blob: 605c3f2cac82205b536a480767d4a28281d97c02 [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 "content/browser/web_package/signed_exchange_prefetch_metric_recorder.h"
#include "base/metrics/histogram_macros.h"
#include "base/time/tick_clock.h"
namespace content {
constexpr size_t kMaxEntries = 256u;
// SignedExchangePrefetchMetricRecorder will not associate prefetch
// to a navigation if they are older than |kPrefetchExpireTimeDelta|.
constexpr base::TimeDelta kPrefetchExpireTimeDelta =
base::TimeDelta::FromMilliseconds(30000);
// SignedExchangePrefetchMetricRecorder flushes expired prefetch entries once
// per |kFlushTimeoutTimeDelta|.
constexpr base::TimeDelta kFlushTimeoutTimeDelta =
base::TimeDelta::FromMilliseconds(30100);
constexpr char kPrecisionHistogram[] =
"SignedExchange.Prefetch.Precision.30Seconds";
constexpr char kRecallHistogram[] = "SignedExchange.Prefetch.Recall.30Seconds";
SignedExchangePrefetchMetricRecorder::SignedExchangePrefetchMetricRecorder(
const base::TickClock* tick_clock)
: tick_clock_(tick_clock),
flush_timer_(std::make_unique<base::OneShotTimer>(tick_clock)) {
DETACH_FROM_SEQUENCE(sequence_checker_);
}
SignedExchangePrefetchMetricRecorder::~SignedExchangePrefetchMetricRecorder() =
default;
void SignedExchangePrefetchMetricRecorder::OnSignedExchangePrefetchFinished(
const GURL& outer_url,
base::Time response_time) {
DCHECK_CALLED_ON_VALID_SEQUENCE(sequence_checker_);
if (disabled_)
return;
if (recent_prefetch_entries_.size() > kMaxEntries) {
// Avoid DoS. Turn off further metric logging to avoid skew too.
recent_prefetch_entries_.clear();
disabled_ = true;
return;
}
// Update |prefetch_time| for an existing entry.
recent_prefetch_entries_.insert_or_assign(
std::make_pair(outer_url, response_time), tick_clock_->NowTicks());
if (!flush_timer_->IsRunning())
ScheduleFlushTimer();
}
void SignedExchangePrefetchMetricRecorder::OnSignedExchangeNonPrefetch(
const GURL& outer_url,
base::Time response_time) {
DCHECK_CALLED_ON_VALID_SEQUENCE(sequence_checker_);
if (disabled_)
return;
auto it =
recent_prefetch_entries_.find(std::make_pair(outer_url, response_time));
bool prefetch_found = false;
if (it != recent_prefetch_entries_.end()) {
prefetch_found = true;
recent_prefetch_entries_.erase(it);
}
UMA_HISTOGRAM_BOOLEAN(kRecallHistogram, prefetch_found);
if (prefetch_found)
UMA_HISTOGRAM_BOOLEAN(kPrecisionHistogram, true);
}
void SignedExchangePrefetchMetricRecorder::ScheduleFlushTimer() {
DCHECK_CALLED_ON_VALID_SEQUENCE(sequence_checker_);
flush_timer_->Start(
FROM_HERE, kFlushTimeoutTimeDelta,
base::BindOnce(&SignedExchangePrefetchMetricRecorder::OnFlushTimer,
base::Unretained(this)));
}
void SignedExchangePrefetchMetricRecorder::OnFlushTimer() {
DCHECK_CALLED_ON_VALID_SEQUENCE(sequence_checker_);
if (disabled_)
return;
const base::TimeTicks expire_before =
tick_clock_->NowTicks() - kPrefetchExpireTimeDelta;
PrefetchEntries entries;
std::swap(entries, recent_prefetch_entries_);
for (const auto& it : entries) {
const base::TimeTicks prefetch_time = it.second;
if (prefetch_time < expire_before) {
UMA_HISTOGRAM_BOOLEAN(kPrecisionHistogram, false);
continue;
}
recent_prefetch_entries_.insert(it);
}
if (!recent_prefetch_entries_.empty())
ScheduleFlushTimer();
}
} // namespace content