blob: f37a7c23ff5f739137cfb7a89d2f9a286092e6b0 [file] [log] [blame]
// Copyright 2018 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#include "components/live_tab_count_metrics/live_tab_count_metrics.h"
#include <limits>
#include "base/logging.h"
#include "base/stl_util.h"
namespace live_tab_count_metrics {
// These values represent the lower bound for each bucket, and define the live
// tab count buckets. The final bucket has no upper bound, and each other
// bucket, i, is bounded above by the lower bound of bucket i + 1.
// The buckets were determined from the Tabs.MaxTabsInADay histogram,
// approximating the 25th, 50th, 75th, 95th, and 99th percentiles, but with the
// single and zero tab cases separated.
// If adding or removing a bucket, update |kNumLiveTabCountBuckets|,
// |kLiveTabCountBucketMins|, and |kLiveTabCountBucketNames|. If adding,
// removing, or changing bucket ranges, the existing metrics that use these
// functions for emitting histograms should be marked as obsolete, and new
// metrics should be created. This can be accomplished by versioning
// |kLiveTabCountBucketNames|, e.g. ".ByLiveTabCount2.0Tabs", etc., and
// updating the histogram suffixes section of histograms.xml, creating a new
// entry for the new suffixes and marking the old suffixes obsolete.
constexpr size_t kLiveTabCountBucketMins[] = {0, 1, 2, 3, 5, 8, 20, 40};
// Text for the live tab count portion of metric names. These need to be kept
// in sync with |kLiveTabCountBucketMins|.
constexpr const char* kLiveTabCountBucketNames[]{
".ByLiveTabCount.0Tabs", ".ByLiveTabCount.1Tab",
".ByLiveTabCount.2Tabs", ".ByLiveTabCount.3To4Tabs",
".ByLiveTabCount.5To7Tabs", ".ByLiveTabCount.8To19Tabs",
".ByLiveTabCount.20To39Tabs", ".ByLiveTabCount.40OrMoreTabs"};
std::string HistogramName(const std::string prefix, size_t bucket) {
base::size(kLiveTabCountBucketMins) == kNumLiveTabCountBuckets,
"kLiveTabCountBucketMins must have kNumLiveTabCountBuckets elements.");
base::size(kLiveTabCountBucketNames) == kNumLiveTabCountBuckets,
"kLiveTabCountBucketNames must have kNumLiveTabCountBuckets elements.");
DCHECK_LT(bucket, kNumLiveTabCountBuckets);
return prefix + kLiveTabCountBucketNames[bucket];
size_t BucketForLiveTabCount(size_t num_live_tabs) {
for (size_t bucket = 0; bucket < kNumLiveTabCountBuckets; bucket++) {
if (internal::IsInBucket(num_live_tabs, bucket))
return bucket;
// There should be a bucket for any number of tabs >= 0.
return kNumLiveTabCountBuckets;
namespace internal {
size_t BucketMin(size_t bucket) {
DCHECK_LT(bucket, kNumLiveTabCountBuckets);
return kLiveTabCountBucketMins[bucket];
size_t BucketMax(size_t bucket) {
DCHECK_LT(bucket, kNumLiveTabCountBuckets);
// The last bucket includes everything after the min bucket value.
if (bucket == kNumLiveTabCountBuckets - 1)
return std::numeric_limits<size_t>::max();
return kLiveTabCountBucketMins[bucket + 1] - 1;
bool IsInBucket(size_t num_live_tabs, size_t bucket) {
DCHECK_LT(bucket, kNumLiveTabCountBuckets);
return num_live_tabs >= BucketMin(bucket) &&
num_live_tabs <= BucketMax(bucket);
} // namespace internal
} // namespace live_tab_count_metrics