #[instrument(skip_all, fields(servo_profiling = true))]
+    #[cfg_attr(
+        feature = "tracing",
+        tracing::instrument(skip_all, fields(servo_profiling = true))
+    )]
     fn handle_navigate_request(
         &self,
         id: PipelineId,
@@ -3120,7 +3217,10 @@ where
     // iframe via script. This will result in a new pipeline being spawned and
     // a child being added to the parent browsing context. This message is never
     // the result of a page navigation.
-    #[instrument(skip_all, fields(servo_profiling = true))]
+    #[cfg_attr(
+        feature = "tracing",
+        tracing::instrument(skip_all, fields(servo_profiling = true))
+    )]
     fn handle_script_loaded_url_in_iframe_msg(&mut self, load_info: IFrameLoadInfoWithData) {
         let IFrameLoadInfo {
             parent_pipeline_id,
@@ -3227,7 +3327,10 @@ where
         });
     }
 
-    #[instrument(skip_all, fields(servo_profiling = true))]
+    #[cfg_attr(
+        feature = "tracing",
+        tracing::instrument(skip_all, fields(servo_profiling = true))
+    )]
     fn handle_script_new_iframe(&mut self, load_info: IFrameLoadInfoWithData) {
         let IFrameLoadInfo {
             parent_pipeline_id,
@@ -3288,7 +3391,10 @@ where
         });
     }
 
-    #[instrument(skip_all, fields(servo_profiling = true))]
+    #[cfg_attr(
+        feature = "tracing",
+        tracing::instrument(skip_all, fields(servo_profiling = true))
+    )]
     fn handle_script_new_auxiliary(&mut self, load_info: AuxiliaryBrowsingContextLoadInfo) {
         let AuxiliaryBrowsingContextLoadInfo {
             load_data,
@@ -3374,19 +3480,28 @@ where
         });
     }
 
-    #[instrument(skip_all, fields(servo_profiling = true))]
+    #[cfg_attr(
+        feature = "tracing",
+        tracing::instrument(skip_all, fields(servo_profiling = true))
+    )]
     fn handle_pending_paint_metric(&self, pipeline_id: PipelineId, epoch: Epoch) {
         self.compositor_proxy
             .send(CompositorMsg::PendingPaintMetric(pipeline_id, epoch))
     }
 
-    #[instrument(skip_all, fields(servo_profiling = true))]
+    #[cfg_attr(
+        feature = "tracing",
+        tracing::instrument(skip_all, fields(servo_profiling = true))
+    )]
     fn handle_set_cursor_msg(&mut self, cursor: Cursor) {
         self.embedder_proxy
             .send((None, EmbedderMsg::SetCursor(cursor)))
     }
 
-    #[instrument(skip_all, fields(servo_profiling = true))]
+    #[cfg_attr(
+        feature = "tracing",
+        tracing::instrument(skip_all, fields(servo_profiling = true))
+    )]
     fn handle_change_running_animations_state(
         &mut self,
         pipeline_id: PipelineId,
@@ -3404,7 +3519,10 @@ where
         }
     }
 
-    #[instrument(skip_all, fields(servo_profiling = true))]
+    #[cfg_attr(
+        feature = "tracing",
+        tracing::instrument(skip_all, fields(servo_profiling = true))
+    )]
     fn handle_tick_animation(&mut self, pipeline_id: PipelineId, tick_type: AnimationTickType) {
         let pipeline = match self.pipelines.get(&pipeline_id) {
             Some(pipeline) => pipeline,
@@ -3420,7 +3538,10 @@ where
     /// Schedule a navigation(via load_url).
     /// 1: Ask the embedder for permission.
     /// 2: Store the details of the navigation, pending approval from the embedder.
-    #[instrument(skip_all, fields(servo_profiling = true))]
+    #[cfg_attr(
+        feature = "tracing",
+        tracing::instrument(skip_all, fields(servo_profiling = true))
+    )]
     fn schedule_navigation(
         &mut self,
         top_level_browsing_context_id: TopLevelBrowsingContextId,
@@ -3447,7 +3568,10 @@ where
         self.embedder_proxy.send(msg);
     }
 
-    #[instrument(skip_all, fields(servo_profiling = true))]
+    #[cfg_attr(
+        feature = "tracing",
+        tracing::instrument(skip_all, fields(servo_profiling = true))
+    )]
     fn load_url(
         &mut self,
         top_level_browsing_context_id: TopLevelBrowsingContextId,
@@ -3576,7 +3700,10 @@ where
         }
     }
 
-    #[instrument(skip_all, fields(servo_profiling = true))]
+    #[cfg_attr(
+        feature = "tracing",
+        tracing::instrument(skip_all, fields(servo_profiling = true))
+    )]
     fn handle_abort_load_url_msg(&mut self, new_pipeline_id: PipelineId) {
         let pending_index = self
             .pending_changes
@@ -3594,7 +3721,10 @@ where
         }
     }
 
-    #[instrument(skip_all, fields(servo_profiling = true))]
+    #[cfg_attr(
+        feature = "tracing",
+        tracing::instrument(skip_all, fields(servo_profiling = true))
+    )]
     fn handle_load_complete_msg(
         &mut self,
         top_level_browsing_context_id: TopLevelBrowsingContextId,
@@ -3643,7 +3773,10 @@ where
         }
     }
 
-    #[instrument(skip_all, fields(servo_profiling = true))]
+    #[cfg_attr(
+        feature = "tracing",
+        tracing::instrument(skip_all, fields(servo_profiling = true))
+    )]
     fn handle_navigated_to_fragment(
         &mut self,
         pipeline_id: PipelineId,
@@ -3675,7 +3808,10 @@ where
         }
     }
 
-    #[instrument(skip_all, fields(servo_profiling = true))]
+    #[cfg_attr(
+        feature = "tracing",
+        tracing::instrument(skip_all, fields(servo_profiling = true))
+    )]
     fn handle_traverse_history_msg(
         &mut self,
         top_level_browsing_context_id: TopLevelBrowsingContextId,
@@ -3817,7 +3953,10 @@ where
         self.update_webview_in_compositor(top_level_browsing_context_id);
     }
 
-    #[instrument(skip_all, fields(servo_profiling = true))]
+    #[cfg_attr(
+        feature = "tracing",
+        tracing::instrument(skip_all, fields(servo_profiling = true))
+    )]
     fn update_browsing_context(
         &mut self,
         browsing_context_id: BrowsingContextId,
@@ -3942,7 +4081,10 @@ where
         }
     }
 
-    #[instrument(skip_all, fields(servo_profiling = true))]
+    #[cfg_attr(
+        feature = "tracing",
+        tracing::instrument(skip_all, fields(servo_profiling = true))
+    )]
     fn update_pipeline(
         &mut self,
         pipeline_id: PipelineId,
@@ -3969,7 +4111,10 @@ where
         }
     }
 
-    #[instrument(skip_all, fields(servo_profiling = true))]
+    #[cfg_attr(
+        feature = "tracing",
+        tracing::instrument(skip_all, fields(servo_profiling = true))
+    )]
     fn handle_joint_session_history_length(
         &self,
         top_level_browsing_context_id: TopLevelBrowsingContextId,
@@ -3983,7 +4128,10 @@ where
         let _ = response_sender.send(length as u32);
     }
 
-    #[instrument(skip_all, fields(servo_profiling = true))]
+    #[cfg_attr(
+        feature = "tracing",
+        tracing::instrument(skip_all, fields(servo_profiling = true))
+    )]
     fn handle_push_history_state_msg(
         &mut self,
         pipeline_id: PipelineId,
@@ -4023,7 +4171,10 @@ where
         self.notify_history_changed(top_level_browsing_context_id);
     }
 
-    #[instrument(skip_all, fields(servo_profiling = true))]
+    #[cfg_attr(
+        feature = "tracing",
+        tracing::instrument(skip_all, fields(servo_profiling = true))
+    )]
     fn handle_replace_history_state_msg(
         &mut self,
         pipeline_id: PipelineId,
@@ -4048,7 +4199,10 @@ where
         session_history.replace_history_state(pipeline_id, history_state_id, url);
     }
 
-    #[instrument(skip_all, fields(servo_profiling = true))]
+    #[cfg_attr(
+        feature = "tracing",
+        tracing::instrument(skip_all, fields(servo_profiling = true))
+    )]
     fn handle_ime_dismissed(&mut self) {
         // Send to the focused browsing contexts' current pipeline.
         let focused_browsing_context_id = self
@@ -4079,7 +4233,10 @@ where
         }
     }
 
-    #[instrument(skip_all, fields(servo_profiling = true))]
+    #[cfg_attr(
+        feature = "tracing",
+        tracing::instrument(skip_all, fields(servo_profiling = true))
+    )]
     fn handle_key_msg(&mut self, event: KeyboardEvent) {
         // Send to the focused browsing contexts' current pipeline.  If it
         // doesn't exist, fall back to sending to the compositor.
@@ -4118,7 +4275,10 @@ where
         }
     }
 
-    #[instrument(skip_all, fields(servo_profiling = true))]
+    #[cfg_attr(
+        feature = "tracing",
+        tracing::instrument(skip_all, fields(servo_profiling = true))
+    )]
     fn handle_reload_msg(&mut self, top_level_browsing_context_id: TopLevelBrowsingContextId) {
         let browsing_context_id = BrowsingContextId::from(top_level_browsing_context_id);
         let pipeline_id = match self.browsing_contexts.get(&browsing_context_id) {
@@ -4137,7 +4297,10 @@ where
         }
     }
 
-    #[instrument(skip_all, fields(servo_profiling = true))]
+    #[cfg_attr(
+        feature = "tracing",
+        tracing::instrument(skip_all, fields(servo_profiling = true))
+    )]
     fn handle_post_message_msg(
         &mut self,
         browsing_context_id: BrowsingContextId,
@@ -4176,7 +4339,10 @@ where
         }
     }
 
-    #[instrument(skip_all, fields(servo_profiling = true))]
+    #[cfg_attr(
+        feature = "tracing",
+        tracing::instrument(skip_all, fields(servo_profiling = true))
+    )]
     fn handle_get_pipeline(
         &mut self,
         browsing_context_id: BrowsingContextId,
@@ -4198,7 +4364,10 @@ where
         }
     }
 
-    #[instrument(skip_all, fields(servo_profiling = true))]
+    #[cfg_attr(
+        feature = "tracing",
+        tracing::instrument(skip_all, fields(servo_profiling = true))
+    )]
     fn handle_get_browsing_context(
         &mut self,
         pipeline_id: PipelineId,
@@ -4213,7 +4382,10 @@ where
         }
     }
 
-    #[instrument(skip_all, fields(servo_profiling = true))]
+    #[cfg_attr(
+        feature = "tracing",
+        tracing::instrument(skip_all, fields(servo_profiling = true))
+    )]
     fn handle_focus_msg(&mut self, pipeline_id: PipelineId) {
         let (browsing_context_id, top_level_browsing_context_id) =
             match self.pipelines.get(&pipeline_id) {
@@ -4248,7 +4420,10 @@ where
         self.focus_parent_pipeline(browsing_context_id);
     }
 
-    #[instrument(skip_all, fields(servo_profiling = true))]
+    #[cfg_attr(
+        feature = "tracing",
+        tracing::instrument(skip_all, fields(servo_profiling = true))
+    )]
     fn focus_parent_pipeline(&mut self, browsing_context_id: BrowsingContextId) {
         let parent_pipeline_id = match self.browsing_contexts.get(&browsing_context_id) {
             Some(ctx) => ctx.parent_pipeline_id,
@@ -4279,7 +4454,10 @@ where
         self.focus_parent_pipeline(parent_browsing_context_id);
     }
 
-    #[instrument(skip_all, fields(servo_profiling = true))]
+    #[cfg_attr(
+        feature = "tracing",
+        tracing::instrument(skip_all, fields(servo_profiling = true))
+    )]
     fn handle_remove_iframe_msg(
         &mut self,
         browsing_context_id: BrowsingContextId,
@@ -4292,7 +4470,10 @@ where
         result
     }
 
-    #[instrument(skip_all, fields(servo_profiling = true))]
+    #[cfg_attr(
+        feature = "tracing",
+        tracing::instrument(skip_all, fields(servo_profiling = true))
+    )]
     fn handle_set_throttled_complete(&mut self, pipeline_id: PipelineId, throttled: bool) {
         let browsing_context_id = match self.pipelines.get(&pipeline_id) {
             Some(pipeline) => pipeline.browsing_context_id,
@@ -4327,7 +4508,10 @@ where
         }
     }
 
-    #[instrument(skip_all, fields(servo_profiling = true))]
+    #[cfg_attr(
+        feature = "tracing",
+        tracing::instrument(skip_all, fields(servo_profiling = true))
+    )]
     fn handle_create_canvas_paint_thread_msg(
         &mut self,
         size: UntypedSize2D<u64>,
@@ -4351,7 +4535,10 @@ where
         }
     }
 
-    #[instrument(skip_all, fields(servo_profiling = true))]
+    #[cfg_attr(
+        feature = "tracing",
+        tracing::instrument(skip_all, fields(servo_profiling = true))
+    )]
     fn handle_webdriver_msg(&mut self, msg: WebDriverCommandMsg) {
         // Find the script channel for the given parent pipeline,
         // and pass the event to that script thread.
@@ -4482,7 +4669,10 @@ where
         }
     }
 
-    #[instrument(skip_all, fields(servo_profiling = true))]
+    #[cfg_attr(
+        feature = "tracing",
+        tracing::instrument(skip_all, fields(servo_profiling = true))
+    )]
     fn set_webview_throttled(&mut self, webview_id: WebViewId, throttled: bool) {
         let browsing_context_id = BrowsingContextId::from(webview_id);
         let pipeline_id = match self.browsing_contexts.get(&browsing_context_id) {
@@ -4497,7 +4687,10 @@ where
         }
     }
 
-    #[instrument(skip_all, fields(servo_profiling = true))]
+    #[cfg_attr(
+        feature = "tracing",
+        tracing::instrument(skip_all, fields(servo_profiling = true))
+    )]
     fn notify_history_changed(&self, top_level_browsing_context_id: TopLevelBrowsingContextId) {
         // Send a flat projection of the history to embedder.
         // The final vector is a concatenation of the LoadData of the past
@@ -4614,7 +4807,10 @@ where
         self.embedder_proxy.send(msg);
     }
 
-    #[instrument(skip_all, fields(servo_profiling = true))]
+    #[cfg_attr(
+        feature = "tracing",
+        tracing::instrument(skip_all, fields(servo_profiling = true))
+    )]
     fn load_url_for_webdriver(
         &mut self,
         top_level_browsing_context_id: TopLevelBrowsingContextId,
@@ -4642,7 +4838,10 @@ where
         }
     }
 
-    #[instrument(skip_all, fields(servo_profiling = true))]
+    #[cfg_attr(
+        feature = "tracing",
+        tracing::instrument(skip_all, fields(servo_profiling = true))
+    )]
     fn change_session_history(&mut self, change: SessionHistoryChange) {
         debug!(
             "{}: Setting to {}",
@@ -4797,7 +4996,10 @@ where
         self.update_webview_in_compositor(change.top_level_browsing_context_id);
     }
 
-    #[instrument(skip_all, fields(servo_profiling = true))]
+    #[cfg_attr(
+        feature = "tracing",
+        tracing::instrument(skip_all, fields(servo_profiling = true))
+    )]
     fn focused_browsing_context_is_descendant_of(
         &self,
         browsing_context_id: BrowsingContextId,
@@ -4813,7 +5015,10 @@ where
         })
     }
 
-    #[instrument(skip_all, fields(servo_profiling = true))]
+    #[cfg_attr(
+        feature = "tracing",
+        tracing::instrument(skip_all, fields(servo_profiling = true))
+    )]
     fn trim_history(&mut self, top_level_browsing_context_id: TopLevelBrowsingContextId) {
         let pipelines_to_evict = {
             let session_history = self.get_joint_session_history(top_level_browsing_context_id);
@@ -4873,7 +5078,10 @@ where
         }
     }
 
-    #[instrument(skip_all, fields(servo_profiling = true))]
+    #[cfg_attr(
+        feature = "tracing",
+        tracing::instrument(skip_all, fields(servo_profiling = true))
+    )]
     fn handle_activate_document_msg(&mut self, pipeline_id: PipelineId) {
         debug!("{}: Document ready to activate", pipeline_id);
 
@@ -4919,7 +5127,10 @@ where
     }
 
     /// Called when the window is resized.
-    #[instrument(skip_all, fields(servo_profiling = true))]
+    #[cfg_attr(
+        feature = "tracing",
+        tracing::instrument(skip_all, fields(servo_profiling = true))
+    )]
     fn handle_window_size_msg(
         &mut self,
         top_level_browsing_context_id: TopLevelBrowsingContextId,
@@ -4942,7 +5153,10 @@ where
     }
 
     /// Called when the window exits from fullscreen mode
-    #[instrument(skip_all, fields(servo_profiling = true))]
+    #[cfg_attr(
+        feature = "tracing",
+        tracing::instrument(skip_all, fields(servo_profiling = true))
+    )]
     fn handle_exit_fullscreen_msg(
         &mut self,
         top_level_browsing_context_id: TopLevelBrowsingContextId,
@@ -4956,7 +5170,10 @@ where
     /// to check if the output image is "stable" and can be written as a screenshot
     /// for reftests.
     /// Since this function is only used in reftests, we do not harden it against panic.
-    #[instrument(skip_all, fields(servo_profiling = true))]
+    #[cfg_attr(
+        feature = "tracing",
+        tracing::instrument(skip_all, fields(servo_profiling = true))
+    )]
     fn handle_is_ready_to_save_image(
         &mut self,
         pipeline_states: HashMap<PipelineId, Epoch>,
@@ -5040,7 +5257,10 @@ where
     }
 
     /// Get the current activity of a pipeline.
-    #[instrument(skip_all, fields(servo_profiling = true))]
+    #[cfg_attr(
+        feature = "tracing",
+        tracing::instrument(skip_all, fields(servo_profiling = true))
+    )]
     fn get_activity(&self, pipeline_id: PipelineId) -> DocumentActivity {
         let mut ancestor_id = pipeline_id;
         loop {
@@ -5067,7 +5287,10 @@ where
     }
 
     /// Set the current activity of a pipeline.
-    #[instrument(skip_all, fields(servo_profiling = true))]
+    #[cfg_attr(
+        feature = "tracing",
+        tracing::instrument(skip_all, fields(servo_profiling = true))
+    )]
     fn set_activity(&self, pipeline_id: PipelineId, activity: DocumentActivity) {
         debug!("{}: Setting activity to {:?}", pipeline_id, activity);
         if let Some(pipeline) = self.pipelines.get(&pipeline_id) {
@@ -5086,14 +5309,20 @@ where
     }
 
     /// Update the current activity of a pipeline.
-    #[instrument(skip_all, fields(servo_profiling = true))]
+    #[cfg_attr(
+        feature = "tracing",
+        tracing::instrument(skip_all, fields(servo_profiling = true))
+    )]
     fn update_activity(&self, pipeline_id: PipelineId) {
         self.set_activity(pipeline_id, self.get_activity(pipeline_id));
     }
 
     /// Handle updating the size of a browsing context.
     /// This notifies every pipeline in the context of the new size.
-    #[instrument(skip_all, fields(servo_profiling = true))]
+    #[cfg_attr(
+        feature = "tracing",
+        tracing::instrument(skip_all, fields(servo_profiling = true))
+    )]
     fn resize_browsing_context(
         &mut self,
         new_size: WindowSizeData,
@@ -5150,7 +5379,10 @@ where
     }
 
     // Handle switching from fullscreen mode
-    #[instrument(skip_all, fields(servo_profiling = true))]
+    #[cfg_attr(
+        feature = "tracing",
+        tracing::instrument(skip_all, fields(servo_profiling = true))
+    )]
     fn switch_fullscreen_mode(&mut self, browsing_context_id: BrowsingContextId) {
         if let Some(browsing_context) = self.browsing_contexts.get(&browsing_context_id) {
             let pipeline_id = browsing_context.pipeline_id;
@@ -5170,7 +5402,10 @@ where
     }
 
     // Close and return the browsing context with the given id (and its children), if it exists.
-    #[instrument(skip_all, fields(servo_profiling = true))]
+    #[cfg_attr(
+        feature = "tracing",
+        tracing::instrument(skip_all, fields(servo_profiling = true))
+    )]
     fn close_browsing_context(
         &mut self,
         browsing_context_id: BrowsingContextId,
@@ -5210,7 +5445,10 @@ where
     }
 
     // Close the children of a browsing context
-    #[instrument(skip_all, fields(servo_profiling = true))]
+    #[cfg_attr(
+        feature = "tracing",
+        tracing::instrument(skip_all, fields(servo_profiling = true))
+    )]
     fn close_browsing_context_children(
         &mut self,
         browsing_context_id: BrowsingContextId,
@@ -5241,7 +5479,10 @@ where
     }
 
     // Discard the pipeline for a given document, udpdate the joint session history.
-    #[instrument(skip_all, fields(servo_profiling = true))]
+    #[cfg_attr(
+        feature = "tracing",
+        tracing::instrument(skip_all, fields(servo_profiling = true))
+    )]
     fn handle_discard_document(
         &mut self,
         top_level_browsing_context_id: TopLevelBrowsingContextId,
@@ -5273,7 +5514,10 @@ where
     }
 
     // Send a message to script requesting the document associated with this pipeline runs the 'unload' algorithm.
-    #[instrument(skip_all, fields(servo_profiling = true))]
+    #[cfg_attr(
+        feature = "tracing",
+        tracing::instrument(skip_all, fields(servo_profiling = true))
+    )]
     fn unload_document(&self, pipeline_id: PipelineId) {
         if let Some(pipeline) = self.pipelines.get(&pipeline_id) {
             let msg = ConstellationControlMsg::UnloadDocument(pipeline_id);
@@ -5282,7 +5526,10 @@ where
     }
 
     // Close all pipelines at and beneath a given browsing context
-    #[instrument(skip_all, fields(servo_profiling = true))]
+    #[cfg_attr(
+        feature = "tracing",
+        tracing::instrument(skip_all, fields(servo_profiling = true))
+    )]
     fn close_pipeline(
         &mut self,
         pipeline_id: PipelineId,
@@ -5346,7 +5593,10 @@ where
     }
 
     // Randomly close a pipeline -if --random-pipeline-closure-probability is set
-    #[instrument(skip_all, fields(servo_profiling = true))]
+    #[cfg_attr(
+        feature = "tracing",
+        tracing::instrument(skip_all, fields(servo_profiling = true))
+    )]
     fn maybe_close_random_pipeline(&mut self) {
         match self.random_pipeline_closure {
             Some((ref mut rng, probability)) => {
@@ -5384,7 +5634,10 @@ where
         }
     }
 
-    #[instrument(skip_all, fields(servo_profiling = true))]
+    #[cfg_attr(
+        feature = "tracing",
+        tracing::instrument(skip_all, fields(servo_profiling = true))
+    )]
     fn get_joint_session_history(
         &mut self,
         top_level_id: TopLevelBrowsingContextId,
@@ -5396,7 +5649,10 @@ where
     }
 
     // Convert a browsing context to a sendable form to pass to the compositor
-    #[instrument(skip_all, fields(servo_profiling = true))]
+    #[cfg_attr(
+        feature = "tracing",
+        tracing::instrument(skip_all, fields(servo_profiling = true))
+    )]
     fn browsing_context_to_sendable(
         &self,
         browsing_context_id: BrowsingContextId,
@@ -5426,7 +5682,10 @@ where
     }
 
     /// Send the frame tree for the given webview to the compositor.
-    #[instrument(skip_all, fields(servo_profiling = true))]
+    #[cfg_attr(
+        feature = "tracing",
+        tracing::instrument(skip_all, fields(servo_profiling = true))
+    )]
     fn update_webview_in_compositor(&mut self, webview_id: WebViewId) {
         // Note that this function can panic, due to ipc-channel creation failure.
         // avoiding this panic would require a mechanism for dealing
@@ -5439,7 +5698,10 @@ where
         }
     }
 
-    #[instrument(skip_all, fields(servo_profiling = true))]
+    #[cfg_attr(
+        feature = "tracing",
+        tracing::instrument(skip_all, fields(servo_profiling = true))
+    )]
     fn handle_media_session_action_msg(&mut self, action: MediaSessionActionType) {
         if let Some(media_session_pipeline_id) = self.active_media_session {
             let result = match self.pipelines.get(&media_session_pipeline_id) {
@@ -5466,7 +5728,10 @@ where
     }
 
     /// Handle GamepadEvents from the embedder and forward them to the script thread
-    #[instrument(skip_all, fields(servo_profiling = true))]
+    #[cfg_attr(
+        feature = "tracing",
+        tracing::instrument(skip_all, fields(servo_profiling = true))
+    )]
     fn handle_gamepad_msg(&mut self, event: GamepadEvent) {
         // Send to the focused browsing contexts' current pipeline.
         let focused_browsing_context_id = self

components/fonts/Cargo.toml

@@ -13,6 +13,9 @@ path = "lib.rs"
 test = true
 doctest = false
 
+[features]
+tracing = ["dep:tracing"]
+
 [dependencies]
 app_units = { workspace = true }
 atomic_refcell = { workspace = true }
@@ -44,7 +47,7 @@ servo_url = { path = "../url" }
 smallvec = { workspace = true, features = ["union"] }
 surfman = { workspace = true }
 style = { workspace = true }
-tracing = { workspace = true }
+tracing = { workspace = true, optional = true }
 unicode-bidi = { workspace = true, features = ["with_serde"] }
 unicode-properties = { workspace = true }
 unicode-script = { workspace = true }

components/fonts/font_context.rs

@@ -28,7 +28,6 @@ use style::shared_lock::SharedRwLockReadGuard;
 use style::stylesheets::{CssRule, DocumentStyleSheet, FontFaceRule, StylesheetInDocument};
 use style::values::computed::font::{FamilyName, FontFamilyNameSyntax, SingleFontFamily};
 use style::Atom;
-use tracing::instrument;
 use url::Url;
 use webrender_api::{FontInstanceFlags, FontInstanceKey, FontKey};
 use webrender_traits::CrossProcessCompositorApi;
@@ -279,7 +278,10 @@ impl FontContext {
 
     /// Create a `Font` for use in layout calculations, from a `FontTemplateData` returned by the
     /// cache thread and a `FontDescriptor` which contains the styling parameters.
-    #[instrument(skip_all, fields(servo_profiling = true))]
+    #[cfg_attr(
+        feature = "tracing",
+        tracing::instrument(skip_all, fields(servo_profiling = true))
+    )]
     fn create_font(
         &self,
         font_template: FontTemplateRef,

components/fonts/system_font_service.rs

@@ -24,7 +24,6 @@ use style::values::computed::font::{
 };
 use style::values::computed::{FontStretch, FontWeight};
 use style::values::specified::FontStretch as SpecifiedFontStretch;
-use tracing::{instrument, span, Level};
 use webrender_api::{FontInstanceFlags, FontInstanceKey, FontKey};
 use webrender_traits::CrossProcessCompositorApi;
 
@@ -146,16 +145,21 @@ impl SystemFontService {
         SystemFontServiceProxySender(sender)
     }
 
-    #[instrument(skip_all, fields(servo_profiling = true))]
+    #[cfg_attr(
+        feature = "tracing",
+        tracing::instrument(skip_all, fields(servo_profiling = true))
+    )]
     fn run(&mut self) {
         loop {
             let msg = self.port.recv().unwrap();
 
-            let span = span!(
+            #[cfg(feature = "tracing")]
-                Level::TRACE,
+            let span = tracing::span!(
+                tracing::Level::TRACE,
                 "SystemFontServiceMessage",
                 servo_profiling = true
             );
+            #[cfg(feature = "tracing")]
             let _enter = span.enter();
             match msg {
                 SystemFontServiceMessage::GetFontTemplates(
@@ -186,7 +190,10 @@ impl SystemFontService {
         }
     }
 
-    #[instrument(skip_all, fields(servo_profiling = true))]
+    #[cfg_attr(
+        feature = "tracing",
+        tracing::instrument(skip_all, fields(servo_profiling = true))
+    )]
     fn fetch_new_keys(&mut self) {
         if !self.free_font_keys.is_empty() && !self.free_font_instance_keys.is_empty() {
             return;
@@ -203,7 +210,10 @@ impl SystemFontService {
             .append(&mut new_font_instance_keys);
     }
 
-    #[instrument(skip_all, fields(servo_profiling = true))]
+    #[cfg_attr(
+        feature = "tracing",
+        tracing::instrument(skip_all, fields(servo_profiling = true))
+    )]
     fn get_font_templates(
         &mut self,
         font_descriptor: Option<FontDescriptor>,
@@ -216,7 +226,10 @@ impl SystemFontService {
             .collect()
     }
 
-    #[instrument(skip_all, fields(servo_profiling = true))]
+    #[cfg_attr(
+        feature = "tracing",
+        tracing::instrument(skip_all, fields(servo_profiling = true))
+    )]
     fn refresh_local_families(&mut self) {
         self.local_families.clear();
         for_each_available_family(|family_name| {
@@ -227,7 +240,10 @@ impl SystemFontService {
         });
     }
 
-    #[instrument(skip_all, fields(servo_profiling = true))]
+    #[cfg_attr(
+        feature = "tracing",
+        tracing::instrument(skip_all, fields(servo_profiling = true))
+    )]
     fn find_font_templates(
         &mut self,
         descriptor_to_match: Option<&FontDescriptor>,
@@ -251,7 +267,10 @@ impl SystemFontService {
             .unwrap_or_default()
     }
 
-    #[instrument(skip_all, fields(servo_profiling = true))]
+    #[cfg_attr(
+        feature = "tracing",
+        tracing::instrument(skip_all, fields(servo_profiling = true))
+    )]
     fn get_font_instance(
         &mut self,
         identifier: FontIdentifier,

components/layout_2020/Cargo.toml

@@ -13,6 +13,9 @@ path = "lib.rs"
 test = true
 doctest = false
 
+[features]
+tracing = ["dep:tracing"]
+
 [dependencies]
 app_units = { workspace = true }
 atomic_refcell = { workspace = true }
@@ -45,8 +48,8 @@ servo_config = { path = "../config" }
 servo_geometry = { path = "../geometry" }
 servo_url = { path = "../url" }
 style = { workspace = true }
-tracing = { workspace = true }
 style_traits = { workspace = true }
+tracing = { workspace = true, optional = true }
 unicode-bidi = { workspace = true }
 unicode-script = { workspace = true }
 url = { workspace = true }

components/layout_2020/flexbox/layout.rs

@@ -19,7 +19,6 @@ use style::values::generics::flex::GenericFlexBasis as FlexBasis;
 use style::values::generics::length::{GenericLengthPercentageOrAuto, LengthPercentageOrNormal};
 use style::values::specified::align::AlignFlags;
 use style::Zero;
-use tracing::instrument;
 
 use super::geom::{FlexAxis, FlexRelativeRect, FlexRelativeSides, FlexRelativeVec2};
 use super::{FlexContainer, FlexContainerConfig, FlexItemBox, FlexLevelBox};
@@ -340,10 +339,13 @@ struct FlexItemBoxInlineContentSizesInfo {
 }
 
 impl FlexContainer {
-    #[instrument(
+    #[cfg_attr(
+        feature = "tracing",
+        tracing::instrument(
             name = "FlexContainer::inline_content_sizes",
             skip_all,
             fields(servo_profiling = true)
+        )
     )]
     pub fn inline_content_sizes(
         &mut self,
@@ -551,10 +553,13 @@ impl FlexContainer {
     }
 
     /// <https://drafts.csswg.org/css-flexbox/#layout-algorithm>
-    #[instrument(
+    #[cfg_attr(
+        feature = "tracing",
+        tracing::instrument(
             name = "FlexContainer::layout",
             skip_all,
             fields(servo_profiling = true)
+        )
     )]
     pub(crate) fn layout(
         &self,
@@ -2490,10 +2495,13 @@ impl FlexItemBox {
     }
 
     #[allow(clippy::too_many_arguments)]
-    #[instrument(
+    #[cfg_attr(
+        feature = "tracing",
+        tracing::instrument(
             name = "FlexContainer::layout_for_block_content_size",
             skip_all,
             fields(servo_profiling = true)
+        )
     )]
     fn layout_for_block_content_size(
         &mut self,

components/layout_2020/table/layout.rs

@@ -24,7 +24,6 @@ use style::values::computed::{
 use style::values::generics::box_::{GenericVerticalAlign as VerticalAlign, VerticalAlignKeyword};
 use style::values::generics::length::GenericLengthPercentageOrAuto::{Auto, LengthPercentage};
 use style::Zero;
-use tracing::instrument;
 
 use super::{Table, TableCaption, TableSlot, TableSlotCell, TableTrack, TableTrackGroup};
 use crate::context::LayoutContext;
@@ -1634,7 +1633,10 @@ impl<'a> TableLayout<'a> {
 
     /// Lay out the table (grid and captions) of this [`TableLayout`] into fragments. This should
     /// only be be called after calling [`TableLayout.compute_measures`].
-    #[instrument(name = "Table::layout", skip_all, fields(servo_profiling = true))]
+    #[cfg_attr(
+        feature = "tracing",
+        tracing::instrument(name = "Table::layout", skip_all, fields(servo_profiling = true))
+    )]
     fn layout(
         mut self,
         layout_context: &LayoutContext,
@@ -2606,10 +2608,13 @@ impl Table {
         }
     }
 
-    #[instrument(
+    #[cfg_attr(
+        feature = "tracing",
+        tracing::instrument(
             name = "Table::inline_content_sizes",
             skip_all,
             fields(servo_profiling = true)
+        )
     )]
     pub(crate) fn inline_content_sizes(
         &mut self,

components/layout_thread_2020/Cargo.toml

@@ -11,6 +11,9 @@ rust-version.workspace = true
 name = "layout_thread_2020"
 path = "lib.rs"
 
+[features]
+tracing = ["dep:tracing", "layout/tracing"]
+
 [dependencies]
 app_units = { workspace = true }
 base = { workspace = true }
@@ -38,7 +41,7 @@ servo_config = { path = "../config" }
 servo_url = { path = "../url" }
 style = { workspace = true }
 style_traits = { workspace = true }
-tracing = { workspace = true }
+tracing = { workspace = true, optional = true }
 url = { workspace = true }
 webrender_api = { workspace = true }
 webrender_traits = { workspace = true }

components/layout_thread_2020/lib.rs

@@ -88,7 +88,6 @@ use style::values::computed::{CSSPixelLength, FontSize, Length, NonNegativeLengt
 use style::values::specified::font::KeywordInfo;
 use style::{driver, Zero};
 use style_traits::{CSSPixel, DevicePixel, SpeculativePainter};
-use tracing::{instrument, span, Level};
 use url::Url;
 use webrender_api::units::LayoutPixel;
 use webrender_api::{units, ExternalScrollId, HitTestFlags};
@@ -254,7 +253,10 @@ impl Layout for LayoutThread {
         );
     }
 
-    #[instrument(skip_all, fields(servo_profiling = true))]
+    #[cfg_attr(
+        feature = "tracing",
+        tracing::instrument(skip_all, fields(servo_profiling = true))
+    )]
     fn add_stylesheet(
         &mut self,
         stylesheet: ServoArc<Stylesheet>,
@@ -274,7 +276,10 @@ impl Layout for LayoutThread {
         }
     }
 
-    #[instrument(skip_all, fields(servo_profiling = true))]
+    #[cfg_attr(
+        feature = "tracing",
+        tracing::instrument(skip_all, fields(servo_profiling = true))
+    )]
     fn remove_stylesheet(&mut self, stylesheet: ServoArc<Stylesheet>) {
         let guard = stylesheet.shared_lock.read();
         let stylesheet = DocumentStyleSheet(stylesheet.clone());
@@ -283,22 +288,34 @@ impl Layout for LayoutThread {
             .remove_all_web_fonts_from_stylesheet(&stylesheet);
     }
 
-    #[instrument(skip_all, fields(servo_profiling = true))]
+    #[cfg_attr(
+        feature = "tracing",
+        tracing::instrument(skip_all, fields(servo_profiling = true))
+    )]
     fn query_content_box(&self, node: OpaqueNode) -> Option<UntypedRect<Au>> {
         process_content_box_request(node, self.fragment_tree.borrow().clone())
     }
 
-    #[instrument(skip_all, fields(servo_profiling = true))]
+    #[cfg_attr(
+        feature = "tracing",
+        tracing::instrument(skip_all, fields(servo_profiling = true))
+    )]
     fn query_content_boxes(&self, node: OpaqueNode) -> Vec<UntypedRect<Au>> {
         process_content_boxes_request(node, self.fragment_tree.borrow().clone())
     }
 
-    #[instrument(skip_all, fields(servo_profiling = true))]
+    #[cfg_attr(
+        feature = "tracing",
+        tracing::instrument(skip_all, fields(servo_profiling = true))
+    )]
     fn query_client_rect(&self, node: OpaqueNode) -> UntypedRect<i32> {
         process_node_geometry_request(node, self.fragment_tree.borrow().clone())
     }
 
-    #[instrument(skip_all, fields(servo_profiling = true))]
+    #[cfg_attr(
+        feature = "tracing",
+        tracing::instrument(skip_all, fields(servo_profiling = true))
+    )]
     fn query_element_inner_outer_text(
         &self,
         node: script_layout_interface::TrustedNodeAddress,
@@ -316,7 +333,10 @@ impl Layout for LayoutThread {
         None
     }
 
-    #[instrument(skip_all, fields(servo_profiling = true))]
+    #[cfg_attr(
+        feature = "tracing",
+        tracing::instrument(skip_all, fields(servo_profiling = true))
+    )]
     fn query_nodes_from_point(
         &self,
         point: UntypedPoint2D<f32>,
@@ -339,12 +359,18 @@ impl Layout for LayoutThread {
         results.iter().map(|result| result.node.into()).collect()
     }
 
-    #[instrument(skip_all, fields(servo_profiling = true))]
+    #[cfg_attr(
+        feature = "tracing",
+        tracing::instrument(skip_all, fields(servo_profiling = true))
+    )]
     fn query_offset_parent(&self, node: OpaqueNode) -> OffsetParentResponse {
         process_offset_parent_query(node, self.fragment_tree.borrow().clone())
     }
 
-    #[instrument(skip_all, fields(servo_profiling = true))]
+    #[cfg_attr(
+        feature = "tracing",
+        tracing::instrument(skip_all, fields(servo_profiling = true))
+    )]
     fn query_resolved_style(
         &self,
         node: TrustedNodeAddress,
@@ -380,7 +406,10 @@ impl Layout for LayoutThread {
         )
     }
 
-    #[instrument(skip_all, fields(servo_profiling = true))]
+    #[cfg_attr(
+        feature = "tracing",
+        tracing::instrument(skip_all, fields(servo_profiling = true))
+    )]
     fn query_resolved_font_style(
         &self,
         node: TrustedNodeAddress,
@@ -413,12 +442,18 @@ impl Layout for LayoutThread {
         )
     }
 
-    #[instrument(skip_all, fields(servo_profiling = true))]
+    #[cfg_attr(
+        feature = "tracing",
+        tracing::instrument(skip_all, fields(servo_profiling = true))
+    )]
     fn query_scrolling_area(&self, node: Option<OpaqueNode>) -> UntypedRect<i32> {
         process_node_scroll_area_request(node, self.fragment_tree.borrow().clone())
     }
 
-    #[instrument(skip_all, fields(servo_profiling = true))]
+    #[cfg_attr(
+        feature = "tracing",
+        tracing::instrument(skip_all, fields(servo_profiling = true))
+    )]
     fn query_text_indext(
         &self,
         node: OpaqueNode,
@@ -663,7 +698,10 @@ impl LayoutThread {
     }
 
     /// The high-level routine that performs layout.
-    #[instrument(skip_all, fields(servo_profiling = true))]
+    #[cfg_attr(
+        feature = "tracing",
+        tracing::instrument(skip_all, fields(servo_profiling = true))
+    )]
     fn handle_reflow(&mut self, data: &mut ScriptReflowResult) {
         let document = unsafe { ServoLayoutNode::new(&data.document) };
         let document = document.as_document().unwrap();
@@ -783,7 +821,13 @@ impl LayoutThread {
         };
 
         if token.should_traverse() {
-            let span = span!(Level::TRACE, "driver::traverse_dom", servo_profiling = true);
+            #[cfg(feature = "tracing")]
+            let span = tracing::span!(
+                tracing::Level::TRACE,
+                "driver::traverse_dom",
+                servo_profiling = true
+            );
+            #[cfg(feature = "tracing")]
             let _enter = span.enter();
             let dirty_root: ServoLayoutNode =
                 driver::traverse_dom(&traversal, token, rayon_pool).as_node();

components/servo/Cargo.toml

@@ -24,6 +24,7 @@ no-wgl = ["mozangle/egl", "mozangle/build_dlls", "surfman/sm-angle-default"]
 dynamic_freetype = ["webrender/dynamic_freetype"]
 profilemozjs = ["script/profilemozjs"]
 refcell_backtrace = ["script/refcell_backtrace"]
+tracing = ["dep:tracing", "compositing/tracing", "constellation/tracing", "fonts/tracing", "layout_thread_2020/tracing"]
 webdriver = ["webdriver_server"]
 webgl_backtrace = [
     "script/webgl_backtrace",
@@ -76,12 +77,12 @@ sparkle = { workspace = true }
 style = { workspace = true }
 style_traits = { workspace = true }
 surfman = { workspace = true }
+tracing = { workspace = true, optional = true }
 webdriver_server = { path = "../webdriver_server", optional = true }
 webgpu = { path = "../webgpu" }
 webrender = { workspace = true }
 webrender_api = { workspace = true }
 webrender_traits = { workspace = true }
-tracing = { workspace = true }
 webxr = { git = "https://github.com/servo/webxr" }
 webxr-api = { git = "https://github.com/servo/webxr" }
 

components/servo/lib.rs

@@ -224,7 +224,10 @@ impl<Window> Servo<Window>
 where
     Window: WindowMethods + 'static + ?Sized,
 {
-    #[tracing::instrument(skip(embedder, window), fields(servo_profiling = true))]
+    #[cfg_attr(
+        feature = "tracing",
+        tracing::instrument(skip(embedder, window), fields(servo_profiling = true))
+    )]
     pub fn new(
         mut embedder: Box<dyn EmbedderMethods>,
         window: Rc<Window>,

ports/servoshell/Cargo.toml

@@ -49,7 +49,7 @@ multiview = ["libservo/multiview"]
 native-bluetooth = ["libservo/native-bluetooth"]
 profilemozjs = ["libservo/profilemozjs"]
 refcell_backtrace = ["libservo/refcell_backtrace"]
-tracing = ["dep:tracing", "dep:tracing-subscriber"]
+tracing = ["dep:tracing", "dep:tracing-subscriber", "libservo/tracing"]
 tracing-hitrace = ["tracing", "dep:hitrace"]
 tracing-perfetto = ["tracing", "dep:tracing-perfetto"]
 webdriver = ["libservo/webdriver"]