gecko-dev/hal/HalTypes.h
Jamie Nicol 938068b316 Bug 1850573 - Add HeterogeneousCpuInfo to HAL with Android implementation. r=geckoview-reviewers,owlish
This adds a function GetHeterogeneousCpuInfo() to HAL, which
classifies the processor cores in to "big", "medium", and
"little". This is currently only implemented on Android, where it
works by parsing the maximum CPU frequency from sysfs.

When all CPUs have the same frequency they are all classified as
"big", and when there are only 2 different frequencies they are
classified as "big" and "little". All CPUs with a frequency in-between
the lowest and highest are classified as "medium".

This information can be used to count the number of each cores in each
category, eg for determining appropriate thread pool sizes. Or to
determine the indices of cores in a certain category, eg for setting
CPU affinity for certain threads.

Differential Revision: https://phabricator.services.mozilla.com/D188478
2023-09-26 12:55:37 +00:00

130 lines
4.3 KiB
C++

/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* 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 http://mozilla.org/MPL/2.0/. */
#ifndef mozilla_hal_Types_h
#define mozilla_hal_Types_h
#include "ipc/EnumSerializer.h"
#include "mozilla/BitSet.h"
#include "mozilla/Observer.h"
#include "mozilla/TimeStamp.h"
#include "mozilla/UniquePtr.h"
namespace mozilla {
namespace hal {
/**
* These constants specify special values for content process IDs. You can get
* a content process ID by calling ContentChild::GetID() or
* ContentParent::GetChildID().
*/
const uint64_t CONTENT_PROCESS_ID_UNKNOWN = uint64_t(-1);
const uint64_t CONTENT_PROCESS_ID_MAIN = 0;
// Note that we rely on the order of this enum's entries. Higher priorities
// should have larger int values.
enum ProcessPriority {
PROCESS_PRIORITY_UNKNOWN = -1,
PROCESS_PRIORITY_BACKGROUND,
PROCESS_PRIORITY_BACKGROUND_PERCEIVABLE,
PROCESS_PRIORITY_FOREGROUND_KEYBOARD,
// The special class for the preallocated process, high memory priority but
// low CPU priority.
PROCESS_PRIORITY_PREALLOC,
// Any priority greater than or equal to FOREGROUND is considered
// "foreground" for the purposes of priority testing, for example
// CurrentProcessIsForeground().
PROCESS_PRIORITY_FOREGROUND,
PROCESS_PRIORITY_FOREGROUND_HIGH,
PROCESS_PRIORITY_PARENT_PROCESS,
NUM_PROCESS_PRIORITY
};
/**
* Convert a ProcessPriority enum value to a string. The strings returned by
* this function are statically allocated; do not attempt to free one!
*
* If you pass an unknown process priority, we fatally assert in debug
* builds and otherwise return "???".
*/
const char* ProcessPriorityToString(ProcessPriority aPriority);
/**
* Used by ModifyWakeLock
*/
enum WakeLockControl {
WAKE_LOCK_REMOVE_ONE = -1,
WAKE_LOCK_NO_CHANGE = 0,
WAKE_LOCK_ADD_ONE = 1,
NUM_WAKE_LOCK
};
/**
* Represents a workload shared by a group of threads that should be completed
* in a target duration each cycle.
*
* This is created using hal::CreatePerformanceHintSession(). Each cycle, the
* actual work duration should be reported using ReportActualWorkDuration(). The
* system can then adjust the scheduling accordingly in order to achieve the
* target.
*/
class PerformanceHintSession {
public:
virtual ~PerformanceHintSession() = default;
// Updates the session's target work duration for each cycle.
virtual void UpdateTargetWorkDuration(TimeDuration aDuration) = 0;
// Reports the session's actual work duration for a cycle.
virtual void ReportActualWorkDuration(TimeDuration aDuration) = 0;
};
/**
* Categorizes the CPUs on the system in to big, medium, and little classes.
*
* A set bit in each bitset indicates that the CPU of that index belongs to that
* class. If the CPUs are fully homogeneous they are all categorized as big. If
* there are only 2 classes, they are categorized as either big or little.
* Finally, if there are >= 3 classes, the remainder will be categorized as
* medium.
*
* If there are more than MAX_CPUS present we are unable to represent this
* information.
*/
struct HeterogeneousCpuInfo {
// We use a max of 32 because currently this is only implemented for Android
// where we are unlikely to need more CPUs than that, and it simplifies
// dealing with cpu_set_t as CPU_SETSIZE is 32 on 32-bit Android.
static const size_t MAX_CPUS = 32;
size_t mTotalNumCpus;
mozilla::BitSet<MAX_CPUS> mLittleCpus;
mozilla::BitSet<MAX_CPUS> mMediumCpus;
mozilla::BitSet<MAX_CPUS> mBigCpus;
};
} // namespace hal
} // namespace mozilla
namespace IPC {
/**
* WakeLockControl serializer.
*/
template <>
struct ParamTraits<mozilla::hal::WakeLockControl>
: public ContiguousEnumSerializer<mozilla::hal::WakeLockControl,
mozilla::hal::WAKE_LOCK_REMOVE_ONE,
mozilla::hal::NUM_WAKE_LOCK> {};
template <>
struct ParamTraits<mozilla::hal::ProcessPriority>
: public ContiguousEnumSerializer<mozilla::hal::ProcessPriority,
mozilla::hal::PROCESS_PRIORITY_UNKNOWN,
mozilla::hal::NUM_PROCESS_PRIORITY> {};
} // namespace IPC
#endif // mozilla_hal_Types_h