我们有一些夜间构建机器安装了cuda libraries但没有安装cuda的GPU。这些机器能够构建启用cuda的程序，但它们无法运行这些程序。
在我们的自动夜间构建过程中，我们的cmake脚本使用cmake命令
find_package(CUDA)
确定是否安装了cuda软件。这会在安装了cuda软件的平台上设置cmake变量CUDA_FOUND。这很棒，而且效果很好。设置CUDA_FOUND后，可以构建启用cuda的程序。即使机器没有cuda功能的GPU。
但是，使用cuda的测试程序自然会在非GPU cuda机器上失败，导致我们的夜间仪表板看起来“脏”。所以我希望cmake避免在这样的机器上运行这些测试。但我仍然想在这些机器上构建cuda软件。
获得肯定的CUDA_FOUND结果后，我想测试是否存在实际的GPU，然后设置一个变量，比如CUDA_GPU_FOUND，以反映这一点。
让cmake测试是否存在具有cuda功能的gpu的最简单方法是什么？
这需要在三个平台上运行：Windows与MSVC，Mac和Linux。 （这就是我们首先使用cmake的原因）
编辑：在编写程序以测试GPU存在的答案中，有几个很好看的建议。仍然缺少的是让CMake在配置时编译和运行该程序的方法。我怀疑CMake中的TRY_RUN命令在这里很关键，但遗憾的是命令是nearly undocumented，我无法弄清楚如何使其工作。这个问题的CMake部分可能是一个更加困难的问题。也许我应该将此问为两个单独的问题......
答案 0 :(得分：18)
这个问题的答案由两部分组成：
对于第1部分，gpu嗅探程序，我从fabrizioM提供的答案开始，因为它非常紧凑。我很快发现，我需要在未知的答案中找到许多细节，以使其运作良好。我最终得到的是以下C源文件，我将其命名为has_cuda_gpu.c：
#include <stdio.h>
#include <cuda_runtime.h>
int main() {
int deviceCount, device;
int gpuDeviceCount = 0;
struct cudaDeviceProp properties;
cudaError_t cudaResultCode = cudaGetDeviceCount(&deviceCount);
if (cudaResultCode != cudaSuccess)
deviceCount = 0;
/* machines with no GPUs can still report one emulation device */
for (device = 0; device < deviceCount; ++device) {
cudaGetDeviceProperties(&properties, device);
if (properties.major != 9999) /* 9999 means emulation only */
++gpuDeviceCount;
}
printf("%d GPU CUDA device(s) found\n", gpuDeviceCount);
/* don't just return the number of gpus, because other runtime cuda
errors can also yield non-zero return values */
if (gpuDeviceCount > 0)
return 0; /* success */
else
return 1; /* failure */
}
请注意，在找到启用cuda的GPU的情况下，返回码为零。这是因为在我的一台us-cuda-but-no-GPU机器上，该程序会产生一个非零退出代码的运行时错误。所以任何非零退出代码都被解释为“cuda在这台机器上不起作用”。
你可能会问我为什么不在非GPU机器上使用cuda仿真模式。这是因为仿真模式是错误的。我只想调试我的代码，并解决cuda GPU代码中的错误。我没有时间调试模拟器。
问题的第二部分是使用此测试程序的cmake代码。经过一番努力，我已经弄明白了。以下块是较大CMakeLists.txt文件的一部分：
find_package(CUDA)
if(CUDA_FOUND)
try_run(RUN_RESULT_VAR COMPILE_RESULT_VAR
${CMAKE_BINARY_DIR}
${CMAKE_CURRENT_SOURCE_DIR}/has_cuda_gpu.c
CMAKE_FLAGS
-DINCLUDE_DIRECTORIES:STRING=${CUDA_TOOLKIT_INCLUDE}
-DLINK_LIBRARIES:STRING=${CUDA_CUDART_LIBRARY}
COMPILE_OUTPUT_VARIABLE COMPILE_OUTPUT_VAR
RUN_OUTPUT_VARIABLE RUN_OUTPUT_VAR)
message("${RUN_OUTPUT_VAR}") # Display number of GPUs found
# COMPILE_RESULT_VAR is TRUE when compile succeeds
# RUN_RESULT_VAR is zero when a GPU is found
if(COMPILE_RESULT_VAR AND NOT RUN_RESULT_VAR)
set(CUDA_HAVE_GPU TRUE CACHE BOOL "Whether CUDA-capable GPU is present")
else()
set(CUDA_HAVE_GPU FALSE CACHE BOOL "Whether CUDA-capable GPU is present")
endif()
endif(CUDA_FOUND)
这在cmake中设置一个CUDA_HAVE_GPU布尔变量，随后可用于触发条件操作。
我花了很长时间才弄清楚include和link参数需要放在CMAKE_FLAGS节中，以及语法应该是什么。 try_run documentation非常轻，但try_compile documentation中有更多信息，这是一个密切相关的命令。我仍然需要在网上搜索try_compile和try_run的示例，然后再开始工作。
另一个棘手但重要的细节是try_run的第三个参数，即“bindir”。您可能应该始终将其设置为${CMAKE_BINARY_DIR}。特别是，如果您位于项目的子目录中，请不要将其设置为${CMAKE_CURRENT_BINARY_DIR}。 CMake希望在bindir中找到子目录CMakeFiles/CMakeTmp，并在该目录不存在时发出错误。只需使用${CMAKE_BINARY_DIR}，这是这些子目录似乎自然存在的位置。
答案 1 :(得分：8)
写一个像
这样的简单程序#include<cuda.h>
int main (){
int deviceCount;
cudaError_t e = cudaGetDeviceCount(&deviceCount);
return e == cudaSuccess ? deviceCount : -1;
}
并检查返回值。
答案 2 :(得分：4)
我刚刚编写了一个纯Python脚本，它可以完成您需要的一些事情（我从pystream项目中获取了大部分内容）。它基本上只是CUDA运行时库中某些函数的包装器（它使用ctypes）。查看main（）函数以查看示例用法。另外，请注意我刚刚编写它，因此它可能包含错误。请谨慎使用。
#!/bin/bash
import sys
import platform
import ctypes
"""
cudart.py: used to access pars of the CUDA runtime library.
Most of this code was lifted from the pystream project (it's BSD licensed):
http://code.google.com/p/pystream
Note that this is likely to only work with CUDA 2.3
To extend to other versions, you may need to edit the DeviceProp Class
"""
cudaSuccess = 0
errorDict = {
1: 'MissingConfigurationError',
2: 'MemoryAllocationError',
3: 'InitializationError',
4: 'LaunchFailureError',
5: 'PriorLaunchFailureError',
6: 'LaunchTimeoutError',
7: 'LaunchOutOfResourcesError',
8: 'InvalidDeviceFunctionError',
9: 'InvalidConfigurationError',
10: 'InvalidDeviceError',
11: 'InvalidValueError',
12: 'InvalidPitchValueError',
13: 'InvalidSymbolError',
14: 'MapBufferObjectFailedError',
15: 'UnmapBufferObjectFailedError',
16: 'InvalidHostPointerError',
17: 'InvalidDevicePointerError',
18: 'InvalidTextureError',
19: 'InvalidTextureBindingError',
20: 'InvalidChannelDescriptorError',
21: 'InvalidMemcpyDirectionError',
22: 'AddressOfConstantError',
23: 'TextureFetchFailedError',
24: 'TextureNotBoundError',
25: 'SynchronizationError',
26: 'InvalidFilterSettingError',
27: 'InvalidNormSettingError',
28: 'MixedDeviceExecutionError',
29: 'CudartUnloadingError',
30: 'UnknownError',
31: 'NotYetImplementedError',
32: 'MemoryValueTooLargeError',
33: 'InvalidResourceHandleError',
34: 'NotReadyError',
0x7f: 'StartupFailureError',
10000: 'ApiFailureBaseError'}
try:
if platform.system() == "Microsoft":
_libcudart = ctypes.windll.LoadLibrary('cudart.dll')
elif platform.system()=="Darwin":
_libcudart = ctypes.cdll.LoadLibrary('libcudart.dylib')
else:
_libcudart = ctypes.cdll.LoadLibrary('libcudart.so')
_libcudart_error = None
except OSError, e:
_libcudart_error = e
_libcudart = None
def _checkCudaStatus(status):
if status != cudaSuccess:
eClassString = errorDict[status]
# Get the class by name from the top level of this module
eClass = globals()[eClassString]
raise eClass()
def _checkDeviceNumber(device):
assert isinstance(device, int), "device number must be an int"
assert device >= 0, "device number must be greater than 0"
assert device < 2**8-1, "device number must be < 255"
# cudaDeviceProp
class DeviceProp(ctypes.Structure):
_fields_ = [
("name", 256*ctypes.c_char), # < ASCII string identifying device
("totalGlobalMem", ctypes.c_size_t), # < Global memory available on device in bytes
("sharedMemPerBlock", ctypes.c_size_t), # < Shared memory available per block in bytes
("regsPerBlock", ctypes.c_int), # < 32-bit registers available per block
("warpSize", ctypes.c_int), # < Warp size in threads
("memPitch", ctypes.c_size_t), # < Maximum pitch in bytes allowed by memory copies
("maxThreadsPerBlock", ctypes.c_int), # < Maximum number of threads per block
("maxThreadsDim", 3*ctypes.c_int), # < Maximum size of each dimension of a block
("maxGridSize", 3*ctypes.c_int), # < Maximum size of each dimension of a grid
("clockRate", ctypes.c_int), # < Clock frequency in kilohertz
("totalConstMem", ctypes.c_size_t), # < Constant memory available on device in bytes
("major", ctypes.c_int), # < Major compute capability
("minor", ctypes.c_int), # < Minor compute capability
("textureAlignment", ctypes.c_size_t), # < Alignment requirement for textures
("deviceOverlap", ctypes.c_int), # < Device can concurrently copy memory and execute a kernel
("multiProcessorCount", ctypes.c_int), # < Number of multiprocessors on device
("kernelExecTimeoutEnabled", ctypes.c_int), # < Specified whether there is a run time limit on kernels
("integrated", ctypes.c_int), # < Device is integrated as opposed to discrete
("canMapHostMemory", ctypes.c_int), # < Device can map host memory with cudaHostAlloc/cudaHostGetDevicePointer
("computeMode", ctypes.c_int), # < Compute mode (See ::cudaComputeMode)
("__cudaReserved", 36*ctypes.c_int),
]
def __str__(self):
return """NVidia GPU Specifications:
Name: %s
Total global mem: %i
Shared mem per block: %i
Registers per block: %i
Warp size: %i
Mem pitch: %i
Max threads per block: %i
Max treads dim: (%i, %i, %i)
Max grid size: (%i, %i, %i)
Total const mem: %i
Compute capability: %i.%i
Clock Rate (GHz): %f
Texture alignment: %i
""" % (self.name, self.totalGlobalMem, self.sharedMemPerBlock,
self.regsPerBlock, self.warpSize, self.memPitch,
self.maxThreadsPerBlock,
self.maxThreadsDim[0], self.maxThreadsDim[1], self.maxThreadsDim[2],
self.maxGridSize[0], self.maxGridSize[1], self.maxGridSize[2],
self.totalConstMem, self.major, self.minor,
float(self.clockRate)/1.0e6, self.textureAlignment)
def cudaGetDeviceCount():
if _libcudart is None: return 0
deviceCount = ctypes.c_int()
status = _libcudart.cudaGetDeviceCount(ctypes.byref(deviceCount))
_checkCudaStatus(status)
return deviceCount.value
def getDeviceProperties(device):
if _libcudart is None: return None
_checkDeviceNumber(device)
props = DeviceProp()
status = _libcudart.cudaGetDeviceProperties(ctypes.byref(props), device)
_checkCudaStatus(status)
return props
def getDriverVersion():
if _libcudart is None: return None
version = ctypes.c_int()
_libcudart.cudaDriverGetVersion(ctypes.byref(version))
v = "%d.%d" % (version.value//1000,
version.value%100)
return v
def getRuntimeVersion():
if _libcudart is None: return None
version = ctypes.c_int()
_libcudart.cudaRuntimeGetVersion(ctypes.byref(version))
v = "%d.%d" % (version.value//1000,
version.value%100)
return v
def getGpuCount():
count=0
for ii in range(cudaGetDeviceCount()):
props = getDeviceProperties(ii)
if props.major!=9999: count+=1
return count
def getLoadError():
return _libcudart_error
version = getDriverVersion()
if version is not None and not version.startswith('2.3'):
sys.stdout.write("WARNING: Driver version %s may not work with %s\n" %
(version, sys.argv[0]))
version = getRuntimeVersion()
if version is not None and not version.startswith('2.3'):
sys.stdout.write("WARNING: Runtime version %s may not work with %s\n" %
(version, sys.argv[0]))
def main():
sys.stdout.write("Driver version: %s\n" % getDriverVersion())
sys.stdout.write("Runtime version: %s\n" % getRuntimeVersion())
nn = cudaGetDeviceCount()
sys.stdout.write("Device count: %s\n" % nn)
for ii in range(nn):
props = getDeviceProperties(ii)
sys.stdout.write("\nDevice %d:\n" % ii)
#sys.stdout.write("%s" % props)
for f_name, f_type in props._fields_:
attr = props.__getattribute__(f_name)
sys.stdout.write( " %s: %s\n" % (f_name, attr))
gpuCount = getGpuCount()
if gpuCount > 0:
sys.stdout.write("\n")
sys.stdout.write("GPU count: %d\n" % getGpuCount())
e = getLoadError()
if e is not None:
sys.stdout.write("There was an error loading a library:\n%s\n\n" % e)
if __name__=="__main__":
main()
答案 3 :(得分：3)
如果找到cuda，您可以编译小型GPU查询程序。这是一个简单的，你可以采纳的需求：
#include <stdlib.h>
#include <stdio.h>
#include <cuda.h>
#include <cuda_runtime.h>
int main(int argc, char** argv) {
int ct,dev;
cudaError_t code;
struct cudaDeviceProp prop;
cudaGetDeviceCount(&ct);
code = cudaGetLastError();
if(code) printf("%s\n", cudaGetErrorString(code));
if(ct == 0) {
printf("Cuda device not found.\n");
exit(0);
}
printf("Found %i Cuda device(s).\n",ct);
for (dev = 0; dev < ct; ++dev) {
printf("Cuda device %i\n", dev);
cudaGetDeviceProperties(&prop,dev);
printf("\tname : %s\n", prop.name);
printf("\ttotalGlobablMem: %lu\n", (unsigned long)prop.totalGlobalMem);
printf("\tsharedMemPerBlock: %i\n", prop.sharedMemPerBlock);
printf("\tregsPerBlock: %i\n", prop.regsPerBlock);
printf("\twarpSize: %i\n", prop.warpSize);
printf("\tmemPitch: %i\n", prop.memPitch);
printf("\tmaxThreadsPerBlock: %i\n", prop.maxThreadsPerBlock);
printf("\tmaxThreadsDim: %i, %i, %i\n", prop.maxThreadsDim[0], prop.maxThreadsDim[1], prop.maxThreadsDim[2]);
printf("\tmaxGridSize: %i, %i, %i\n", prop.maxGridSize[0], prop.maxGridSize[1], prop.maxGridSize[2]);
printf("\tclockRate: %i\n", prop.clockRate);
printf("\ttotalConstMem: %i\n", prop.totalConstMem);
printf("\tmajor: %i\n", prop.major);
printf("\tminor: %i\n", prop.minor);
printf("\ttextureAlignment: %i\n", prop.textureAlignment);
printf("\tdeviceOverlap: %i\n", prop.deviceOverlap);
printf("\tmultiProcessorCount: %i\n", prop.multiProcessorCount);
}
}
答案 4 :(得分：1)
一种有用的方法是运行CUDA已安装的程序，例如nvidia-smi，以查看它们返回的内容。
find_program(_nvidia_smi "nvidia-smi") if (_nvidia_smi) set(DETECT_GPU_COUNT_NVIDIA_SMI 0) # execute nvidia-smi -L to get a short list of GPUs available exec_program(${_nvidia_smi_path} ARGS -L OUTPUT_VARIABLE _nvidia_smi_out RETURN_VALUE _nvidia_smi_ret) # process the stdout of nvidia-smi if (_nvidia_smi_ret EQUAL 0) # convert string with newlines to list of strings string(REGEX REPLACE "\n" ";" _nvidia_smi_out "${_nvidia_smi_out}") foreach(_line ${_nvidia_smi_out}) if (_line MATCHES "^GPU [0-9]+:") math(EXPR DETECT_GPU_COUNT_NVIDIA_SMI "${DETECT_GPU_COUNT_NVIDIA_SMI}+1") # the UUID is not very useful for the user, remove it string(REGEX REPLACE " \\(UUID:.*\\)" "" _gpu_info "${_line}") if (NOT _gpu_info STREQUAL "") list(APPEND DETECT_GPU_INFO "${_gpu_info}") endif() endif() endforeach() check_num_gpu_info(${DETECT_GPU_COUNT_NVIDIA_SMI} DETECT_GPU_INFO) set(DETECT_GPU_COUNT ${DETECT_GPU_COUNT_NVIDIA_SMI}) endif() endif()
还可以查询linux / proc或lspci。请参阅https://github.com/gromacs/gromacs/blob/master/cmake/gmxDetectGpu.cmake
中完整工作的CMake示例