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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 "HalTypes.h"
#include "nsTArray.h"
#include <windows.h>
namespace mozilla::hal_impl {
static mozilla::Maybe<hal::HeterogeneousCpuInfo> CreateHeterogeneousCpuInfo() {
ULONG returnedLength;
GetSystemCpuSetInformation(NULL, 0, &returnedLength, NULL, 0);
if (!returnedLength) {
return Nothing();
}
AutoTArray<uint8_t, 1024> cpuSets;
cpuSets.SetLength(returnedLength);
if (!GetSystemCpuSetInformation(
reinterpret_cast<SYSTEM_CPU_SET_INFORMATION*>(cpuSets.Elements()),
returnedLength, &returnedLength, NULL, 0)) {
return Nothing();
}
hal::HeterogeneousCpuInfo info;
info.mTotalNumCpus = 0;
BYTE maxEfficiencyClass = 0;
BYTE minEfficiencyClass = UINT8_MAX;
size_t currentPosition = 0;
while (currentPosition < returnedLength) {
SYSTEM_CPU_SET_INFORMATION& set =
*reinterpret_cast<SYSTEM_CPU_SET_INFORMATION*>(cpuSets.Elements() +
currentPosition);
currentPosition += set.Size;
if (currentPosition > returnedLength) {
MOZ_ASSERT(false);
return Nothing();
}
if (set.Type != CpuSetInformation || !set.CpuSet.Id) {
continue;
}
info.mTotalNumCpus += 1;
maxEfficiencyClass =
std::max(maxEfficiencyClass, set.CpuSet.EfficiencyClass);
minEfficiencyClass =
std::min(minEfficiencyClass, set.CpuSet.EfficiencyClass);
}
if (!info.mTotalNumCpus) {
// This is weird.
return Nothing();
}
currentPosition = 0;
size_t currentCPU = 0;
// The API has currently a limit how many cpu cores it can tell about.
while (currentPosition < returnedLength) {
if (currentCPU >= 32) {
break;
}
SYSTEM_CPU_SET_INFORMATION& set =
*reinterpret_cast<SYSTEM_CPU_SET_INFORMATION*>(cpuSets.Elements() +
currentPosition);
currentPosition += set.Size;
// If this happens the code above should already have bailed.
MOZ_ASSERT(currentPosition <= returnedLength);
// EfficiencyClass doesn't obviously translate to our model, for now what
// we are doing is counting everything of 'max' power use as a big core,
// everything of 'min' power use as a little code, and everything else as
// medium.
if (set.CpuSet.EfficiencyClass == maxEfficiencyClass) {
info.mBigCpus[currentCPU++] = true;
} else if (set.CpuSet.EfficiencyClass == minEfficiencyClass) {
info.mLittleCpus[currentCPU++] = true;
} else {
info.mMediumCpus[currentCPU++] = true;
}
}
return Some(info);
}
const Maybe<hal::HeterogeneousCpuInfo>& GetHeterogeneousCpuInfo() {
static const Maybe<hal::HeterogeneousCpuInfo> cpuInfo =
CreateHeterogeneousCpuInfo();
return cpuInfo;
}
} // namespace mozilla::hal_impl
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