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/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* vim: set ts=8 sts=2 et sw=2 tw=80: */
/* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at https://mozilla.org/MPL/2.0/. */
#include "Hal.h"
#include "HalLog.h"
#include "HalTypes.h"
#include "mozilla/BitSet.h"
#include "mozilla/CheckedInt.h"
#include "prsystem.h"
#include <fstream>
namespace mozilla::hal_impl {
mozilla::Maybe<HeterogeneousCpuInfo> CreateHeterogeneousCpuInfo() {
CheckedInt<size_t> cpuCount = PR_GetNumberOfProcessors();
if (!cpuCount.isValid()) {
HAL_ERR("HeterogeneousCpuInfo: Failed to query processor count");
return Nothing();
}
if (cpuCount.value() > HeterogeneousCpuInfo::MAX_CPUS) {
HAL_ERR("HeterogeneousCpuInfo: Too many cpus");
return Nothing();
}
std::vector<std::pair<int, int>> cpu_freqs;
cpu_freqs.reserve(cpuCount.value());
for (size_t i = 0; i < cpuCount.value(); i++) {
std::stringstream freq_filename;
// On all devices tested, even with isolated content processes we do have
// permission to read this file. If, however, this function stops working
// one day, then this may be a good place to start investigating.
freq_filename << "/sys/devices/system/cpu/cpu" << i
<< "/cpufreq/cpuinfo_max_freq";
std::ifstream ifs(freq_filename.str());
if (!ifs) {
HAL_ERR("HeterogeneousCpuInfo: Failed to open file %s",
freq_filename.str().c_str());
return Nothing();
}
int freq;
if (!(ifs >> freq)) {
HAL_ERR("HeterogeneousCpuInfo: Failed to parse file %s",
freq_filename.str().c_str());
return Nothing();
}
cpu_freqs.push_back(std::make_pair(i, freq));
}
std::sort(cpu_freqs.begin(), cpu_freqs.end(),
[](auto lhs, auto rhs) { return lhs.second < rhs.second; });
HeterogeneousCpuInfo info;
info.mTotalNumCpus = cpuCount.value();
int lowest_freq = cpu_freqs.front().second;
int highest_freq = cpu_freqs.back().second;
for (const auto& [cpu, freq] : cpu_freqs) {
if (freq == highest_freq) {
info.mBigCpus[cpu] = true;
} else if (freq == lowest_freq) {
info.mLittleCpus[cpu] = true;
} else {
info.mMediumCpus[cpu] = true;
}
}
HAL_LOG("HeterogeneousCpuInfo: little: %zu, med: %zu, big: %zu",
info.mLittleCpus.Count(), info.mMediumCpus.Count(),
info.mBigCpus.Count());
return Some(info);
}
const Maybe<HeterogeneousCpuInfo>& GetHeterogeneousCpuInfo() {
static const Maybe<HeterogeneousCpuInfo> cpuInfo =
CreateHeterogeneousCpuInfo();
return cpuInfo;
}
} // namespace mozilla::hal_impl
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