我正在尝试在我的Jupyter Notebook上使用AWS p2.xlarge实例上的GPU而不是CPU来训练我的模型。我正在使用tensorflow-gpu后端（只安装并在requirements.txt中提到了tensorflow-gpu而不是tensorflow）。
训练模型时，我没有看到任何与使用CPU相比的速度提高，事实上，每个时代的训练速度几乎与我在4核笔记本电脑CPU上得到的速度相同（p2.xlarge还具有带有Tesla K80 GPU的4个虚拟CPU）。我不确定是否需要对我的代码进行一些更改以适应GPU可以提供的更快/并行处理。我在下面贴出了我的模型代码：
model = Sequential()
model.add(recurrent.LSTM(64, input_shape=(X_np.shape[1], X_np.shape[2]),
return_sequences=True))
model.add(recurrent.LSTM(64, return_sequences = False))
model.add(core.Dropout(0.1))
model.add(core.Dense(3, activation='softmax'))
model.compile(loss = 'categorical_crossentropy', optimizer = 'rmsprop', metrics=['accuracy'])
model.fit(X_np, y_np, epochs=100, validation_split=0.25)
有趣的是，每次我使用nvidia-smi检查GPU状态时，GPU似乎都利用了50％-60％的处理能力和几乎所有的内存（但在不训练时两者均降至0％和1MiB）：
+-----------------------------------------------------------------------------+
| NVIDIA-SMI 384.81 Driver Version: 384.81 |
|-------------------------------+----------------------+----------------------+
| 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 K80 On | 00000000:00:1E.0 Off | 0 |
| N/A 47C P0 73W / 149W | 10919MiB / 11439MiB | 52% Default |
+-------------------------------+----------------------+----------------------+
+-----------------------------------------------------------------------------+
| Processes: GPU Memory |
| GPU PID Type Process name Usage |
|=============================================================================|
| 0 1665 C ...ubuntu/aDash/MLenv/bin/python 10906MiB |
+-----------------------------------------------------------------------------+
如果您想查看我在Jupyter Notebook中使用GPU的记录，请参见以下日志：
[I 04:21:59.390 NotebookApp] Kernel started: c17bc4d1-fa15-4b0e-b5f0-87f90e56bf65
[I 04:22:02.241 NotebookApp] Adapting to protocol v5.1 for kernel c17bc4d1-fa15-4b0e-b5f0-87f90e56bf65
2017-11-30 04:22:32.403981: I tensorflow/core/platform/cpu_feature_guard.cc:137] Your CPU supports instructions that this TensorFlow binary was not compiled to use: SSE4.1 SSE4.2 AVX AVX2 FMA
2017-11-30 04:22:33.653681: I tensorflow/stream_executor/cuda/cuda_gpu_executor.cc:892] successful NUMA node read from SysFS had negative value (-1), but there must be at least one NUMA node, so returning NUMA node zero
2017-11-30 04:22:33.654041: I tensorflow/core/common_runtime/gpu/gpu_device.cc:1030] Found device 0 with properties:
name: Tesla K80 major: 3 minor: 7 memoryClockRate(GHz): 0.8235
pciBusID: 0000:00:1e.0
totalMemory: 11.17GiB freeMemory: 11.10GiB
2017-11-30 04:22:33.654070: I tensorflow/core/common_runtime/gpu/gpu_device.cc:1120] Creating TensorFlow device (/device:GPU:0) -> (device: 0, name: Tesla K80, pci bus id: 0000:00:1e.0, compute capability: 3.7)
2017-11-30 04:22:34.014329: I tensorflow/core/common_runtime/gpu/gpu_device.cc:1120] Creating TensorFlow device (/device:GPU:0) -> (device: 0, name: Tesla K80, pci bus id: 0000:00:1e.0, compute capability: 3.7)
Device mapping:
/job:localhost/replica:0/task:0/device:GPU:0 -> device: 0, name: Tesla K80, pci bus id: 0000:00:1e.0, compute capability: 3.7
2017-11-30 04:22:34.015339: I tensorflow/core/common_runtime/direct_session.cc:299] Device mapping:
/job:localhost/replica:0/task:0/device:GPU:0 -> device: 0, name: Tesla K80, pci bus id: 0000:00:1e.0, compute capability: 3.7
2017-11-30 04:23:22.426895: I tensorflow/core/common_runtime/gpu/gpu_device.cc:1120] Creating TensorFlow device (/device:GPU:0) -> (device: 0, name: Tesla K80, pci bus id: 0000:00:1e.0, compute capability: 3.7)