gecko-dev/toolkit/components/telemetry/tests/browser/browser_TelemetryGC.js

"use strict";

/*
 *********************************************************************************
 *                                                                               *
 *                                  WARNING                                      *
 *                                                                               *
 * If you adjust any of the constants here (slice limit, number of keys, etc.)   *
 * make sure to update the JSON schema at:                                       *
 * https://github.com/mozilla-services/mozilla-pipeline-schemas/blob/master/     *
 * telemetry/main.schema.json                                                    *
 *                                                                               *
 * Otherwise, pings may be dropped by the telemetry backend!                     *
 *                                                                               *
 ********************************************************************************/

const {GCTelemetry} = ChromeUtils.import("resource://gre/modules/GCTelemetry.jsm");

function check(entries) {
  const FIELDS = ["random", "worst"];

  // Check that all FIELDS are in |entries|.
  for (let f of FIELDS) {
    ok(f in entries, `${f} found in entries`);
  }

  // Check that only FIELDS are in |entries|.
  for (let k of Object.keys(entries)) {
    ok(FIELDS.includes(k), `${k} found in FIELDS`);
  }

  for (let f of FIELDS) {
    ok(Array.isArray(entries[f]), "have an array of GCs");

    ok(entries[f].length <= 2, "not too many GCs");

    for (let gc of entries[f]) {
      isnot(gc, null, "GC is non-null");

      ok(Object.keys(gc).length <= 24, "number of keys in GC is not too large");

      // Sanity check the GC data.
      ok("status" in gc, "status field present");
      is(gc.status, "completed", "status field correct");
      ok("total_time" in gc, "total_time field present");
      ok("max_pause" in gc, "max_pause field present");

      ok("slices_list" in gc, "slices_list field present");
      ok(Array.isArray(gc.slices_list), "slices_list is an array");
      ok(gc.slices_list.length > 0, "slices_list array non-empty");
      ok(gc.slices_list.length <= 4, "slices_list array is not too long");

      ok("totals" in gc, "totals field present");
      is(typeof(gc.totals), "object", "totals is an object");
      ok(Object.keys(gc.totals).length <= 65, "totals array is not too long");

      // Make sure we don't skip any big objects.
      for (let key in gc) {
        if (key != "slices_list" && key != "totals") {
          isnot(typeof(gc[key]), "object", `${key} property should be primitive`);
        }
      }

      let phases = new Set();

      for (let slice of gc.slices_list) {
        ok(Object.keys(slice).length <= 12, "slice is not too large");

        ok("pause" in slice, "pause field present in slice");
        ok("reason" in slice, "reason field present in slice");
        ok("times" in slice, "times field present in slice");

        // Make sure we don't skip any big objects.
        for (let key in slice) {
          if (key != "times") {
            isnot(typeof(slice[key]), "object", `${key} property should be primitive`);
          }
        }

        ok(Object.keys(slice.times).length <= 65, "no more than 65 phases");

        for (let phase in slice.times) {
          phases.add(phase);
          is(typeof(slice.times[phase]), "number", `${phase} property should be a number`);
        }
      }

      let totals = gc.totals;
      // Make sure we don't skip any big objects.
      for (let phase in totals) {
        is(typeof(totals[phase]), "number", `${phase} property should be a number`);
      }

      for (let phase of phases) {
        ok(phase in totals, `${phase} is in totals`);
      }
    }
  }
}

add_task(async function test() {
  let multiprocess = Services.appinfo.browserTabsRemoteAutostart;

  // Set these prefs to ensure that we get measurements.
  await SpecialPowers.pushPrefEnv({"set": [["javascript.options.mem.notify", true]]});

  function runRemote(f) {
    gBrowser.selectedBrowser.messageManager.loadFrameScript(`data:,(${f})()`, false);
  }

  // These are available to frame scripts.
  /* global addMessageListener:false, removeMessageListener: false */
  function initScript() {
    const {GCTelemetry} = ChromeUtils.import("resource://gre/modules/GCTelemetry.jsm");

    /*
     * Don't shut down GC telemetry if it was already running before the test!
     * Note: We need to use a multiline comment here since this code is turned into a data: URI.
     */
    let shutdown = GCTelemetry.init();

    function listener() {
      removeMessageListener("GCTelemTest:Shutdown", listener);
      if (shutdown) {
        GCTelemetry.shutdown();
      }
    }
    addMessageListener("GCTelemTest:Shutdown", listener);
  }

  if (multiprocess) {
    runRemote(initScript);
  }

  // Don't shut down GC telemetry if it was already running before the test!
  let shutdown = GCTelemetry.init();
  registerCleanupFunction(() => {
    if (shutdown) {
      GCTelemetry.shutdown();
    }

    gBrowser.selectedBrowser.messageManager.sendAsyncMessage("GCTelemTest:Shutdown");
  });

  let localPromise = new Promise(resolve => {
    function obs() {
      Services.obs.removeObserver(obs, "garbage-collection-statistics");
      resolve();
    }
    Services.obs.addObserver(obs, "garbage-collection-statistics");
  });

  let remotePromise;
  if (multiprocess) {
    remotePromise = new Promise(resolve => {
      function obs() {
        Services.ppmm.removeMessageListener("Telemetry:GCStatistics", obs);
        resolve();
      }
      Services.ppmm.addMessageListener("Telemetry:GCStatistics", obs);
    });
  } else {
    remotePromise = Promise.resolve();
  }

  // Make sure we have a GC to work with in both processes.
  Cu.forceGC();
  if (multiprocess) {
    runRemote(() => Cu.forceGC());
  }

  info("Waiting for GCs");

  await Promise.all([localPromise, remotePromise]);

  let localEntries = GCTelemetry.entries("main", true);
  let remoteEntries = multiprocess ? GCTelemetry.entries("content", true) : localEntries;

  check(localEntries);
  check(remoteEntries);

  localEntries = GCTelemetry.entries("main", false);
  remoteEntries = multiprocess ? GCTelemetry.entries("content", false) : localEntries;

  is(localEntries.random.length, 0, "no random GCs after reset");
  is(localEntries.worst.length, 0, "no worst GCs after reset");

  is(remoteEntries.random.length, 0, "no random GCs after reset");
  is(remoteEntries.worst.length, 0, "no worst GCs after reset");
});