Bug 1747138 - Breakdown CPU and GPU time by process type, r=chutten,gsvelto

Differential Revision: https://phabricator.services.mozilla.com/D134441

dom/base/nsContentUtils.cpp

@@ -81,6 +81,7 @@
 #include "mozilla/EventQueue.h"
 #include "mozilla/EventStateManager.h"
 #include "mozilla/FlushType.h"
+#include "mozilla/FOGIPC.h"
 #include "mozilla/HTMLEditor.h"
 #include "mozilla/HangAnnotations.h"
 #include "mozilla/IMEStateManager.h"
@@ -10117,8 +10118,14 @@ nsContentUtils::UserInteractionObserver::Observe(nsISupports* aSubject,
                                                  const char* aTopic,
                                                  const char16_t* aData) {
   if (!strcmp(aTopic, kUserInteractionInactive)) {
+    if (sUserActive && XRE_IsParentProcess()) {
+      glean::RecordPowerMetrics();
+    }
     sUserActive = false;
   } else if (!strcmp(aTopic, kUserInteractionActive)) {
+    if (!sUserActive && XRE_IsParentProcess()) {
+      glean::RecordPowerMetrics();
+    }
     sUserActive = true;
   } else {
     NS_WARNING("Unexpected observer notification");

dom/ipc/ContentChild.cpp

@@ -2839,6 +2839,12 @@ mozilla::ipc::IPCResult ContentChild::RecvNotifyProcessPriorityChanged(
                       ProcessPriorityToString(mProcessPriority)),
                   ProfilerString8View::WrapNullTerminatedString(
                       ProcessPriorityToString(aPriority)));
+
+  // Record FOG data before the priority change.
+  // Ignore the change if it's the first time we set the process priority.
+  if (mProcessPriority != hal::PROCESS_PRIORITY_UNKNOWN) {
+    glean::RecordPowerMetrics();
+  }
   mProcessPriority = aPriority;
 
   os->NotifyObservers(static_cast<nsIPropertyBag2*>(props),

dom/ipc/ContentChild.h

@@ -834,6 +834,8 @@ class ContentChild final : public PContentChild,
       BrowsingContext* aStartingAt,
       const DispatchBeforeUnloadToSubtreeResolver& aResolver);
 
+  hal::ProcessPriority GetProcessPriority() const { return mProcessPriority; }
+
  private:
   mozilla::ipc::IPCResult RecvFlushFOGData(FlushFOGDataResolver&& aResolver);
 

dom/ipc/ProcessPriorityManager.cpp

@@ -172,6 +172,7 @@ class ProcessPriorityManagerImpl final : public nsIObserver,
 
   static void StaticInit();
   static bool PrefsEnabled();
+  static void SetProcessPriorityIfEnabled(int aPid, ProcessPriority aPriority);
   static bool TestMode();
 
   NS_DECL_ISUPPORTS
@@ -365,6 +366,17 @@ bool ProcessPriorityManagerImpl::PrefsEnabled() {
          !StaticPrefs::dom_ipc_tabs_disabled();
 }
 
+/* static */
+void ProcessPriorityManagerImpl::SetProcessPriorityIfEnabled(
+    int aPid, ProcessPriority aPriority) {
+  // The preference doesn't disable the process priority manager, but only its
+  // effect. This way the IPCs still happen and can be used to collect telemetry
+  // about CPU use.
+  if (PrefsEnabled()) {
+    hal::SetProcessPriority(aPid, aPriority);
+  }
+}
+
 /* static */
 bool ProcessPriorityManagerImpl::TestMode() {
   return StaticPrefs::dom_ipc_processPriorityManager_testMode();
@@ -382,20 +394,13 @@ void ProcessPriorityManagerImpl::StaticInit() {
     return;
   }
 
-  // If IPC tabs aren't enabled at startup, don't bother with any of this.
-  if (!PrefsEnabled()) {
-    LOG("InitProcessPriorityManager bailing due to prefs.");
-
-    // Run StaticInit() again if the prefs change.  We don't expect this to
-    // happen in normal operation, but it happens during testing.
-    if (!sPrefListenersRegistered) {
-      sPrefListenersRegistered = true;
-      Preferences::RegisterCallback(PrefChangedCallback,
-                                    "dom.ipc.processPriorityManager.enabled");
-      Preferences::RegisterCallback(PrefChangedCallback,
-                                    "dom.ipc.tabs.disabled");
-    }
-    return;
+  // Run StaticInit() again if the prefs change.  We don't expect this to
+  // happen in normal operation, but it happens during testing.
+  if (!sPrefListenersRegistered) {
+    sPrefListenersRegistered = true;
+    Preferences::RegisterCallback(PrefChangedCallback,
+                                  "dom.ipc.processPriorityManager.enabled");
+    Preferences::RegisterCallback(PrefChangedCallback, "dom.ipc.tabs.disabled");
   }
 
   sInitialized = true;
@@ -426,7 +431,7 @@ void ProcessPriorityManagerImpl::Init() {
   // The parent process's priority never changes; set it here and then forget
   // about it. We'll manage only subprocesses' priorities using the process
   // priority manager.
-  hal::SetProcessPriority(getpid(), PROCESS_PRIORITY_PARENT_PROCESS);
+  SetProcessPriorityIfEnabled(getpid(), PROCESS_PRIORITY_PARENT_PROCESS);
 
   nsCOMPtr<nsIObserverService> os = services::GetObserverService();
   if (os) {
@@ -762,8 +767,7 @@ void ParticularProcessPriorityManager::SetPriorityNow(
     return;
   }
 
-  if (!ProcessPriorityManagerImpl::PrefsEnabled() || !mContentParent ||
-      mPriority == aPriority) {
+  if (!mContentParent || mPriority == aPriority) {
     return;
   }
 
@@ -794,7 +798,7 @@ void ParticularProcessPriorityManager::SetPriorityNow(
         Telemetry::ScalarID::DOM_CONTENTPROCESS_OS_PRIORITY_LOWERED, 1);
   }
 
-  hal::SetProcessPriority(Pid(), mPriority);
+  ProcessPriorityManagerImpl::SetProcessPriorityIfEnabled(Pid(), mPriority);
 
   if (oldPriority != mPriority) {
     ProcessPriorityManagerImpl::GetSingleton()->NotifyProcessPriorityChanged(

dom/media/test/browser/browser_telemetry_video_hardware_decoding_support.js

@@ -14,6 +14,9 @@ add_task(async function setupTestingPref() {
   });
 });
 
+const ALL_SCALAR = "media.video_hardware_decoding_support";
+const HD_SCALAR = "media.video_hd_hardware_decoding_support";
+
 add_task(async function testVideoCodecs() {
   // There are still other video codecs, but we only care about these popular
   // codec types.
@@ -24,8 +27,6 @@ add_task(async function testVideoCodecs() {
     { fileName: "av1.mp4", type: "video/av1" },
     { fileName: "bunny_hd_5s.mp4", type: "video/avc", hd: true },
   ];
-  const ALL_SCALAR = "media.video_hardware_decoding_support";
-  const HD_SCALAR = "media.video_hd_hardware_decoding_support";
 
   for (const file of testFiles) {
     const { fileName, type, hd } = file;
@@ -76,7 +77,12 @@ add_task(async function testAudioCodecs() {
     await audio.play();
     let snapshot = Services.telemetry.getSnapshotForKeyedScalars("main", false)
       .parent;
-    ok(!snapshot, `Did not record scalar for ${file}`);
+    ok(
+      !snapshot ||
+        (!snapshot.hasOwnProperty(ALL_SCALAR) &&
+          !snapshot.hasOwnProperty(HD_SCALAR)),
+      `Did not record scalar for ${file}`
+    );
     audio.src = "";
   }
 });

hal/HalWakeLock.cpp

@@ -6,6 +6,7 @@
 
 #include "Hal.h"
 #include "base/process_util.h"
+#include "mozilla/FOGIPC.h"
 #include "mozilla/HalWakeLock.h"
 #include "mozilla/Services.h"
 #include "mozilla/StaticPtr.h"
@@ -199,6 +200,14 @@ void ModifyWakeLock(const nsAString& aTopic, hal::WakeLockControl aLockAdjust,
 
   WakeLockState oldState =
       ComputeWakeLockState(totalCount.numLocks, totalCount.numHidden);
+
+  if (ComputeWakeLockState(totalCount.numLocks + aLockAdjust,
+                           totalCount.numHidden + aHiddenAdjust) != oldState &&
+      (aTopic.Equals(u"video-playing"_ns) ||
+       aTopic.Equals(u"audio-playing"_ns))) {
+    glean::RecordPowerMetrics();
+  }
+
   bool processWasLocked = processCount.numLocks > 0;
 
   processCount.numLocks += aLockAdjust;
@@ -235,6 +244,13 @@ void GetWakeLockInfo(const nsAString& aTopic,
     return;
   }
 
+  if (!sLockTable) {
+    // This can happen during some gtests.
+    NS_WARNING("Attempting to get wake lock information before initialization");
+    *aWakeLockInfo = WakeLockInformation();
+    return;
+  }
+
   ProcessLockTable* table = sLockTable->Get(aTopic);
   if (!table) {
     *aWakeLockInfo = WakeLockInfoFromLockCount(aTopic, LockCount());

toolkit/components/glean/ipc/FOGIPC.cpp

@@ -14,6 +14,7 @@
 #include "mozilla/gfx/GPUChild.h"
 #include "mozilla/gfx/GPUParent.h"
 #include "mozilla/gfx/GPUProcessManager.h"
+#include "mozilla/Hal.h"
 #include "mozilla/MozPromise.h"
 #include "mozilla/net/SocketProcessChild.h"
 #include "mozilla/net/SocketProcessParent.h"
@@ -43,15 +44,68 @@ using FlushFOGDataPromise = mozilla::dom::ContentParent::FlushFOGDataPromise;
 namespace mozilla {
 namespace glean {
 
-static void RecordPowerMetrics() {
+void RecordPowerMetrics() {
   static uint64_t previousCpuTime = 0, previousGpuTime = 0;
 
-  uint64_t cpuTime;
+  uint64_t cpuTime, newCpuTime = 0;
   if (NS_SUCCEEDED(GetCpuTimeSinceProcessStartInMs(&cpuTime)) &&
       cpuTime > previousCpuTime) {
-    uint64_t newCpuTime = cpuTime - previousCpuTime;
-    previousCpuTime += newCpuTime;
+    newCpuTime = cpuTime - previousCpuTime;
+  }
 
+  uint64_t gpuTime, newGpuTime = 0;
+  if (NS_SUCCEEDED(GetGpuTimeSinceProcessStartInMs(&gpuTime)) &&
+      gpuTime > previousGpuTime) {
+    newGpuTime = gpuTime - previousGpuTime;
+  }
+
+  if (!newCpuTime && !newGpuTime) {
+    // Nothing to record.
+    return;
+  }
+
+  // Compute the process type string.
+  nsAutoCString type(XRE_GetProcessTypeString());
+  if (XRE_IsContentProcess()) {
+    auto* cc = dom::ContentChild::GetSingleton();
+    if (cc) {
+      type.Assign(dom::RemoteTypePrefix(cc->GetRemoteType()));
+      if (StringBeginsWith(type, WEB_REMOTE_TYPE)) {
+        type.AssignLiteral("web");
+        switch (cc->GetProcessPriority()) {
+          case hal::PROCESS_PRIORITY_BACKGROUND:
+            type.AppendLiteral(".background");
+            break;
+          case hal::PROCESS_PRIORITY_FOREGROUND:
+            type.AppendLiteral(".foreground");
+            break;
+          case hal::PROCESS_PRIORITY_BACKGROUND_PERCEIVABLE:
+            type.AppendLiteral(".background-perceivable");
+            break;
+          default:
+            break;
+        }
+      }
+    }
+  } else if (XRE_IsParentProcess()) {
+    if (nsContentUtils::GetUserIsInteracting()) {
+      type.AssignLiteral("parent.active");
+    } else {
+      type.AssignLiteral("parent.inactive");
+    }
+    hal::WakeLockInformation info;
+    GetWakeLockInfo(u"video-playing"_ns, &info);
+    if (info.numLocks() != 0 && info.numHidden() < info.numLocks()) {
+      type.AppendLiteral(".playing-video");
+    } else {
+      GetWakeLockInfo(u"audio-playing"_ns, &info);
+      if (info.numLocks()) {
+        type.AppendLiteral(".playing-audio");
+      }
+    }
+  }
+
+  if (newCpuTime) {
     // The counters are reset at least once a day. Assuming all cores are used
     // continuously, an int32 can hold the data for 24.85 cores.
     // This should be fine for now, but may overflow in the future.
@@ -61,19 +115,18 @@ static void RecordPowerMetrics() {
       nNewCpuTime = std::numeric_limits<int32_t>::max();
     }
     power::total_cpu_time_ms.Add(nNewCpuTime);
+    power::cpu_time_per_process_type_ms.Get(type).Add(nNewCpuTime);
+    previousCpuTime += newCpuTime;
   }
 
-  uint64_t gpuTime;
-  if (NS_SUCCEEDED(GetGpuTimeSinceProcessStartInMs(&gpuTime)) &&
-      gpuTime > previousGpuTime) {
-    uint64_t newGpuTime = gpuTime - previousGpuTime;
-    previousGpuTime += newGpuTime;
-
+  if (newGpuTime) {
     int32_t nNewGpuTime = int32_t(newGpuTime);
     if (newGpuTime > std::numeric_limits<int32_t>::max()) {
       nNewGpuTime = std::numeric_limits<int32_t>::max();
     }
-    power::total_gpu_time_ms.Add(int32_t(nNewGpuTime));
+    power::total_gpu_time_ms.Add(nNewGpuTime);
+    power::gpu_time_per_process_type_ms.Get(type).Add(nNewGpuTime);
+    previousGpuTime += newGpuTime;
   }
 }
 

toolkit/components/glean/ipc/FOGIPC.h

@@ -71,6 +71,8 @@ RefPtr<GenericPromise> FlushAndUseFOGData();
 void TestTriggerMetrics(uint32_t processType,
                         const RefPtr<dom::Promise>& promise);
 
+void RecordPowerMetrics();
+
 }  // namespace glean
 }  // namespace mozilla
 

toolkit/components/processtools/metrics.yaml

@@ -13,6 +13,55 @@
 $schema: moz://mozilla.org/schemas/glean/metrics/2-0-0
 
 power:
+  cpu_time_per_process_type_ms:
+    type: labeled_counter
+    description: >
+      CPU time used by each process type in ms.
+    bugs:
+      - https://bugzilla.mozilla.org/show_bug.cgi?id=1747138
+    data_reviews:
+      - https://bugzilla.mozilla.org/show_bug.cgi?id=1747138
+    data_sensitivity:
+      - technical
+    notification_emails:
+      - florian@mozilla.com
+    expires: never
+    labels: &per_process_type_labels
+      - parent.active
+      - parent.active.playing-audio
+      - parent.active.playing-video
+      - parent.inactive
+      - parent.inactive.playing-audio
+      - parent.inactive.playing-video
+      - prealloc
+      - privilegedabout
+      - rdd
+      - socket
+      - web.background
+      - web.background-perceivable
+      - web.foreground
+      - extension
+      - gpu
+      - gmplugin
+      - utility
+    telemetry_mirror: POWER_CPU_TIME_PER_PROCESS_TYPE_MS
+
+  gpu_time_per_process_type_ms:
+    type: labeled_counter
+    description: >
+      GPU time used by each process type in ms.
+    bugs:
+      - https://bugzilla.mozilla.org/show_bug.cgi?id=1747138
+    data_reviews:
+      - https://bugzilla.mozilla.org/show_bug.cgi?id=1747138
+    data_sensitivity:
+      - technical
+    notification_emails:
+      - florian@mozilla.com
+    expires: never
+    labels: *per_process_type_labels
+    telemetry_mirror: POWER_GPU_TIME_PER_PROCESS_TYPE_MS
+
   total_cpu_time_ms:
     type: counter
     description: >
@@ -46,5 +95,3 @@ power:
       - florian@mozilla.com
     expires: never
     telemetry_mirror: POWER_TOTAL_GPU_TIME_MS
-    no_lint:
-      - COMMON_PREFIX

toolkit/components/processtools/tests/browser/browser.ini

@@ -5,5 +5,6 @@ prefs=
 support-files =
   dummy.html
 
+[browser_test_powerMetrics.js]
 [browser_test_procinfo.js]
 skip-if = (ccov && os == "linux") # https://bugzilla.mozilla.org/show_bug.cgi?id=1608080

toolkit/components/processtools/tests/browser/browser_test_powerMetrics.js

@@ -0,0 +1,290 @@
+/* Any copyright is dedicated to the Public Domain.
+ * http://creativecommons.org/publicdomain/zero/1.0/ */
+
+"use strict";
+
+/**
+ * Return a web-based URL for a given file based on the testing directory.
+ * @param {String} fileName
+ *        file that caller wants its web-based url
+ */
+function GetTestWebBasedURL(fileName) {
+  return (
+    getRootDirectory(gTestPath).replace(
+      "chrome://mochitests/content",
+      "http://example.org"
+    ) + fileName
+  );
+}
+
+const kNS_PER_MS = 1000000;
+
+function printProcInfo(procInfo) {
+  info(
+    `  pid: ${procInfo.pid}, type = parent, cpu time = ${procInfo.cpuTime /
+      kNS_PER_MS}ms`
+  );
+  for (let child of procInfo.children) {
+    info(
+      `  pid: ${child.pid}, type = ${child.type}, cpu time = ${child.cpuTime /
+        kNS_PER_MS}ms`
+    );
+  }
+}
+
+// It would be nice to have an API to list all the statically defined labels of
+// a labeled_counter. Hopefully bug 1672273 will help with this.
+const kGleanProcessTypeLabels = [
+  "parent.active",
+  "parent.active.playing-audio",
+  "parent.active.playing-video",
+  "parent.inactive",
+  "parent.inactive.playing-audio",
+  "parent.inactive.playing-video",
+  "prealloc",
+  "privilegedabout",
+  "rdd",
+  "socket",
+  "web.background",
+  "web.background-perceivable",
+  "web.foreground",
+  "extension",
+  "gpu",
+  "gmplugin",
+  "utility",
+  "__other__",
+];
+
+async function getChildCpuTime(pid) {
+  return (await ChromeUtils.requestProcInfo()).children.find(p => p.pid == pid)
+    .cpuTime;
+}
+
+add_task(async () => {
+  // Temporarily open a new foreground tab to make the current tab a background
+  // tab, and burn some CPU time in it while it's in the background.
+  const kBusyWaitForMs = 50;
+  let cpuTimeSpentOnBackgroundTab;
+  let firstBrowser = gBrowser.selectedTab.linkedBrowser;
+  let processPriorityChangedPromise = BrowserTestUtils.contentTopicObserved(
+    firstBrowser.browsingContext,
+    "ipc:process-priority-changed"
+  );
+  await BrowserTestUtils.withNewTab(
+    GetTestWebBasedURL("dummy.html"),
+    async () => {
+      await processPriorityChangedPromise;
+      // We can't be sure that a busy loop lasting for a specific duration
+      // will use the same amount of CPU time, as that would require a core
+      // to be fully available for our busy loop, which is unlikely on single
+      // core hardware.
+      // To be able to have a predictable amount of CPU time used, we need to
+      // check using ChromeUtils.requestProcInfo how much CPU time has actually
+      // been spent.
+      let pid = firstBrowser.frameLoader.remoteTab.osPid;
+      let initalCpuTime = await getChildCpuTime(pid);
+      let afterCpuTime;
+      do {
+        await SpecialPowers.spawn(
+          firstBrowser,
+          [kBusyWaitForMs],
+          async kBusyWaitForMs => {
+            let startTime = Date.now();
+            while (Date.now() - startTime < 10) {
+              // Burn CPU time...
+            }
+          }
+        );
+        afterCpuTime = await getChildCpuTime(pid);
+      } while (afterCpuTime - initalCpuTime < kBusyWaitForMs * kNS_PER_MS);
+      cpuTimeSpentOnBackgroundTab = Math.floor(
+        (afterCpuTime - initalCpuTime) / kNS_PER_MS
+      );
+    }
+  );
+
+  let beforeProcInfo = await ChromeUtils.requestProcInfo();
+  await Services.fog.testFlushAllChildren();
+
+  let cpuTimeByType = {},
+    gpuTimeByType = {};
+  for (let label of kGleanProcessTypeLabels) {
+    cpuTimeByType[label] = Glean.power.cpuTimePerProcessTypeMs[
+      label
+    ].testGetValue();
+    gpuTimeByType[label] = Glean.power.gpuTimePerProcessTypeMs[
+      label
+    ].testGetValue();
+  }
+  let totalCpuTime = Glean.power.totalCpuTimeMs.testGetValue();
+  let totalGpuTime = Glean.power.totalGpuTimeMs.testGetValue();
+
+  let afterProcInfo = await ChromeUtils.requestProcInfo();
+
+  info("CPU time from ProcInfo before calling testFlushAllChildren:");
+  printProcInfo(beforeProcInfo);
+
+  info("CPU time for each label:");
+  let totalCpuTimeByType = 0;
+  for (let label of kGleanProcessTypeLabels) {
+    totalCpuTimeByType += cpuTimeByType[label] ?? 0;
+    info(`  ${label} = ${cpuTimeByType[label]}`);
+  }
+
+  info("CPU time from ProcInfo after calling testFlushAllChildren:");
+  printProcInfo(afterProcInfo);
+
+  Assert.equal(
+    totalCpuTimeByType,
+    totalCpuTime,
+    "The sum of CPU time used by all process types should match totalCpuTimeMs"
+  );
+
+  // In infra the parent process time will be reported as parent.inactive,
+  // but when running the test locally the user might move the mouse a bit.
+  let parentTime =
+    (cpuTimeByType["parent.active"] || 0) +
+    (cpuTimeByType["parent.inactive"] || 0);
+  Assert.greaterOrEqual(
+    parentTime,
+    Math.floor(beforeProcInfo.cpuTime / kNS_PER_MS),
+    "reported parent cpu time should be at least what the first requestProcInfo returned"
+  );
+  Assert.lessOrEqual(
+    parentTime,
+    Math.ceil(afterProcInfo.cpuTime / kNS_PER_MS),
+    "reported parent cpu time should be at most what the second requestProcInfo returned"
+  );
+
+  kGleanProcessTypeLabels
+    .filter(label => label.startsWith("parent.") && label.includes(".playing-"))
+    .forEach(label => {
+      Assert.strictEqual(
+        cpuTimeByType[label],
+        undefined,
+        `no media was played so the CPU time for ${label} should be undefined`
+      );
+    });
+
+  if (beforeProcInfo.children.some(p => p.type == "preallocated")) {
+    Assert.greaterOrEqual(
+      cpuTimeByType.prealloc,
+      Math.floor(
+        beforeProcInfo.children.reduce(
+          (time, p) => time + (p.type == "preallocated" ? p.cpuTime : 0),
+          0
+        ) / kNS_PER_MS
+      ),
+      "reported cpu time for preallocated content processes should be at least the sum of what the first requestProcInfo returned."
+    );
+    // We can't compare with the values returned by the second requestProcInfo
+    // call because one preallocated content processes has been turned into
+    // a normal content process when we opened a tab.
+  } else {
+    info(
+      "no preallocated content process existed when we started our test, but some might have existed before"
+    );
+  }
+
+  if (beforeProcInfo.children.some(p => p.type == "privilegedabout")) {
+    Assert.greaterOrEqual(
+      cpuTimeByType.privilegedabout,
+      1,
+      "we used some CPU time in a foreground tab, but don't know how much as the process might have started as preallocated"
+    );
+  }
+
+  for (let label of [
+    "rdd",
+    "socket",
+    "extension",
+    "gpu",
+    "gmplugin",
+    "utility",
+  ]) {
+    if (!kGleanProcessTypeLabels.includes(label)) {
+      Assert.ok(
+        false,
+        `coding error in the test, ${label} isn't part of ${kGleanProcessTypeLabels.join(
+          ", "
+        )}`
+      );
+    }
+    if (beforeProcInfo.children.some(p => p.type == label)) {
+      Assert.greaterOrEqual(
+        cpuTimeByType[label],
+        Math.floor(
+          beforeProcInfo.children.find(p => p.type == label).cpuTime /
+            kNS_PER_MS
+        ),
+        "reported cpu time for " +
+          label +
+          " process should be at least what the first requestProcInfo returned."
+      );
+      Assert.lessOrEqual(
+        cpuTimeByType[label],
+        Math.ceil(
+          afterProcInfo.children.find(p => p.type == label).cpuTime / kNS_PER_MS
+        ),
+        "reported cpu time for " +
+          label +
+          " process should be at most what the second requestProcInfo returned."
+      );
+    } else {
+      info(
+        "no " +
+          label +
+          " process existed when we started our test, but some might have existed before"
+      );
+    }
+  }
+
+  Assert.greaterOrEqual(
+    cpuTimeByType["web.background"],
+    cpuTimeSpentOnBackgroundTab,
+    "web.background should be at least the time we spent."
+  );
+
+  Assert.greaterOrEqual(
+    cpuTimeByType["web.foreground"],
+    1,
+    "we used some CPU time in a foreground tab, but don't know how much"
+  );
+
+  // We only have web.background-perceivable CPU time if a muted video was
+  // played in a background tab.
+  Assert.strictEqual(
+    cpuTimeByType["web.background-perceivable"],
+    undefined,
+    "CPU time should only be recorded in the web.background-perceivable label"
+  );
+
+  // __other__ should be undefined, if it is not, we have a missing label in the metrics.yaml file.
+  Assert.strictEqual(
+    cpuTimeByType.__other__,
+    undefined,
+    "no CPU time should be recorded in the __other__ label"
+  );
+
+  info("GPU time for each label:");
+  let totalGpuTimeByType = undefined;
+  for (let label of kGleanProcessTypeLabels) {
+    if (gpuTimeByType[label] !== undefined) {
+      totalGpuTimeByType = (totalGpuTimeByType || 0) + gpuTimeByType[label];
+    }
+    info(`  ${label} = ${gpuTimeByType[label]}`);
+  }
+
+  Assert.equal(
+    totalGpuTimeByType,
+    totalGpuTime,
+    "The sum of GPU time used by all process types should match totalGpuTimeMs"
+  );
+
+  // __other__ should be undefined, if it is not, we have a missing label in the metrics.yaml file.
+  Assert.strictEqual(
+    gpuTimeByType.__other__,
+    undefined,
+    "no GPU time should be recorded in the __other__ label"
+  );
+});

toolkit/components/telemetry/Scalars.yaml

@@ -7414,6 +7414,58 @@ contextual.services.quicksuggest:
       - main
 
 power:
+  cpu_time_per_process_type_ms:
+    bug_numbers:
+      - 1747138
+    description: >
+      CPU time used by each process type in ms.
+    expires: never
+    kind: uint
+    notification_emails:
+      - florian@mozilla.com
+    release_channel_collection: opt-out
+    products:
+      - 'firefox'
+    record_in_processes:
+      - 'all'
+    keyed: true
+    keys: &per_process_type_keys
+      - parent.active
+      - parent.active.playing-audio
+      - parent.active.playing-video
+      - parent.inactive
+      - parent.inactive.playing-audio
+      - parent.inactive.playing-video
+      - prealloc
+      - privilegedabout
+      - rdd
+      - socket
+      - web.background
+      - web.background-perceivable
+      - web.foreground
+      - extension
+      - gpu
+      - gmplugin
+      - utility
+
+  gpu_time_per_process_type_ms:
+    bug_numbers:
+      - 1747138
+    description: >
+      GPU time used by each process type in ms.
+    expires: never
+    kind: uint
+    notification_emails:
+      - florian@mozilla.com
+    release_channel_collection: opt-out
+    products:
+      - 'firefox'
+    record_in_processes:
+      - 'main'
+      - 'gpu'
+    keyed: true
+    keys: *per_process_type_keys
+
   total_cpu_time_ms:
     bug_numbers:
       - 1736040