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device_management.h File Reference
#include <memory>
#include <string>
#include <vector>
#include "gromacs/utility/basedefinitions.h"
#include "gromacs/utility/iserializer.h"
+ Include dependency graph for device_management.h:
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Description

Declares functions to manage GPU resources.

This has several implementations: one for each supported GPU platform, and a stub implementation if the build does not support GPUs.

Author
Anca Hamuraru anca@.nosp@m.stre.nosp@m.amcom.nosp@m.puti.nosp@m.ng.eu
Dimitrios Karkoulis dimit.nosp@m.ris..nosp@m.karko.nosp@m.ulis.nosp@m.@gmai.nosp@m.l.co.nosp@m.m
Teemu Virolainen teemu.nosp@m.@str.nosp@m.eamco.nosp@m.mput.nosp@m.ing.e.nosp@m.u
Mark Abraham mark..nosp@m.j.ab.nosp@m.raham.nosp@m.@gma.nosp@m.il.co.nosp@m.m
Szilárd Páll pall..nosp@m.szil.nosp@m.ard@g.nosp@m.mail.nosp@m..com
Artem Zhmurov zhmur.nosp@m.ov@g.nosp@m.mail..nosp@m.com

Classes

class  gmx::ArrayRef< typename >
 STL-like interface to a C array of T (or part of a std container of T). More...
 

Functions

void warnWhenDeviceNotTargeted (const gmx::MDLogger &mdlog, const DeviceInformation &deviceInfo)
 Warn to the logger when the detected device was not one of the targets selected at configure time for compilation. More...
 
bool canPerformDeviceDetection (std::string *errorMessage)
 Return whether GPUs can be detected. More...
 
bool isDeviceDetectionEnabled ()
 Return whether GPU detection is enabled. More...
 
bool isDeviceDetectionFunctional (std::string *errorMessage)
 Return whether GPU detection is functioning correctly. More...
 
DeviceVendor getDeviceVendor (const char *vendorName)
 Returns an DeviceVendor value corresponding to the input OpenCL vendor name. More...
 
int getDeviceComputeUnitFactor (const DeviceInformation &deviceInfo)
 Get the factor to divide the number of compute units by. More...
 
std::vector< std::unique_ptr
< DeviceInformation > > 
findDevices ()
 Find all GPUs in the system. More...
 
std::vector
< std::reference_wrapper
< DeviceInformation > > 
getCompatibleDevices (const std::vector< std::unique_ptr< DeviceInformation >> &deviceInfoList)
 Return a container of device-information handles that are compatible. More...
 
std::vector< int > getCompatibleDeviceIds (gmx::ArrayRef< const std::unique_ptr< DeviceInformation >> deviceInfoList)
 Return a container of the IDs of the compatible GPU ids. More...
 
bool deviceIdIsCompatible (gmx::ArrayRef< const std::unique_ptr< DeviceInformation >> deviceInfoList, int deviceId)
 Return whether deviceId is found in deviceInfoList and is compatible. More...
 
gmx::GpuAwareMpiStatus getMinimalSupportedGpuAwareMpiStatus (gmx::ArrayRef< const std::unique_ptr< DeviceInformation >> deviceInfoList)
 Return whether all compatible devices in deviceInfoList support GPU-aware MPI. More...
 
void setActiveDevice (const DeviceInformation &deviceInfo)
 Set the active GPU. More...
 
void releaseDevice (DeviceInformation *deviceInfo)
 Releases the GPU device used by the active context at the time of calling (CUDA only). More...
 
std::string getDeviceInformationString (const DeviceInformation &deviceInfo)
 Formats and returns a device information string for a given GPU. More...
 
std::string getDeviceCompatibilityDescription (gmx::ArrayRef< const std::unique_ptr< DeviceInformation >> deviceInfoList, int deviceId)
 Return a string describing how compatible the GPU with given deviceId is. More...
 
void serializeDeviceInformations (const std::vector< std::unique_ptr< DeviceInformation >> &deviceInfoList, gmx::ISerializer *serializer)
 Serialization of information on devices for MPI broadcasting. More...
 
std::vector< std::unique_ptr
< DeviceInformation > > 
deserializeDeviceInformations (gmx::ISerializer *serializer)
 Deserialization of information on devices after MPI broadcasting. More...
 

Function Documentation

bool canPerformDeviceDetection ( std::string *  errorMessage)

Return whether GPUs can be detected.

Returns true when this is a build of GROMACS configured to support GPU usage, GPU detection is not disabled by GMX_DISABLE_GPU_DETECTION environment variable and a valid device driver, ICD, and/or runtime was detected. Does not throw.

Parameters
[out]errorMessageWhen returning false on a build configured with GPU support and non-nullptr was passed, the string contains a descriptive message about why GPUs cannot be detected.
std::vector<std::unique_ptr<DeviceInformation> > deserializeDeviceInformations ( gmx::ISerializer serializer)

Deserialization of information on devices after MPI broadcasting.

Parameters
[in]serializerSerializing object.
Returns
deviceInfoList Deserialized vector with device informations.
bool deviceIdIsCompatible ( gmx::ArrayRef< const std::unique_ptr< DeviceInformation >>  deviceInfoList,
int  deviceId 
)

Return whether deviceId is found in deviceInfoList and is compatible.

This function filters the result of the detection for compatible GPUs, based on the previously run compatibility tests.

Parameters
[in]deviceInfoListAn information on available devices.
[in]deviceIdThe device ID to find in the list.
Exceptions
RangeErrorIf deviceId does not match the id of any device in deviceInfoList
Returns
Whether deviceId is compatible.
std::vector<std::unique_ptr<DeviceInformation> > findDevices ( )

Find all GPUs in the system.

Will detect every GPU supported by the device driver in use. Must only be called if canPerformDeviceDetection() has returned true. This routine also checks for the compatibility of each device and fill the deviceInfo array with the required information on each device: ID, device properties, status.

Note that this function leaves the GPU runtime API error state clean; this is implemented ATM in the CUDA flavor. This invalidates any existing CUDA streams, allocated memory on GPU, etc.

Todo:
: Check if errors do propagate in OpenCL as they do in CUDA and whether there is a mechanism to "clear" them.
Returns
Standard vector with the list of devices found
Exceptions
InternalErrorif a GPU API returns an unexpected failure (because the call to canDetectGpus() should always prevent this occuring)
std::vector<int> getCompatibleDeviceIds ( gmx::ArrayRef< const std::unique_ptr< DeviceInformation >>  deviceInfoList)

Return a container of the IDs of the compatible GPU ids.

This function filters the result of the detection for compatible GPUs, based on the previously run compatibility tests.

Parameters
[in]deviceInfoListAn information on available devices.
Returns
Vector of compatible GPU ids.
std::vector<std::reference_wrapper<DeviceInformation> > getCompatibleDevices ( const std::vector< std::unique_ptr< DeviceInformation >> &  deviceInfoList)

Return a container of device-information handles that are compatible.

This function filters the result of the detection for compatible GPUs, based on the previously run compatibility tests.

Parameters
[in]deviceInfoListAn information on available devices.
Returns
Vector of DeviceInformations on GPUs recorded as compatible
std::string getDeviceCompatibilityDescription ( gmx::ArrayRef< const std::unique_ptr< DeviceInformation >>  deviceInfoList,
int  deviceId 
)

Return a string describing how compatible the GPU with given deviceId is.

Parameters
[in]deviceInfoListAn information on available devices.
[in]deviceIdAn index of the device to check
Returns
A string describing the compatibility status, useful for error messages.
int getDeviceComputeUnitFactor ( const DeviceInformation deviceInfo)

Get the factor to divide the number of compute units by.

OpenCL and SYCL can report the number of Compute Units (CUs) a device has, see CL_DEVICE_MAX_COMPUTE_UNITS and info::device::max_compute_units. But "CU" is only vaguely defined by the standard, and on different vendors the same API call returns different things.

On NVIDIA, that is the number of SMs.

On AMD, that is the number of Compute Units, which are similar to CUDA's SM. Except on RDNA, where the number of Dual Compute Units is returned (https://stackoverflow.com/a/63976796/929437).

On Intel, that is the number of EUs (XVEs), which are similar to CUDA core. The concept similar to CUDA SM is called sub-slice (Xe Core, XC), and it contains 16 EUs (Gen9-Gen11, Xe).

This function uses CUDA SM as a reference. To get the number of SM-like units on a device, divide the result of CL_DEVICE_MAX_COMPUTE_UNITS / info::device::max_compute_units API call by the value returned by this function.

Todo:
: Handled AMD RDNA?
Parameters
[in]deviceInfoDevice information.
Returns
how many CUs are there in a single SM-like entity.
std::string getDeviceInformationString ( const DeviceInformation deviceInfo)

Formats and returns a device information string for a given GPU.

Given an index directly into the array of available GPUs, returns a formatted info string for the respective GPU which includes ID, name, compute capability, and detection status.

Parameters
[in]deviceInfoAn information on device that is to be set.
Returns
A string describing the device.
DeviceVendor getDeviceVendor ( const char *  vendorName)

Returns an DeviceVendor value corresponding to the input OpenCL vendor name.

Returns
DeviceVendor value for the input vendor name
gmx::GpuAwareMpiStatus getMinimalSupportedGpuAwareMpiStatus ( gmx::ArrayRef< const std::unique_ptr< DeviceInformation >>  deviceInfoList)

Return whether all compatible devices in deviceInfoList support GPU-aware MPI.

Returns
Whether all compatible devices in the list support GPU-aware MPI (both full support and forced support counts).
bool isDeviceDetectionEnabled ( )

Return whether GPU detection is enabled.

Returns true when this is a build of GROMACS configured to support GPU usage and GPU detection is not disabled by GMX_DISABLE_GPU_DETECTION environment variable.

Does not throw.

bool isDeviceDetectionFunctional ( std::string *  errorMessage)

Return whether GPU detection is functioning correctly.

Returns true when this is a build of GROMACS configured to support GPU usage, and a valid device driver, ICD, and/or runtime was detected.

This function is not intended to be called from build configurations that do not support GPUs, and there will be no descriptive message in that case.

Parameters
[out]errorMessageWhen returning false on a build configured with GPU support and non-nullptr was passed, the string contains a descriptive message about why GPUs cannot be detected.

Does not throw.

void releaseDevice ( DeviceInformation deviceInfo)

Releases the GPU device used by the active context at the time of calling (CUDA only).

If deviceInfo is nullptr, then it is understood that no device was selected so no context is active to be freed. Otherwise, the context is explicitly destroyed and therefore all data uploaded to the GPU is lost. This must only be called when none of this data is required anymore, because subsequent attempts to free memory associated with the context will otherwise fail.

Calls gmx_warning upon errors.

Todo:
This should go through all the devices, not only the one currently active. Reseting only one device will not work, e.g. in CUDA tests.
Parameters
[in]deviceInfoInformation on the device to be released.
void serializeDeviceInformations ( const std::vector< std::unique_ptr< DeviceInformation >> &  deviceInfoList,
gmx::ISerializer serializer 
)

Serialization of information on devices for MPI broadcasting.

Parameters
[in]deviceInfoListThe vector with device informations to serialize.
[in]serializerSerializing object.
void setActiveDevice ( const DeviceInformation deviceInfo)

Set the active GPU.

This sets the device for which the device information is passed active. Essential in CUDA, where the device buffers and kernel launches are not connected to the device context. In OpenCL, checks the device vendor and makes vendor-specific performance adjustments.

Parameters
[in]deviceInfoInformation on the device to be set.

Issues a fatal error for any critical errors that occur during initialization.

void warnWhenDeviceNotTargeted ( const gmx::MDLogger mdlog,
const DeviceInformation deviceInfo 
)

Warn to the logger when the detected device was not one of the targets selected at configure time for compilation.

Parameters
[in]mdlogLogger
[in]deviceInfoThe device to potentially warn about