14,949 research outputs found
Distributed learning of CNNs on heterogeneous CPU/GPU architectures
Convolutional Neural Networks (CNNs) have shown to be powerful classification
tools in tasks that range from check reading to medical diagnosis, reaching
close to human perception, and in some cases surpassing it. However, the
problems to solve are becoming larger and more complex, which translates to
larger CNNs, leading to longer training times that not even the adoption of
Graphics Processing Units (GPUs) could keep up to. This problem is partially
solved by using more processing units and distributed training methods that are
offered by several frameworks dedicated to neural network training. However,
these techniques do not take full advantage of the possible parallelization
offered by CNNs and the cooperative use of heterogeneous devices with different
processing capabilities, clock speeds, memory size, among others. This paper
presents a new method for the parallel training of CNNs that can be considered
as a particular instantiation of model parallelism, where only the
convolutional layer is distributed. In fact, the convolutions processed during
training (forward and backward propagation included) represent from -\%
of global processing time. The paper analyzes the influence of network size,
bandwidth, batch size, number of devices, including their processing
capabilities, and other parameters. Results show that this technique is capable
of diminishing the training time without affecting the classification
performance for both CPUs and GPUs. For the CIFAR-10 dataset, using a CNN with
two convolutional layers, and and kernels, respectively, best
speedups achieve using four CPUs and with three GPUs.
Modern imaging datasets, larger and more complex than CIFAR-10 will certainly
require more than -\% of processing time calculating convolutions, and
speedups will tend to increase accordingly
What does fault tolerant Deep Learning need from MPI?
Deep Learning (DL) algorithms have become the de facto Machine Learning (ML)
algorithm for large scale data analysis. DL algorithms are computationally
expensive - even distributed DL implementations which use MPI require days of
training (model learning) time on commonly studied datasets. Long running DL
applications become susceptible to faults - requiring development of a fault
tolerant system infrastructure, in addition to fault tolerant DL algorithms.
This raises an important question: What is needed from MPI for de- signing
fault tolerant DL implementations? In this paper, we address this problem for
permanent faults. We motivate the need for a fault tolerant MPI specification
by an in-depth consideration of recent innovations in DL algorithms and their
properties, which drive the need for specific fault tolerance features. We
present an in-depth discussion on the suitability of different parallelism
types (model, data and hybrid); a need (or lack thereof) for check-pointing of
any critical data structures; and most importantly, consideration for several
fault tolerance proposals (user-level fault mitigation (ULFM), Reinit) in MPI
and their applicability to fault tolerant DL implementations. We leverage a
distributed memory implementation of Caffe, currently available under the
Machine Learning Toolkit for Extreme Scale (MaTEx). We implement our approaches
by ex- tending MaTEx-Caffe for using ULFM-based implementation. Our evaluation
using the ImageNet dataset and AlexNet, and GoogLeNet neural network topologies
demonstrates the effectiveness of the proposed fault tolerant DL implementation
using OpenMPI based ULFM
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