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// 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/startup_helper.h"
#include <algorithm>
#include <memory>
#include <set>
#include <string>
#include "base/base_switches.h"
#include "base/command_line.h"
#include "base/metrics/field_trial_params.h"
#include "base/system/sys_info.h"
#include "base/task/thread_pool/initialization_util.h"
#include "base/task/thread_pool/thread_pool_instance.h"
#include "build/build_config.h"
#include "content/common/thread_pool_util.h"
#include "content/public/common/content_switch_dependent_feature_overrides.h"
#include "content/public/common/content_switches.h"
namespace content {
std::unique_ptr<base::FieldTrialList> SetUpFieldTrialsAndFeatureList() {
std::unique_ptr<base::FieldTrialList> field_trial_list;
if (!base::FieldTrialList::GetInstance())
field_trial_list = std::make_unique<base::FieldTrialList>(nullptr);
const base::CommandLine* command_line =
base::CommandLine::ForCurrentProcess();
// Ensure any field trials specified on the command line are initialized.
if (command_line->HasSwitch(::switches::kForceFieldTrials)) {
// Create field trials without activating them, so that this behaves in a
// consistent manner with field trials created from the server.
bool result = base::FieldTrialList::CreateTrialsFromString(
command_line->GetSwitchValueASCII(::switches::kForceFieldTrials));
CHECK(result) << "Invalid --" << ::switches::kForceFieldTrials
<< " list specified.";
}
base::FeatureList::InitializeInstance(
command_line->GetSwitchValueASCII(switches::kEnableFeatures),
command_line->GetSwitchValueASCII(switches::kDisableFeatures),
GetSwitchDependentFeatureOverrides(*command_line));
return field_trial_list;
}
namespace {
#if defined(OS_ANDROID)
// Mobile config, for iOS see ios/web/app/web_main_loop.cc.
constexpr int kThreadPoolDefaultMin = 6;
constexpr int kThreadPoolMax = 8;
constexpr double kThreadPoolCoresMultiplier = 0.6;
constexpr int kThreadPoolOffset = 0;
#else
// Desktop config.
constexpr int kThreadPoolDefaultMin = 16;
constexpr int kThreadPoolMax = 32;
constexpr double kThreadPoolCoresMultiplier = 0.6;
constexpr int kThreadPoolOffset = 0;
#endif
const base::Feature kBrowserThreadPoolAdjustment{
"BrowserThreadPoolAdjustment", base::FEATURE_DISABLED_BY_DEFAULT};
const base::FeatureParam<int> kBrowserThreadPoolMin{
&kBrowserThreadPoolAdjustment, "min", kThreadPoolDefaultMin};
} // namespace
// TODO(scheduler-dev): Standardize thread pool logic and remove the need for
// specifying thread count manually.
void StartBrowserThreadPool() {
// Ensure we always support at least one thread regardless of the field trial
// param setting.
int min = std::max(kBrowserThreadPoolMin.Get(), 1);
base::ThreadPoolInstance::InitParams thread_pool_init_params = {
base::RecommendedMaxNumberOfThreadsInThreadGroup(
min, kThreadPoolMax, kThreadPoolCoresMultiplier, kThreadPoolOffset)};
#if defined(OS_WIN)
thread_pool_init_params.common_thread_pool_environment = base::
ThreadPoolInstance::InitParams::CommonThreadPoolEnvironment::COM_MTA;
#endif
// If a renderer lives in the browser process, adjust the number of
// threads in the foreground pool.
if (base::CommandLine::ForCurrentProcess()->HasSwitch(
switches::kSingleProcess)) {
thread_pool_init_params.max_num_foreground_threads =
std::max(GetMinForegroundThreadsInRendererThreadPool(),
thread_pool_init_params.max_num_foreground_threads);
}
base::ThreadPoolInstance::Get()->Start(thread_pool_init_params);
}
} // namespace content
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