metrics/
lib.rs

1/* This Source Code Form is subject to the terms of the Mozilla Public
2 * License, v. 2.0. If a copy of the MPL was not distributed with this
3 * file, You can obtain one at https://mozilla.org/MPL/2.0/. */
4
5use std::cell::Cell;
6use std::cmp::Ordering;
7use std::time::Duration;
8
9use malloc_size_of_derive::MallocSizeOf;
10use profile_traits::time::{
11    ProfilerCategory, ProfilerChan, TimerMetadata, TimerMetadataFrameType, TimerMetadataReflowType,
12    send_profile_data,
13};
14use script_traits::ProgressiveWebMetricType;
15use servo_base::cross_process_instant::CrossProcessInstant;
16use servo_base::id::LCPCandidateID;
17use servo_config::opts::{self, DiagnosticsLoggingOption};
18use servo_url::ServoUrl;
19
20/// TODO make this configurable
21/// maximum task time is 50ms (in ns)
22pub const MAX_TASK_NS: u128 = 50000000;
23/// 10 second window
24const INTERACTIVE_WINDOW_SECONDS: Duration = Duration::from_secs(10);
25
26pub trait ToMs<T> {
27    fn to_ms(&self) -> T;
28}
29
30impl ToMs<f64> for u64 {
31    fn to_ms(&self) -> f64 {
32        *self as f64 / 1000000.
33    }
34}
35
36fn set_metric(
37    pwm: &ProgressiveWebMetrics,
38    metadata: Option<TimerMetadata>,
39    metric_type: ProgressiveWebMetricType,
40    category: ProfilerCategory,
41    attr: &Cell<Option<CrossProcessInstant>>,
42    metric_time: CrossProcessInstant,
43    url: &ServoUrl,
44) {
45    attr.set(Some(metric_time));
46
47    // Send the metric to the time profiler.
48    send_profile_data(
49        category,
50        metadata,
51        pwm.time_profiler_chan(),
52        metric_time,
53        metric_time,
54    );
55
56    if opts::get()
57        .debug
58        .is_enabled(DiagnosticsLoggingOption::ProgressiveWebMetrics)
59    {
60        let navigation_start = pwm
61            .navigation_start()
62            .unwrap_or_else(CrossProcessInstant::epoch);
63        let duration = (metric_time - navigation_start).as_seconds_f64();
64        println!("{url:?} {metric_type:?} {duration:?}s");
65    }
66}
67
68/// A data structure to track web metrics dfined in various specifications:
69///
70///  - <https://w3c.github.io/paint-timing/>
71///  - <https://github.com/WICG/time-to-interactive> / <https://github.com/GoogleChrome/lighthouse/issues/27>
72///
73///  We can look at three different metrics here:
74///    - navigation start -> visually ready (dom content loaded)
75///    - navigation start -> thread ready (main thread available)
76///    - visually ready -> thread ready
77#[derive(MallocSizeOf)]
78pub struct ProgressiveWebMetrics {
79    /// Whether or not this metric is for an `<iframe>` or a top level frame.
80    frame_type: TimerMetadataFrameType,
81    /// when we navigated to the page
82    navigation_start: Option<CrossProcessInstant>,
83    /// indicates if the page is visually ready
84    dom_content_loaded: Cell<Option<CrossProcessInstant>>,
85    /// main thread is available -- there's been a 10s window with no tasks longer than 50ms
86    main_thread_available: Cell<Option<CrossProcessInstant>>,
87    // max(main_thread_available, dom_content_loaded)
88    time_to_interactive: Cell<Option<CrossProcessInstant>>,
89    /// The first paint of a particular document.
90    /// TODO(mrobinson): It's unclear if this particular metric is reflected in the specification.
91    ///
92    /// See <https://w3c.github.io/paint-timing/#sec-reporting-paint-timing>.
93    first_paint: Cell<Option<CrossProcessInstant>>,
94    /// The first "contentful" paint of a particular document.
95    ///
96    /// See <https://w3c.github.io/paint-timing/#first-contentful-paint>
97    first_contentful_paint: Cell<Option<CrossProcessInstant>>,
98    /// The time at which the largest contentful paint was rendered.
99    ///
100    /// See <https://www.w3.org/TR/largest-contentful-paint/>
101    largest_contentful_paint: Cell<Option<CrossProcessInstant>>,
102    time_profiler_chan: ProfilerChan,
103    url: ServoUrl,
104}
105
106#[derive(Clone, Copy, Debug, MallocSizeOf)]
107pub struct InteractiveWindow {
108    start: CrossProcessInstant,
109}
110
111impl Default for InteractiveWindow {
112    fn default() -> Self {
113        Self {
114            start: CrossProcessInstant::now(),
115        }
116    }
117}
118
119impl InteractiveWindow {
120    // We need to either start or restart the 10s window
121    //   start: we've added a new document
122    //   restart: there was a task > 50ms
123    //   not all documents are interactive
124    pub fn start_window(&mut self) {
125        self.start = CrossProcessInstant::now();
126    }
127
128    /// check if 10s has elapsed since start
129    pub fn needs_check(&self) -> bool {
130        CrossProcessInstant::now() - self.start > INTERACTIVE_WINDOW_SECONDS
131    }
132
133    pub fn get_start(&self) -> CrossProcessInstant {
134        self.start
135    }
136}
137
138#[derive(Debug)]
139pub enum InteractiveFlag {
140    DOMContentLoaded,
141    TimeToInteractive(CrossProcessInstant),
142}
143
144impl ProgressiveWebMetrics {
145    pub fn new(
146        time_profiler_chan: ProfilerChan,
147        url: ServoUrl,
148        frame_type: TimerMetadataFrameType,
149    ) -> ProgressiveWebMetrics {
150        ProgressiveWebMetrics {
151            frame_type,
152            navigation_start: None,
153            dom_content_loaded: Cell::new(None),
154            main_thread_available: Cell::new(None),
155            time_to_interactive: Cell::new(None),
156            first_paint: Cell::new(None),
157            first_contentful_paint: Cell::new(None),
158            largest_contentful_paint: Cell::new(None),
159            time_profiler_chan,
160            url,
161        }
162    }
163
164    fn make_metadata(&self, first_reflow: bool) -> TimerMetadata {
165        TimerMetadata {
166            url: self.url.to_string(),
167            iframe: self.frame_type.clone(),
168            incremental: match first_reflow {
169                true => TimerMetadataReflowType::FirstReflow,
170                false => TimerMetadataReflowType::Incremental,
171            },
172        }
173    }
174
175    pub fn set_dom_content_loaded(&self) {
176        if self.dom_content_loaded.get().is_none() {
177            self.dom_content_loaded
178                .set(Some(CrossProcessInstant::now()));
179        }
180    }
181
182    pub fn set_main_thread_available(&self, time: CrossProcessInstant) {
183        if self.main_thread_available.get().is_none() {
184            self.main_thread_available.set(Some(time));
185        }
186    }
187
188    pub fn dom_content_loaded(&self) -> Option<CrossProcessInstant> {
189        self.dom_content_loaded.get()
190    }
191
192    pub fn first_paint(&self) -> Option<CrossProcessInstant> {
193        self.first_paint.get()
194    }
195
196    pub fn first_contentful_paint(&self) -> Option<CrossProcessInstant> {
197        self.first_contentful_paint.get()
198    }
199
200    pub fn largest_contentful_paint(&self) -> Option<CrossProcessInstant> {
201        self.largest_contentful_paint.get()
202    }
203
204    pub fn main_thread_available(&self) -> Option<CrossProcessInstant> {
205        self.main_thread_available.get()
206    }
207
208    pub fn set_first_paint(&self, paint_time: CrossProcessInstant, first_reflow: bool) {
209        set_metric(
210            self,
211            Some(self.make_metadata(first_reflow)),
212            ProgressiveWebMetricType::FirstPaint,
213            ProfilerCategory::TimeToFirstPaint,
214            &self.first_paint,
215            paint_time,
216            &self.url,
217        );
218    }
219
220    pub fn set_first_contentful_paint(&self, paint_time: CrossProcessInstant, first_reflow: bool) {
221        set_metric(
222            self,
223            Some(self.make_metadata(first_reflow)),
224            ProgressiveWebMetricType::FirstContentfulPaint,
225            ProfilerCategory::TimeToFirstContentfulPaint,
226            &self.first_contentful_paint,
227            paint_time,
228            &self.url,
229        );
230    }
231
232    pub fn set_largest_contentful_paint(
233        &self,
234        id: LCPCandidateID,
235        paint_time: CrossProcessInstant,
236    ) {
237        set_metric(
238            self,
239            Some(self.make_metadata(false)),
240            ProgressiveWebMetricType::LargestContentfulPaint { id },
241            ProfilerCategory::TimeToLargestContentfulPaint,
242            &self.largest_contentful_paint,
243            paint_time,
244            &self.url,
245        );
246    }
247
248    // can set either dlc or tti first, but both must be set to actually calc metric
249    // when the second is set, set_tti is called with appropriate time
250    pub fn maybe_set_tti(&self, metric: InteractiveFlag) {
251        if self.get_tti().is_some() {
252            return;
253        }
254        match metric {
255            InteractiveFlag::DOMContentLoaded => self.set_dom_content_loaded(),
256            InteractiveFlag::TimeToInteractive(time) => self.set_main_thread_available(time),
257        }
258
259        let dcl = self.dom_content_loaded.get();
260        let mta = self.main_thread_available.get();
261        let (dcl, mta) = match (dcl, mta) {
262            (Some(dcl), Some(mta)) => (dcl, mta),
263            _ => return,
264        };
265        let metric_time = match dcl.partial_cmp(&mta) {
266            Some(Ordering::Less) => mta,
267            Some(_) => dcl,
268            None => panic!("no ordering possible. something bad happened"),
269        };
270        set_metric(
271            self,
272            Some(self.make_metadata(true)),
273            ProgressiveWebMetricType::TimeToInteractive,
274            ProfilerCategory::TimeToInteractive,
275            &self.time_to_interactive,
276            metric_time,
277            &self.url,
278        );
279    }
280
281    pub fn get_tti(&self) -> Option<CrossProcessInstant> {
282        self.time_to_interactive.get()
283    }
284
285    pub fn needs_tti(&self) -> bool {
286        self.get_tti().is_none()
287    }
288
289    pub fn navigation_start(&self) -> Option<CrossProcessInstant> {
290        self.navigation_start
291    }
292
293    pub fn set_navigation_start(&mut self, time: CrossProcessInstant) {
294        self.navigation_start = Some(time);
295    }
296
297    pub fn time_profiler_chan(&self) -> &ProfilerChan {
298        &self.time_profiler_chan
299    }
300}
301
302#[cfg(test)]
303mod test {
304    use servo_base::generic_channel;
305
306    use super::*;
307
308    fn test_metrics() -> ProgressiveWebMetrics {
309        let (sender, _) = generic_channel::channel().unwrap();
310        let profiler_chan = ProfilerChan(Some(sender));
311        let mut metrics = ProgressiveWebMetrics::new(
312            profiler_chan,
313            ServoUrl::parse("about:blank").unwrap(),
314            TimerMetadataFrameType::RootWindow,
315        );
316
317        assert!((&metrics).navigation_start().is_none());
318        assert!(metrics.get_tti().is_none());
319        assert!(metrics.first_contentful_paint().is_none());
320        assert!(metrics.first_paint().is_none());
321
322        metrics.set_navigation_start(CrossProcessInstant::now());
323
324        metrics
325    }
326
327    #[test]
328    fn test_set_dcl() {
329        let metrics = test_metrics();
330        metrics.maybe_set_tti(InteractiveFlag::DOMContentLoaded);
331        let dcl = metrics.dom_content_loaded();
332        assert!(dcl.is_some());
333
334        // try to overwrite
335        metrics.maybe_set_tti(InteractiveFlag::DOMContentLoaded);
336        assert_eq!(metrics.dom_content_loaded(), dcl);
337        assert_eq!(metrics.get_tti(), None);
338    }
339
340    #[test]
341    fn test_set_mta() {
342        let metrics = test_metrics();
343        let now = CrossProcessInstant::now();
344        metrics.maybe_set_tti(InteractiveFlag::TimeToInteractive(now));
345        let main_thread_available_time = metrics.main_thread_available();
346        assert!(main_thread_available_time.is_some());
347        assert_eq!(main_thread_available_time, Some(now));
348
349        // try to overwrite
350        metrics.maybe_set_tti(InteractiveFlag::TimeToInteractive(
351            CrossProcessInstant::now(),
352        ));
353        assert_eq!(metrics.main_thread_available(), main_thread_available_time);
354        assert_eq!(metrics.get_tti(), None);
355    }
356
357    #[test]
358    fn test_set_tti_dcl() {
359        let metrics = test_metrics();
360        let now = CrossProcessInstant::now();
361        metrics.maybe_set_tti(InteractiveFlag::TimeToInteractive(now));
362        let main_thread_available_time = metrics.main_thread_available();
363        assert!(main_thread_available_time.is_some());
364
365        metrics.maybe_set_tti(InteractiveFlag::DOMContentLoaded);
366        let dom_content_loaded_time = metrics.dom_content_loaded();
367        assert!(dom_content_loaded_time.is_some());
368
369        assert_eq!(metrics.get_tti(), dom_content_loaded_time);
370    }
371
372    #[test]
373    fn test_set_tti_mta() {
374        let metrics = test_metrics();
375        metrics.maybe_set_tti(InteractiveFlag::DOMContentLoaded);
376        let dcl = metrics.dom_content_loaded();
377        assert!(dcl.is_some());
378
379        let time = CrossProcessInstant::now();
380        metrics.maybe_set_tti(InteractiveFlag::TimeToInteractive(time));
381        let mta = metrics.main_thread_available();
382        assert!(mta.is_some());
383
384        assert_eq!(metrics.get_tti(), mta);
385    }
386
387    #[test]
388    fn test_first_paint_setter() {
389        let metrics = test_metrics();
390        metrics.set_first_paint(CrossProcessInstant::now(), false);
391        assert!(metrics.first_paint().is_some());
392    }
393
394    #[test]
395    fn test_first_contentful_paint_setter() {
396        let metrics = test_metrics();
397        metrics.set_first_contentful_paint(CrossProcessInstant::now(), false);
398        assert!(metrics.first_contentful_paint().is_some());
399    }
400}
metrics/lib.rs

metrics/
lib.rs
