chrome/browser/performance_monitor/metric.cc

   1 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 #include "chrome/browser/performance_monitor/metric.h"
   6
   7 #include "base/basictypes.h"
   8 #include "base/logging.h"
   9 #include "base/strings/string_number_conversions.h"
  10 #include "base/time/time.h"
  11 #include "chrome/browser/performance_monitor/constants.h"
  12
  13 namespace performance_monitor {
  14
  15 namespace {
  16
  17 // For certain metrics (for instance, bytes read), it is possible that there is
  18 // no maximum value which we can safely assume.
  19 const double kNoMaximum = -1.0;
  20
  21 // These constants are designed to keep metrics reasonable. However, due to the
  22 // variety of system configurations which can run chrome, these values may not
  23 // catch *all* erroneous values. For instance, on a one-CPU machine, any CPU
  24 // usage > 100 is erroneous, but on a 16-CPU machine, it's perfectly normal.
  25 // These are "best-guesses" in order to weed out obviously-false values. A
  26 // metric is valid if it is greater than or equal to the minimum and less than
  27 // the maximum, i.e. if it falls in the range [min, max).
  28 const double kMinUndefined = 0.0;
  29 const double kMaxUndefined = 0.0;  // No undefined metric is valid.
  30 const double kMinCpuUsage = 0.0;
  31 const double kMaxCpuUsage = 100000.0;  // 100% on a 1000-CPU machine.
  32 const double kMinPrivateMemoryUsage = 0.0;
  33 const double kMaxPrivateMemoryUsage = kBytesPerTerabyte;
  34 const double kMinSharedMemoryUsage = 0.0;
  35 const double kMaxSharedMemoryUsage = kBytesPerTerabyte;
  36 const double kMinStartupTime = 0.0;
  37 const double kMaxStartupTime = base::Time::kMicrosecondsPerMinute * 15.0;
  38 const double kMinTestStartupTime = 0.0;
  39 const double kMaxTestStartupTime = base::Time::kMicrosecondsPerMinute * 15.0;
  40 const double kMinSessionRestoreTime = 0.0;
  41 const double kMaxSessionRestoreTime = base::Time::kMicrosecondsPerMinute * 15.0;
  42 const double kMinPageLoadTime = 0.0;
  43 const double kMaxPageLoadTime = base::Time::kMicrosecondsPerMinute * 15.0;
  44 const double kMinNetworkBytesRead = 0.0;
  45 const double kMaxNetworkBytesRead = kNoMaximum;
  46
  47 struct MetricBound {
  48   double min;
  49   double max;
  50 };
  51
  52 const MetricBound kMetricBounds[] = {
  53  { kMinUndefined, kMaxUndefined },
  54  { kMinCpuUsage, kMaxCpuUsage },
  55  { kMinPrivateMemoryUsage, kMaxPrivateMemoryUsage },
  56  { kMinSharedMemoryUsage, kMaxSharedMemoryUsage },
  57  { kMinStartupTime, kMaxStartupTime },
  58  { kMinTestStartupTime, kMaxTestStartupTime },
  59  { kMinSessionRestoreTime, kMaxSessionRestoreTime },
  60  { kMinPageLoadTime, kMaxPageLoadTime },
  61  { kMinNetworkBytesRead, kMaxNetworkBytesRead },
  62 };
  63
  64 COMPILE_ASSERT(ARRAYSIZE_UNSAFE(kMetricBounds) == METRIC_NUMBER_OF_METRICS,
  65                metric_bounds_size_doesnt_match_metric_count);
  66
  67 }  // namespace
  68
  69 Metric::Metric() : type(METRIC_UNDEFINED), value(0.0) {
  70 }
  71
  72 Metric::Metric(MetricType metric_type,
  73                const base::Time& metric_time,
  74                const double metric_value)
  75     : type(metric_type), time(metric_time), value(metric_value) {
  76 }
  77
  78 Metric::Metric(MetricType metric_type,
  79                const std::string& metric_time,
  80                const std::string& metric_value) : type(metric_type) {
  81   int64 conversion = 0;
  82   base::StringToInt64(metric_time, &conversion);
  83   time = base::Time::FromInternalValue(conversion);
  84   CHECK(base::StringToDouble(metric_value, &value));
  85 }
  86
  87 Metric::~Metric() {
  88 }
  89
  90 bool Metric::IsValid() const {
  91   return type < METRIC_NUMBER_OF_METRICS &&
  92       (value < kMetricBounds[type].max ||
  93           kMetricBounds[type].max == kNoMaximum) &&
  94       value >= kMetricBounds[type].min;
  95 }
  96
  97 std::string Metric::ValueAsString() const {
  98   return base::DoubleToString(value);
  99 }
 100
 101 }  // namespace performance_monitor