IBM XL C/C++ 编译器："No valid target devices available"

Question

我正在使用 IBM XL C/C++ 编译器编译一些 OpenMP 4.5 代码，目的是将其部分工作卸载到 GPU，如下所示：

xlc++ mycode.cpp -qsmp=omp -qreport -qoffload -std=c++11 -Wall

编译似乎成功了，只给我以下信息：

mycode.cpp:
"mycode.cpp", line 284: 1586-358 (I) Loop was parallelized.
"mycode.cpp", line 293: 1586-358 (I) Loop was parallelized.
"mycode.cpp", line 309: 1586-358 (I) Loop was parallelized.
"mycode.cpp", line 324: 1586-358 (I) Loop was parallelized.
"mycode.cpp", line 126: 1586-674 (I) Remark: Simd or nested parallel directive requires OpenMP runtime
"" 1586-671 (I) GPU OpenMP Runtime is required for offloaded kernel '__xl__Z9MyCodeiii_l123_h44039046689_OL_1'

但是，当我运行代码时，我收到以下令人不快的消息：

1587-169 No valid target devices available.

使用 nvidia-smi，我已验证目标设备实际上可用：

+-----------------------------------------------------------------------------+
| NVIDIA-SMI 384.59                 Driver Version: 384.59                    |
|-------------------------------+----------------------+----------------------+
| GPU  Name        Persistence-M| Bus-Id        Disp.A | Volatile Uncorr. ECC |
| Fan  Temp  Perf  Pwr:Usage/Cap|         Memory-Usage | GPU-Util  Compute M. |
|===============================+======================+======================|
|   0  Tesla P100-SXM2...  Off  | 00000002:01:00.0 Off |                    0 |
| N/A   33C    P0    29W / 300W |     10MiB / 16276MiB |      0%   E. Process |
+-------------------------------+----------------------+----------------------+
|   1  Tesla P100-SXM2...  Off  | 00000003:01:00.0 Off |                    0 |
| N/A   29C    P0    30W / 300W |     10MiB / 16276MiB |      0%   E. Process |
+-------------------------------+----------------------+----------------------+
|   2  Tesla P100-SXM2...  Off  | 00000006:01:00.0 Off |                    0 |
| N/A   31C    P0    28W / 300W |     10MiB / 16276MiB |      0%   E. Process |
+-------------------------------+----------------------+----------------------+
|   3  Tesla P100-SXM2...  Off  | 00000007:01:00.0 Off |                    0 |
| N/A   27C    P0    29W / 300W |     10MiB / 16276MiB |      0%   E. Process |
+-------------------------------+----------------------+----------------------+

我的想法是 XL 以某种方式针对错误的加速器，但我找不到设置它的选项。

如何让我的代码识别和利用可用的 GPU？

Answer 1

-qtgtarch 指定代码可能运行的 GPU 架构。如果您希望编译器自动检测正在执行编译器的系统的设备 0 的体系结构，请尝试 -qtgtarch=auto。或者，您可以尝试手动设置它，例如 -qtgtarch=sm_60。

更多信息请见 Knowledge Center。

IBM XL C/C++ 编译器："No valid target devices available"

IBM XL C/C++ Compiler: "No valid target devices available"

gpu

openmp

xlc