For #18426: record cold start duration telemetry.
Michael Comella
3 years ago
committed by
Michael Comella
parent
2be9fb61d0
commit
ade38246be
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/* This Source Code Form is subject to the terms of the Mozilla Public
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* License, v. 2.0. If a copy of the MPL was not distributed with this
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* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
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package org.mozilla.fenix.perf
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import android.content.Intent
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import android.os.SystemClock
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import android.view.View
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import androidx.core.view.doOnPreDraw
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import mozilla.components.support.base.log.logger.Logger
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import mozilla.components.support.utils.SafeIntent
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import org.mozilla.fenix.GleanMetrics.PerfStartup
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import org.mozilla.fenix.perf.StartupActivityStateProvider.FirstForegroundActivity
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import org.mozilla.fenix.perf.StartupActivityStateProvider.FirstForegroundActivityState
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import org.mozilla.fenix.perf.AppStartReasonProvider.StartReason
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import java.util.concurrent.TimeUnit
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private val logger = Logger("ColdStartupDuration")
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/**
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* A class to record COLD start up telemetry. This class is intended to improve upon our mistakes from the
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* [org.mozilla.fenix.components.metrics.AppStartupTelemetry] class by being simple-to-implement and
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* simple-to-analyze (i.e. works in GLAM) rather than being a "perfect" and comprehensive measurement.
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*
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* This class relies on external state providers like [AppStartReasonProvider] and
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* [StartupActivityStateProvider] that are tricky to implement correctly so take the results with a
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* grain of salt.
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*/
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class ColdStartupDurationTelemetry {
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fun onHomeActivityOnCreate(
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visualCompletenessQueue: VisualCompletenessQueue,
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startReasonProvider: AppStartReasonProvider,
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startupActivityStateProvider: StartupActivityStateProvider,
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safeIntent: SafeIntent,
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rootContainer: View
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) {
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// Optimization: it's expensive to post runnables so we can short-circuit with a subset of the later logic.
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if (startupActivityStateProvider.firstForegroundActivityState ==
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FirstForegroundActivityState.AFTER_FOREGROUND) {
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logger.debug("Not measuring: first foreground activity already backgrounded")
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return
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}
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rootContainer.doOnPreDraw {
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// Optimization: we're running code before the first frame so we want to avoid doing anything
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// expensive as part of the drawing loop. Recording telemetry took 3-7ms on the Moto G5 (a
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// frame is ~16ms) so we defer the expensive work for later by posting a Runnable.
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//
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// We copy the values because their values may change when passed into the handler. It's
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// cheaper to copy the values than copy the objects (= allocation + copy values) so we just
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// copy the values even though this copy could happen incorrectly if these values become objects later.
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val startReason = startReasonProvider.reason
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val firstActivity = startupActivityStateProvider.firstForegroundActivityOfProcess
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val firstActivityState = startupActivityStateProvider.firstForegroundActivityState
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val firstFrameNanos = SystemClock.elapsedRealtimeNanos()
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// On the visual completeness queue, this will report later than posting to the main thread (not
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// ideal for pulling out of automated performance tests) but should delay visual completeness less.
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visualCompletenessQueue.queue.runIfReadyOrQueue {
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if (!isColdStartToThisHomeActivityInstance(startReason, firstActivity, firstActivityState)) {
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logger.debug("Not measuring: this activity isn't both the first foregrounded & HomeActivity")
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return@runIfReadyOrQueue
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}
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recordColdStartupTelemetry(safeIntent, firstFrameNanos)
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}
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}
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}
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private fun isColdStartToThisHomeActivityInstance(
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startReason: StartReason,
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firstForegroundActivity: FirstForegroundActivity,
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firstForegroundActivityState: FirstForegroundActivityState
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): Boolean {
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// This logic is fragile: if an Activity that isn't currently foregrounded is refactored to get
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// temporarily foregrounded (e.g. IntentReceiverActivity) or an interstitial Activity is added
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// that is temporarily foregrounded, we'll no longer detect HomeActivity as the first foregrounded
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// activity and we'll never record telemetry.
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//
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// Because of this, we may not record values in Beta and Release if MigrationDecisionActivity
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// gets foregrounded (I never tested these channels: I think Nightly data is probably good enough for now).
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//
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// What we'd ideally determine is, "Is the final activity during this start up HomeActivity?"
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// However, it's challenging to do so in a robust way so we stick with this simpler solution
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// ("Is the first foregrounded activity during this start up HomeActivity?") despite its flaws.
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val wasProcessStartedBecauseOfAnActivity = startReason == StartReason.ACTIVITY
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val isThisTheFirstForegroundActivity = firstForegroundActivity == FirstForegroundActivity.HOME_ACTIVITY &&
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firstForegroundActivityState == FirstForegroundActivityState.CURRENTLY_FOREGROUNDED
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return wasProcessStartedBecauseOfAnActivity && isThisTheFirstForegroundActivity
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}
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private fun recordColdStartupTelemetry(safeIntent: SafeIntent, firstFrameNanos: Long) {
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// This code duplicates the logic for determining how we should handle this intent which
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// could result in inconsistent results: e.g. the browser might get a VIEW intent but it's
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// malformed so the app treats it as a MAIN intent but here we record VIEW. However, the
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// logic for determining the end state is distributed and buried & inspecting the end state
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// is fragile (e.g. if the browser was open, was it a MAIN w/ session restore or VIEW?) so we
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// use this simpler solution even if it's imperfect. Hopefully, the success cases will
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// outnumber the edge cases into statistical insignificance.
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val (metric, typeForLog) = when (safeIntent.action) {
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Intent.ACTION_MAIN -> Pair(PerfStartup.coldMainAppToFirstFrame, "MAIN")
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Intent.ACTION_VIEW -> Pair(PerfStartup.coldViewAppToFirstFrame, "VIEW")
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else -> Pair(PerfStartup.coldUnknwnAppToFirstFrame, "UNKNOWN")
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}
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val startNanos = StartupTimeline.frameworkStartMeasurement.applicationInitNanos
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val durationMillis = TimeUnit.NANOSECONDS.toMillis(firstFrameNanos - startNanos)
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metric.accumulateSamples(longArrayOf(durationMillis))
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logger.info("COLD $typeForLog Application.<init> to first frame: $durationMillis ms")
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}
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}
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