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Comparing Google’s TPUv2 against Nvidia’s V100 on ResNet-50

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Re: Comparing Google’s TPUv2 against Nvidia’s V100 on ResNet-50

#61

Thanks for sharing and very insightful. Guess the TPUs are the real deal. About 1/2 the cost for similar performance. Would assume Google is able to do that because of the less power required. I am actually more curious to get a paper on the new speech NN Google is using. Suppose to be 16k samples a second through a NN is hard to imagine how they did that and was able to roll it out as you would think the cost would…

The impression I got was opposite: TPU is not the hot shit that Google claims it is. Pricing is kind of irrelevant since they can subsidize this to create that story.

> Pricing is kind of irrelevant since they can subsidize this to create that story.

Depends on how much you plan to use the hardware. If it's running near continuously, total cost of ownership is very important. Power costs can quickly dominate TCO.

Re: Comparing Google’s TPUv2 against Nvidia’s V100 on ResNet-50

#62
post #7

How much detail do we know about the TPUs' design? Does Google disclose a block-diagram level? ISA details? Do they release a toolchain for low-level programming or only higher-level functions like TensorFlow? EDIT: I found [1] which describes "tensor cores", "vector/matrix units" and HBM interfaces. The design sounds similar in concept to GPUs. Maybe they don't have or need interpolation hw or other GPU features? [1…

> Maybe they don't have or need interpolation hw or other GPU features?

Definitely, no need to do any kind of rasterization here.

Re: Comparing Google’s TPUv2 against Nvidia’s V100 on ResNet-50

#63

Earlier quoted context omitted.

"As shown above, the top-1 accuracy after 90 epochs for the TPU implementation is 0.7% better. This may seem minor, but making improvements at this already very high level is extremely difficult and, depending on the application, such small improvements may make a big difference in the end." Any idea of how much variation in accuracy you get on different training runs of the same model on the same hardware? My unders…

I've been running a lot of these resnet-50 experiments lately and the run-to-run variation is very small, on the order of 0.1%. It's actually pretty amazing how consistent training is given that the initialization is always different and the data is sampled differently on each run. (As an aside, it took us about three weeks to track down a bug that was causing the model to consistently reach an accuracy 1% lower than…

Indeed, that's also my experience. ImageNet is pretty huge (although 'it's the new MNIST') so that seems to help converging to very similar solutions and accuracies.

Tracking down bugs in convergence is really costly in these settings. We had a problem in pre-processing that took us quite a while to figure out...

Re: Comparing Google’s TPUv2 against Nvidia’s V100 on ResNet-50

#64

Earlier quoted context omitted.

The impression I got was opposite: TPU is not the hot shit that Google claims it is. Pricing is kind of irrelevant since they can subsidize this to create that story.

> Pricing is kind of irrelevant since they can subsidize this to create that story. Depends on how much you plan to use the hardware. If it's running near continuously, total cost of ownership is very important. Power costs can quickly dominate TCO.

At the pricing extreme, Google could make their TPUs free to use and charge elsewhere in their cloud. This shows that literal pricing is pretty irrelevant.

Re: Comparing Google’s TPUv2 against Nvidia’s V100 on ResNet-50

#65

Earlier quoted context omitted.

"The cost performance ratio reflects this." But the TPUs are half the cost per this article? Plus Google does the entire stack and can better optimize the hardware versus Nvidia. So it seem Google can improve faster I would think. If there ever was a huge advantage doing the entire stack it is with neural networks. A perfect example is Google new speech doing 16k samples a second with a NN. https://cloudplatform.goog…

I'm not sure what you mean by google does the entire stack. Nvidia writes all of the major CUDA libraries used behind the scenes in the NN libraries, such as cuDNN, cuBLAS, etc. Nvidia can likely improve their hardware significantly faster/more efficiently than Google can because their entire business depends on it. Google has incentive for improving their TPU for internal use, but they don't make any money by sellin…

> I'm not sure what you mean by google does the entire stack.

Consider that Google has some of the best machine learning researchers, compiler engineers, hardware engineers, and infrastructure in the business working on this.

Re: Comparing Google’s TPUv2 against Nvidia’s V100 on ResNet-50

#66
post #58

Excellent work. Do you have plans to open source the scripts/implementation details used to reproduce the results? Would be great if others can also validate and repeat the experiment for future software updates (e.g. TensorFlow 1.8) as I expect there will be some performance gain for both TPU and GPU by CUDA and TensorFlow optimizations. Sidenote: Love the illustrations that accompany most of your blog posts, are th…

Happy you like the post! The implementations we used are open source (we reference the specific revisions), so reproducing results is possible right now. We haven't thought about publishing our small scripts around that (there's not much to it), but it's a good idea. There's also work towards benchmarking suites like DAWNBench (https://dawn.cs.stanford.edu/benchmark/).

The illustrations are from an artist/designer we contract from time to time. I agree, his work is awesome!

Re: Comparing Google’s TPUv2 against Nvidia’s V100 on ResNet-50

#67

Earlier quoted context omitted.

> Pricing is kind of irrelevant since they can subsidize this to create that story. Depends on how much you plan to use the hardware. If it's running near continuously, total cost of ownership is very important. Power costs can quickly dominate TCO.

At the pricing extreme, Google could make their TPUs free to use and charge elsewhere in their cloud. This shows that literal pricing is pretty irrelevant.

So could AWS/Nvidia.

Re: Comparing Google’s TPUv2 against Nvidia’s V100 on ResNet-50

#68
post #58

Excellent work. Do you have plans to open source the scripts/implementation details used to reproduce the results? Would be great if others can also validate and repeat the experiment for future software updates (e.g. TensorFlow 1.8) as I expect there will be some performance gain for both TPU and GPU by CUDA and TensorFlow optimizations. Sidenote: Love the illustrations that accompany most of your blog posts, are th…

[deleted]

Re: Comparing Google’s TPUv2 against Nvidia’s V100 on ResNet-50

#69

Earlier quoted context omitted.

Yes in the cloud as you would expect in 2018. Available to the general public.

They announced in 2016 they had TPUs. So no, I would not expect that 2 full years later they're just now being available in the public cloud. These are not new products to them; they likely just don't want to deal with supporting them in different configurations.

> they likely just don't want to deal with supporting them in different configurations.

It is a lot of work. But mainly that TPUv1 only did inference while TPUv2 does training+inference.

Re: Comparing Google’s TPUv2 against Nvidia’s V100 on ResNet-50

#70
post #51

Slower alternative: "fastai with @pytorch on @awscloud is currently the fastest to train Imagenet on GPU, fastest on a single machine (faster than Intel-caffe on 64 machines!), and fastest on public infrastructure (faster than @TensorFlow on a TPU!) Big thanks to our students that helped with this." - https://twitter.com/jeremyphoward/status/988852083796291584

One machine with 8 V100 GPUs. If you consider one TPU pod a single machine the TPU is faster. Those numbers also show that 8 GPUs are slower than 8 TPUs (so same conclusion as the article)
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