| Note |
|---|
In progress… |
https://github.com/pytorch/cpuinfo#cpu-information-library
| Table of Contents | ||||||
|---|---|---|---|---|---|---|
|
Information is needed by cpu info
Concept
Data representation
Information is available through MSDN API
Concept
Data representation
Background:
https://docs.microsoft.com/en-us/windows/win32/procthread/processor-groups
Logical processor
one logical computing engine from the perspective of the operating system, application or driver
Core
one processor unit, which can consist of one or more logical processors
Physical processor
A physical processor is the same as a processor package, a socket, or a CPU.
can consist of one or more cores
Concerns
Cluster as a missing entity on x86 (respectively on Windows)
Current implementations of x86 Windows and MacOS set cluster count (per package) to fixed 1.
CPU Info fills 3 container layers (package, cluster, core), but queries only 2:
RelationProcessorPackageRelationProcessorCore
Cluster on Arm-Linux, the cluster count is detected
The higher level of ProcessorPackage in MSDN API is ProcessorGroup, but (looks like) it’s not equal to cluster.
cpuinfo reporting demo tool doesn’t report the number of clusters: https://github.com/pytorch/cpuinfo/blob/master/tools/cpu-info.c
Missing topology APIs for Arm on Windows
Get vendor and SoC name
Registry
| Code Block |
|---|
PS C:\kg\python_test\github_packages\cpuinfo> reg query HKLM\Hardware\Description\System\CentralProcessor\0 /v ProcessorNameString
HKEY_LOCAL_MACHINE\Hardware\Description\System\CentralProcessor\0
ProcessorNameString REG_SZ Microsoft SQ2 @ 3.15 GHz |
wmic
It reads information about the currently used core only, no direct connection with system logical information reported processors.
https://docs.microsoft.com/en-us/windows/win32/wmisdk/example-creating-a-wmi-application
| Code Block |
|---|
wmic cpu list /format:list AddressWidth=64 Architecture=12 Availability=3 Caption=ARMv8 (64-bit) Family 8 Model 805 Revision D0E ConfigManagerErrorCode= ConfigManagerUserConfig= CpuStatus=1 CreationClassName=Win32_Processor CurrentClockSpeed=3148 CurrentVoltage=11 DataWidth=64 Description=ARMv8 (64-bit) Family 8 Model 805 Revision D0E DeviceID=CPU0 ErrorCleared= ErrorDescription= ExtClock= Family=280 InstallDate= L2CacheSize=1280 L2CacheSpeed= LastErrorCode= Level=2053 LoadPercentage=7 Manufacturer=Qualcomm Technologies Inc MaxClockSpeed=3148 Name=Microsoft SQ2 @ 3.15 GHz OtherFamilyDescription= PNPDeviceID= PowerManagementCapabilities= PowerManagementSupported=FALSE ProcessorId=0000000000000000 ProcessorType=3 Revision=3342 Role=CPU SocketDesignation=Qualcomm Status=OK StatusInfo=3 Stepping=14 SystemCreationClassName=Win32_ComputerSystem SystemName=040644303253 UniqueId= UpgradeMethod=6 Version=Model 13, Stepping 14 VoltageCaps= |
Read MIDR
Not available in userspace in WoA
https://developer.arm.com/documentation/ddi0595/2021-06/AArch64-Registers/MIDR-EL1--Main-ID-Register
Get processor type per core
GetSystemInformation works on running corereports information on the currently used core only, so not system wide and no direct connection with system logical information reported processors.
big - little topology per core: uarch in cpuinfo
EfficiencyClass can mean bigger numbers are big cores while the rest are little cores , but doesn’t guaranteecurrently. In the future it can be changed.
PROCESSOR_RELATIONSHIP (winnt.h) - Win32 apps | Microsoft Docs
Get Cache Partitions and Set
Cpuinfo would need cache partitions and sets, while these are not reported by https://docs.microsoft.com/en-us/windows/win32/api/winnt/ns-winnt-cache_relationship
https://github.com/pytorch/cpuinfo/blob/master/include/cpuinfo.h#L101