94 lines
6.0 KiB
Markdown
94 lines
6.0 KiB
Markdown
# CUDA 程序的错误检测
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------
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## 检测 CUDA 运行时错误的宏函数
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定义检查 cuda 运行时 API 返回值 `cudaError_t` 的宏函数。
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#define CHECK(call) \
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do { \
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const cudaError_t error_code = call; \
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if (error_code != cudaSuccess) \
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{ \
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printf("CUDA ERROR: \n"); \
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printf(" FILE: %s\n", __FILE__); \
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printf(" LINE: %d\n", __LINE__); \
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printf(" ERROR CODE: %d\n", error_code); \
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printf(" ERROR TEXT: %s\n", cudaGetErrorString(error_code)); \
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exit(1); \
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} \
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}while(0);
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因为核函数没有返回值，所以无法直接检查核函数错误。间接的方法是，在调用核函数后执行：
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CHECK(cudaGetLastError()); // 捕捉同步前的最后一个错误。
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CHECK(cudaDeviceSynchronize()); // 同步主机和设备。
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核函数的调用是 **异步的**，即主机调用核函数后不会等待核函数执行完成、而是立刻执行之后的语句。
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同步操作较为耗时，一般尽量避免；同时，只要在核函数调用后还有对其他任何能返回错误值的 API
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函数进行同步调用，都会触发主机和设备的同步并捕捉到核函数中可能发生的错误。
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此外，主机和设备之间的数据拷贝会隐式地同步主机和设备。一般要获得精确的出错位置，还是需要显式地
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同步，例如调用 `cudaDeviceSynchronize()`。
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或者，通过设置环境变量 `CUDA_LAUNCH_BLOCKING` 为 1，这样所有核函数的调用都将不再是异步的，
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而是同步的。就是说，主机调用一个核函数之后必须等待其执行完，才能向下执行。
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一般仅用于程序调试。
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------
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## CUDA-MEMCHECK 检查内存错误
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CUDA 提供了 CUDA-MEMCHECK 的工具集，包括 memcheck, racecheck, initcheck, synccheck.
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>> cuda-memcheck --tool memcheck [options] app-name [options]
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对于 memcheck 工具，可以简化为：
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>> cuda-memcheck [options] app-name [options]
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对于本例，可以通过如下方式检测错误：
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>> cuda-memcheck ./bin/check.exe
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========= CUDA-MEMCHECK
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CUDA ERROR:
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FILE: check.cu
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LINE: 56
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ERROR CODE: 9
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ERROR TEXT: invalid configuration argument
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========= Program hit cudaErrorInvalidConfiguration (error 9) due to "invalid configuration argument" on CUDA API call to cudaLaunchKernel.
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========= Saved host backtrace up to driver entry point at error
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========= Host Frame:C:\Windows\system32\DriverStore\FileRepository\nvhq.inf_amd64_5550755be1247d27\nvcuda64.dll (cuProfilerStop + 0x97c18) [0x2b8ca8]
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========= Host Frame:C:\Windows\system32\DriverStore\FileRepository\nvhq.inf_amd64_5550755be1247d27\nvcuda64.dll (cuProfilerStop + 0x9a2da) [0x2bb36a]
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========= Host Frame:C:\Windows\system32\DriverStore\FileRepository\nvhq.inf_amd64_5550755be1247d27\nvcuda64.dll [0x7b52e]
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========= Host Frame:C:\Windows\system32\DriverStore\FileRepository\nvhq.inf_amd64_5550755be1247d27\nvcuda64.dll (cuProfilerStop + 0x11ceaa) [0x33df3a]
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========= Host Frame:C:\Windows\system32\DriverStore\FileRepository\nvhq.inf_amd64_5550755be1247d27\nvcuda64.dll (cuProfilerStop + 0x137532) [0x3585c2]
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========= Host Frame:D:\3_codes\CudaSteps\capter4\bin\check.exe [0x1679]
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========= Host Frame:D:\3_codes\CudaSteps\capter4\bin\check.exe [0xd32b]
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========= Host Frame:D:\3_codes\CudaSteps\capter4\bin\check.exe [0xd1a8]
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========= Host Frame:D:\3_codes\CudaSteps\capter4\bin\check.exe [0xc6a1]
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========= Host Frame:D:\3_codes\CudaSteps\capter4\bin\check.exe [0xcbf8]
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========= Host Frame:D:\3_codes\CudaSteps\capter4\bin\check.exe [0xd944]
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========= Host Frame:C:\Windows\System32\KERNEL32.DLL (BaseThreadInitThunk + 0x14) [0x17034]
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========= Host Frame:C:\Windows\SYSTEM32\ntdll.dll (RtlUserThreadStart + 0x21) [0x52651]
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=========
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========= Program hit cudaErrorInvalidConfiguration (error 9) due to "invalid configuration argument" on CUDA API call to cudaGetLastError.
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========= Saved host backtrace up to driver entry point at error
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========= Host Frame:C:\Windows\system32\DriverStore\FileRepository\nvhq.inf_amd64_5550755be1247d27\nvcuda64.dll (cuProfilerStop + 0x97c18) [0x2b8ca8]
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========= Host Frame:C:\Windows\system32\DriverStore\FileRepository\nvhq.inf_amd64_5550755be1247d27\nvcuda64.dll (cuProfilerStop + 0x9a2da) [0x2bb36a]
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========= Host Frame:C:\Windows\system32\DriverStore\FileRepository\nvhq.inf_amd64_5550755be1247d27\nvcuda64.dll [0x7b52e]
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========= Host Frame:C:\Windows\system32\DriverStore\FileRepository\nvhq.inf_amd64_5550755be1247d27\nvcuda64.dll (cuProfilerStop + 0x11ceaa) [0x33df3a]
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========= Host Frame:C:\Windows\system32\DriverStore\FileRepository\nvhq.inf_amd64_5550755be1247d27\nvcuda64.dll (cuProfilerStop + 0x137532) [0x3585c2]
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========= Host Frame:D:\3_codes\CudaSteps\capter4\bin\check.exe [0x1461]
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========= Host Frame:D:\3_codes\CudaSteps\capter4\bin\check.exe [0xcbfd]
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========= Host Frame:D:\3_codes\CudaSteps\capter4\bin\check.exe [0xd944]
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========= Host Frame:C:\Windows\System32\KERNEL32.DLL (BaseThreadInitThunk + 0x14) [0x17034]
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========= Host Frame:C:\Windows\SYSTEM32\ntdll.dll (RtlUserThreadStart + 0x21) [0x52651]
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=========
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========= ERROR SUMMARY: 2 errors
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关于 CUDA-MEMCHECK 的更多内容，详见: [CUDA-MEMCHECK](https://docs.nvidia.com/cuda/cuda-memcheck/index.html)。
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------
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