Tensorflow 1.10

1.
Building Tensorflow

Building Tensorflow allows use of SIMD CPU enhancements like AVX. Cuda 9.2 supports up to GCC7. To get the Nvidia CUDA libraries we must set the environment variable NEXTJOURNAL_MOUNT_CUDA in the runtime configuration. Tensorflow can see some speedups if we give it libjemalloc.

apt-get update >/dev/null
apt-get install -y \
  pkg-config zlib1g-dev git zip xutils-dev gnupg \
  libjemalloc-dev

update-alternatives --install /usr/bin/gcc gcc /usr/bin/gcc-7 25
update-alternatives --install /usr/bin/g++ g++ /usr/bin/g++-7 25

echo "/usr/local/cuda/extras/CUPTI/lib64" > /etc/ld.so.conf.d/cupti.conf

ldconfig

The Tensorflow compilation configure script is hardcoded to look for libnccl.so in <nccl_install_dir>/lib, but we have /lib64, so we need to set up some links to redirect it.

mkdir -p /usr/local/nccl_redir
cd /usr/local/nccl_redir
for i in `ls /usr/local/cuda`; do ln -s /usr/local/cuda/$i ./; done
ln -s lib64 lib

Install Bazel. This is very persnickity and likes to break compatibility with new versions quite often. Bazel 0.15.x is tested to work with Tensorflow 1.10.0, while 0.14.1 worked for TF 1.9.0, and 0.11.1 for 1.8.0-rc1.

export BAZEL_VERSION=0.15.2
export BAZEL_FILE=bazel-${BAZEL_VERSION}-installer-linux-x86_64.sh
wget --progress=dot:giga \
  https://github.com/bazelbuild/bazel/releases/download/$BAZEL_VERSION/$BAZEL_FILE
chmod +x $BAZEL_FILE
./$BAZEL_FILE

Clone the source and checkout the release.

git clone https://github.com/tensorflow/tensorflow
cd tensorflow
git checkout v1.10.0

This configure script uses environment variables to do a non-interactive config. The march flag set through CC_OPT_FLAGS is of particular interest for CPU-only computation, as it controls which SIMD instruction sets Tensorflow will use, which can have large performance impacts. Some important flag values:

  • nehalem: Core-i family (circa 2008) supports MMX, SSE1-4.2, and POPCNT, equivalent to the corei7 march flag pre-GCC5.
  • sandybridge: Adds AVX (large potential speedups), AES and PCLMUL, and is oldest family that the Google Cloud runs (2011). Requires GCC5+.
  • skylake: Adds a wide variety of SIMD instructions, including AVX2, and is currently the newest family the Google Cloud has. Requires GCC6+.

Also of interest for CPU computation is TF_NEED_MKL. Enabling this compiles Tensorflow to use the Intel Math Kernel Library, which is highly optimized for any CPU the Google Cloud will provide. In Tensorflow the MKL and CUDA are mutually exclusive—MKL is reserved for CPU-optimized builds.

15.6s
cd /tensorflow

export TF_ROOT="/opt/tensorflow"

export PYTHON_BIN_PATH="/opt/conda/bin/python"
export PYTHON_LIB_PATH="$($PYTHON_BIN_PATH -c 'import site; print(site.getsitepackages()[0])')"
export PYTHONPATH=${TF_ROOT}/lib
export PYTHON_ARG=${TF_ROOT}/lib

export TF_NEED_GCP=1   # Google Cloud
export TF_NEED_HDFS=1  # Hadoop Filesystem access
export TF_NEED_S3=1    # Amazon S3
export TF_NEED_AWS=0   # Amazon AWS
export TF_NEED_KAFKA=1 # Apache KAFKA

export TF_NEED_JEMALLOC=1 # Alternative malloc
export TF_NEED_GDR=0   # GPU Direct RDMA
export TF_NEED_VERBS=0 # VERBS RDMA

export TF_NEED_CUDA=1
export CUDA_TOOLKIT_PATH=/usr/local/cuda
export TF_CUDA_VERSION="$($CUDA_TOOLKIT_PATH/bin/nvcc --version | sed -n 's/^.*release \(.*\),.*/\1/p')"
export TF_CUDA_COMPUTE_CAPABILITIES=7.0,6.1,6.0,3.7 # V100, P100, P4, K80
export CUDNN_INSTALL_PATH=/usr/local/cuda
export TF_CUDNN_VERSION="$(sed -n 's/^#define CUDNN_MAJOR\s*\(.*\).*/\1/p' $CUDNN_INSTALL_PATH/include/cudnn.h)"
export TF_NEED_TENSORRT=0  # Nvidia TensorRT
#export TENSORRT_INSTALL_PATH=/usr/local/TensorRT
export NCCL_INSTALL_PATH=/usr/local/nccl_redir # Nvidia NCCL
export TF_NCCL_VERSION="$(sed -n 's/^#define NCCL_MAJOR\s*\(.*\).*/\1/p' $NCCL_INSTALL_PATH/include/nccl.h)"
export TF_CUDA_CLANG=0    # Use clang compiler instead of nvcc

export TF_NEED_OPENCL=0
export TF_NEED_OPENCL_SYCL=0
export TF_ENABLE_XLA=0    # Accelerated Linear Algebra JIT compiler
export TF_NEED_MKL=0       # Intel Math Kernel Library
export TF_DOWNLOAD_MKL=0
export TF_NEED_MPI=0       # Message Passing Interface
export TF_SET_ANDROID_WORKSPACE=0

export GCC_HOST_COMPILER_PATH=$(which gcc)
export CC_OPT_FLAGS="-march=sandybridge"

./configure

Finally, the build—this takes over two hours.

export LD_LIBRARY_PATH="/usr/local/cuda/lib64:/usr/local/nvidia/lib64"
export CUDNN_INCLUDE_DIR="/usr/local/cuda/include"
export CUDNN_LIBRARY="/usr/local/cuda/lib64/libcudnn.so"
export TMP="/tmp"

cd /tensorflow
bazel build --config=opt --config=cuda --verbose_failures --jobs 5 \
  --action_env="LD_LIBRARY_PATH=${LD_LIBRARY_PATH}" \
  --action_env="CUDNN_INCLUDE_DIR=${CUDNN_INCLUDE_DIR}" \
  --action_env="CUDNN_LIBRARY=${CUDNN_LIBRARY}" \
  //tensorflow/tools/pip_package:build_pip_package 

We'll export this environment just in case anyone wants to play with the compiled result, but the important part here is the creation of a .whl wheel file which can be installed via pip.

cd /tensorflow
bazel-bin/tensorflow/tools/pip_package/build_pip_package /tmp/tensorflow_pkg
cp /tmp/tensorflow_pkg/tensorflow*.whl /results/
tensorflow-1.10.0-cp36-cp36m-linux_x86_64.whl

Finally, we'll install the package we created in a clean environment.

# preemptively install deps
conda install -c anaconda -c intel \
  absl-py astor gast grpcio markdown protobuf termcolor werkzeug \
  cython jemalloc

# pip needs a specific filename format
TF_FILE="tensorflow-1.10.0-cp36-cp36m-linux_x86_64.whl"
cp tensorflow-1.10.0-cp36-cp36m-linux_x86_64.whl \
  $TF_FILE
pip install $TF_FILE
rm $TF_FILE

ldconfig

2.
Use Case

We'll follow the deep convolutional generative adversarial networks (DCGAN) example by Aymeric Damien, from the Tensorflow Examples project, to generate digit images from a noise distribution.

Reference paper: Unsupervised representation learning with deep convolutional generative adversarial networks. A Radford, L Metz, S Chintala. arXiv:1511.06434.

First, parameters.

# Training Params
num_steps = 5000
batch_size = 32

# Network Params
image_dim = 784 # 28*28 pixels * 1 channel
gen_hidden_dim = 256
disc_hidden_dim = 256
noise_dim = 200 # Noise data points

Define networks.

0.0s
# Generator Network
# Input: Noise, Output: Image
def generator(x, reuse=False):
    with tf.variable_scope('Generator', reuse=reuse):
        # TensorFlow Layers automatically create variables and calculate their
        # shape, based on the input.
        x = tf.layers.dense(x, units=6 * 6 * 128)
        x = tf.nn.tanh(x)
        # Reshape to a 4-D array of images: (batch, height, width, channels)
        # New shape: (batch, 6, 6, 128)
        x = tf.reshape(x, shape=[-1, 6, 6, 128])
        # Deconvolution, image shape: (batch, 14, 14, 64)
        x = tf.layers.conv2d_transpose(x, 64, 4, strides=2)
        # Deconvolution, image shape: (batch, 28, 28, 1)
        x = tf.layers.conv2d_transpose(x, 1, 2, strides=2)
        # Apply sigmoid to clip values between 0 and 1
        x = tf.nn.sigmoid(x)
        return x

# Discriminator Network
# Input: Image, Output: Prediction Real/Fake Image
def discriminator(x, reuse=False):
    with tf.variable_scope('Discriminator', reuse=reuse):
        # Typical convolutional neural network to classify images.
        x = tf.layers.conv2d(x, 64, 5)
        x = tf.nn.tanh(x)
        x = tf.layers.average_pooling2d(x, 2, 2)
        x = tf.layers.conv2d(x, 128, 5)
        x = tf.nn.tanh(x)
        x = tf.layers.average_pooling2d(x, 2, 2)
        x = tf.contrib.layers.flatten(x)
        x = tf.layers.dense(x, 1024)
        x = tf.nn.tanh(x)
        # Output 2 classes: Real and Fake images
        x = tf.layers.dense(x, 2)
    return x

Network setup.

9.0s
import matplotlib.pyplot as plt
import numpy as np
import tensorflow as tf

# Import MNIST data (http://yann.lecun.com/exdb/mnist/)
from tensorflow.examples.tutorials.mnist import input_data
mnist = input_data.read_data_sets("/tmp/data/", one_hot=True)

# Build Networks
# Network Inputs
noise_input = tf.placeholder(tf.float32, shape=[None, noise_dim])
real_image_input = tf.placeholder(tf.float32, shape=[None, 28, 28, 1])

# Build Generator Network
gen_sample = generator(noise_input)

# Build 2 Discriminator Networks (one from noise input, one from generated samples)
disc_real = discriminator(real_image_input)
disc_fake = discriminator(gen_sample, reuse=True)
disc_concat = tf.concat([disc_real, disc_fake], axis=0)

# Build the stacked generator/discriminator
stacked_gan = discriminator(gen_sample, reuse=True)

# Build Targets (real or fake images)
disc_target = tf.placeholder(tf.int32, shape=[None])
gen_target = tf.placeholder(tf.int32, shape=[None])

# Build Loss
disc_loss = tf.reduce_mean(tf.nn.sparse_softmax_cross_entropy_with_logits(
    logits=disc_concat, labels=disc_target))
gen_loss = tf.reduce_mean(tf.nn.sparse_softmax_cross_entropy_with_logits(
    logits=stacked_gan, labels=gen_target))

# Build Optimizers
optimizer_gen = tf.train.AdamOptimizer(learning_rate=0.001)
optimizer_disc = tf.train.AdamOptimizer(learning_rate=0.001)

# Training Variables for each optimizer
# By default in TensorFlow, all variables are updated by each optimizer, so we
# need to precise for each one of them the specific variables to update.
# Generator Network Variables
gen_vars = tf.get_collection(tf.GraphKeys.TRAINABLE_VARIABLES, scope='Generator')
# Discriminator Network Variables
disc_vars = tf.get_collection(tf.GraphKeys.TRAINABLE_VARIABLES, scope='Discriminator')

# Create training operations
train_gen = optimizer_gen.minimize(gen_loss, var_list=gen_vars)
train_disc = optimizer_disc.minimize(disc_loss, var_list=disc_vars)

# Initialize the variables (i.e. assign their default value)
init = tf.global_variables_initializer()

Finally, training.

79.2s
# Start training
sess = tf.Session()

# Run the initializer
sess.run(init)

for step in range(1, num_steps+1):

	# Prepare Input Data
	# Get the next batch of MNIST data (only images are needed, not labels)
	batch_x, _ = mnist.train.next_batch(batch_size)
	batch_x = np.reshape(batch_x, newshape=[-1, 28, 28, 1])
	# Generate noise to feed to the generator
	z = np.random.uniform(-1., 1., size=[batch_size, noise_dim])

	# Prepare Targets (Real image: 1, Fake image: 0)
	# The first half of data fed to the generator are real images,
	# the other half are fake images (coming from the generator).
	batch_disc_y = np.concatenate(
		[np.ones([batch_size]), np.zeros([batch_size])], axis=0)
	# Generator tries to fool the discriminator, thus targets are 1.
	batch_gen_y = np.ones([batch_size])

	# Training
	feed_dict = {real_image_input: batch_x, noise_input: z,
				 disc_target: batch_disc_y, gen_target: batch_gen_y}
	_, _, gl, dl = sess.run([train_gen, train_disc, gen_loss, disc_loss],
							feed_dict=feed_dict)
	if step % 1000 == 0 or step == 1:
		print('Step %i: Generator Loss: %f, Discriminator Loss: %f' % (step, gl, dl))
		
		# Generate images from noise, using the generator network.
		f, a = plt.subplots(4, 10, figsize=(10, 4))
		for i in range(10):
			# Noise input.
			z = np.random.uniform(-1., 1., size=[4, noise_dim])
			g = sess.run(gen_sample, feed_dict={noise_input: z})
			for j in range(4):
				# Generate image from noise. Extend to 3 channels for matplot figure.
				img = np.reshape(np.repeat(g[j][:, :, np.newaxis], 3, axis=2),
					newshape=(28, 28, 3))
				a[j][i].imshow(img)
				
		#f.show()
		plt.suptitle("Step {}".format(step))
		plt.savefig("/results/step-{}.svg".format(step))
		plt.close()
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