Function statsForTimeRange

performance-tests/trace-parser.mjs:348–401

(events, startTime, endTime)

}

function statsForTimeRange(events, startTime, endTime) {
  if (!events.length) {
    return { idle: endTime - startTime };
  }

  buildRangeStatsCacheIfNeeded(events);

  function aggregatedStatsAtTime(time) {
    const stats = {};
    const cache = events[categoryBreakdownCacheSymbol];

    if (!cache) {
      return stats;
    }
    for (const category of Object.keys(cache)) {
      const categoryCache = cache[category];
      const index = upperBound(categoryCache.time, time, (a, b) => a - b);
      let value;

      if (index === 0) {
        value = 0;
      } else if (index === categoryCache.time.length) {
        value = categoryCache.value[categoryCache.value.length - 1];
      } else {
        const t0 = categoryCache.time[index - 1];
        const t1 = categoryCache.time[index];
        const v0 = categoryCache.value[index - 1];
        const v1 = categoryCache.value[index];

        value = v0 + (v1 - v0) * (time - t0) / (t1 - t0);
      }
      stats[category] = value;
    }

    return stats;
  }

  function subtractStats(a, b) {
    const result = { ...a };

    for (const key of Object.keys(b)) {
      result[key] = (result[key] || 0) - b[key];
    }

    return result;
  }

  const aggregatedStats = subtractStats(aggregatedStatsAtTime(endTime), aggregatedStatsAtTime(startTime));
  const aggregatedTotal = Object.values(aggregatedStats).reduce((a, b) => a + b, 0);

  aggregatedStats.idle = Math.max(0, endTime - startTime - aggregatedTotal);

  return aggregatedStats;
}

// Find ALL CrRendererMain threads, return the one with the most events
function findMainRendererThread(events) {