Tensorflow：设备序号之间不支持对等访问
Tensorflow: Peer access not supported between device ordinals
如果我有 Peer access not supported between device ordinals，是否仍然可以 运行 在某种多 GPU 设置中进行训练？（据我所知，GPU 是 'not connected'）例如通过计算每个批次分别在 GPU 上，然后在 CPU 上合并，据我所知，这是 'batch accumulation' 在 DIGITS 中与 Caffe 后端一起工作的方式。
原始输出：
2017-05-10 15:27:54.360688: I tensorflow/core/common_runtime/gpu/gpu_device.cc:779] Peer access not supported between device ordinals 0 and 1
2017-05-10 15:27:54.360949: I tensorflow/core/common_runtime/gpu/gpu_device.cc:779] Peer access not supported between device ordinals 0 and 2
2017-05-10 15:27:54.361504: I tensorflow/core/common_runtime/gpu/gpu_device.cc:779] Peer access not supported between device ordinals 0 and 3
2017-05-10 15:27:54.361738: I tensorflow/core/common_runtime/gpu/gpu_device.cc:779] Peer access not supported between device ordinals 1 and 0
2017-05-10 15:27:54.361892: I tensorflow/core/common_runtime/gpu/gpu_device.cc:779] Peer access not supported between device ordinals 1 and 2
2017-05-10 15:27:54.362065: I tensorflow/core/common_runtime/gpu/gpu_device.cc:779] Peer access not supported between device ordinals 1 and 3
2017-05-10 15:27:54.362263: I tensorflow/core/common_runtime/gpu/gpu_device.cc:779] Peer access not supported between device ordinals 2 and 0
2017-05-10 15:27:54.362485: I tensorflow/core/common_runtime/gpu/gpu_device.cc:779] Peer access not supported between device ordinals 2 and 1
2017-05-10 15:27:54.362693: I tensorflow/core/common_runtime/gpu/gpu_device.cc:779] Peer access not supported between device ordinals 2 and 3
2017-05-10 15:27:54.362885: I tensorflow/core/common_runtime/gpu/gpu_device.cc:779] Peer access not supported between device ordinals 3 and 0
2017-05-10 15:27:54.362927: I tensorflow/core/common_runtime/gpu/gpu_device.cc:779] Peer access not supported between device ordinals 3 and 1
2017-05-10 15:27:54.362967: I tensorflow/core/common_runtime/gpu/gpu_device.cc:779] Peer access not supported between device ordinals 3 and 2
2017-05-10 15:27:54.364638: I tensorflow/core/common_runtime/gpu/gpu_device.cc:908] DMA: 0 1 2 3
2017-05-10 15:27:54.364668: I tensorflow/core/common_runtime/gpu/gpu_device.cc:918] 0: Y N N N
2017-05-10 15:27:54.364687: I tensorflow/core/common_runtime/gpu/gpu_device.cc:918] 1: N Y N N
2017-05-10 15:27:54.364702: I tensorflow/core/common_runtime/gpu/gpu_device.cc:918] 2: N N Y N
2017-05-10 15:27:54.364717: I tensorflow/core/common_runtime/gpu/gpu_device.cc:918] 3: N N N Y
此消息是良性的（它是 "INFO" 消息，不是错误）。 Tensorflow 中的所有内容都可以工作，但可能比在支持点对点访问的不同硬件上慢。
该消息表示 NVIDIA 驱动程序报告您的 GPU 之间无法进行点对点访问。请参阅：https://developer.nvidia.com/gpudirect 了解更多信息。
您可以使用命令
nvidia-smi topo -m
显示总线拓扑。
如果我有 Peer access not supported between device ordinals，是否仍然可以 运行 在某种多 GPU 设置中进行训练？（据我所知，GPU 是 'not connected'）例如通过计算每个批次分别在 GPU 上，然后在 CPU 上合并，据我所知，这是 'batch accumulation' 在 DIGITS 中与 Caffe 后端一起工作的方式。
原始输出：
2017-05-10 15:27:54.360688: I tensorflow/core/common_runtime/gpu/gpu_device.cc:779] Peer access not supported between device ordinals 0 and 1
2017-05-10 15:27:54.360949: I tensorflow/core/common_runtime/gpu/gpu_device.cc:779] Peer access not supported between device ordinals 0 and 2
2017-05-10 15:27:54.361504: I tensorflow/core/common_runtime/gpu/gpu_device.cc:779] Peer access not supported between device ordinals 0 and 3
2017-05-10 15:27:54.361738: I tensorflow/core/common_runtime/gpu/gpu_device.cc:779] Peer access not supported between device ordinals 1 and 0
2017-05-10 15:27:54.361892: I tensorflow/core/common_runtime/gpu/gpu_device.cc:779] Peer access not supported between device ordinals 1 and 2
2017-05-10 15:27:54.362065: I tensorflow/core/common_runtime/gpu/gpu_device.cc:779] Peer access not supported between device ordinals 1 and 3
2017-05-10 15:27:54.362263: I tensorflow/core/common_runtime/gpu/gpu_device.cc:779] Peer access not supported between device ordinals 2 and 0
2017-05-10 15:27:54.362485: I tensorflow/core/common_runtime/gpu/gpu_device.cc:779] Peer access not supported between device ordinals 2 and 1
2017-05-10 15:27:54.362693: I tensorflow/core/common_runtime/gpu/gpu_device.cc:779] Peer access not supported between device ordinals 2 and 3
2017-05-10 15:27:54.362885: I tensorflow/core/common_runtime/gpu/gpu_device.cc:779] Peer access not supported between device ordinals 3 and 0
2017-05-10 15:27:54.362927: I tensorflow/core/common_runtime/gpu/gpu_device.cc:779] Peer access not supported between device ordinals 3 and 1
2017-05-10 15:27:54.362967: I tensorflow/core/common_runtime/gpu/gpu_device.cc:779] Peer access not supported between device ordinals 3 and 2
2017-05-10 15:27:54.364638: I tensorflow/core/common_runtime/gpu/gpu_device.cc:908] DMA: 0 1 2 3
2017-05-10 15:27:54.364668: I tensorflow/core/common_runtime/gpu/gpu_device.cc:918] 0: Y N N N
2017-05-10 15:27:54.364687: I tensorflow/core/common_runtime/gpu/gpu_device.cc:918] 1: N Y N N
2017-05-10 15:27:54.364702: I tensorflow/core/common_runtime/gpu/gpu_device.cc:918] 2: N N Y N
2017-05-10 15:27:54.364717: I tensorflow/core/common_runtime/gpu/gpu_device.cc:918] 3: N N N Y
此消息是良性的（它是 "INFO" 消息，不是错误）。 Tensorflow 中的所有内容都可以工作，但可能比在支持点对点访问的不同硬件上慢。
该消息表示 NVIDIA 驱动程序报告您的 GPU 之间无法进行点对点访问。请参阅：https://developer.nvidia.com/gpudirect 了解更多信息。
您可以使用命令
nvidia-smi topo -m
显示总线拓扑。