Live data from Hacker News

Cloud TPU Pods Break AI Training Records

cloud.google.com

31–40 of 48 posts

Re: Cloud TPU Pods Break AI Training Records

#31
post #10
post #8

Earlier quoted context omitted.

You might want to check the DAWN benchmark, it does just that: [1] https://dawn.cs.stanford.edu/benchmark/index.html#imagenet-t...

Thanks, I've seen dawnbench, and it's definitely better than this presentation. Unfortunately, their cost numbers aren't actual cost, as they don't allow using AWS spot instance pricing (which is what fast.ai does). https://www.fast.ai/2018/04/30/dawnbench-fastai/

Divide by 3 to get pre-emptible price

Re: Cloud TPU Pods Break AI Training Records

#32
post #19
post #6

It's disappointing there is no attempt at normalizing results. It's not perf/$, or perf/W, or perf/chip, or anything that might be useful - it seems to just be perf/(the largest machine google/nvidia could afford to put together for a given benchmark). Seriously. Transformer: 1024 TPUs are twice as fast as 480 GPUs. Resnet50: 1536 GPUs are about as fast as 1024 TPUs. SSD: 1024 TPUs are twice as fast as 240 GPUs. Grea…

Author of the blog post here. Cloud TPUs are designed to maximize performance-per-dollar, so you are right that pure performance comparisons at maximum scale don't tell the whole story. The most straightforward performance-per-dollar comparisons would be among several different hardware configurations across the major public clouds. However, we haven't yet seen any other public cloud MLPerf submissions at scales comp…

Can you elaborate on the performance-per-dollar part? IE, I'm seeing GCP providing V100 at $2.48/hour and a TPUv3 at $8.00/hour

Re: Cloud TPU Pods Break AI Training Records

#33
post #19

Earlier quoted context omitted.

Author of the blog post here. Cloud TPUs are designed to maximize performance-per-dollar, so you are right that pure performance comparisons at maximum scale don't tell the whole story. The most straightforward performance-per-dollar comparisons would be among several different hardware configurations across the major public clouds. However, we haven't yet seen any other public cloud MLPerf submissions at scales comp…

Can you elaborate on the performance-per-dollar part? IE, I'm seeing GCP providing V100 at $2.48/hour and a TPUv3 at $8.00/hour

Probably Google is still doing that 1 "Cloud TPUv3" = 4 TPUv3 chips.

Re: Cloud TPU Pods Break AI Training Records

#34
post #13

Earlier quoted context omitted.

When Moores law is finally dead and buried (e.g. 5nm), new architectures will be all that's left. Seems like a great time to start down the new architecture path.

Have semiconductor companies not been on the new architecture path already? It's not like they've just been doing die shrinks this whole time.

Yes, but the emphasis now is much greater than before. The old rules of turn the scaling crank that defined the industry for decades are no longer helping.

Re: Cloud TPU Pods Break AI Training Records

#35
post #4

What's in the picture? Can't figure out the scale. Are those like server racks or breadboards or ...?

All you see is 8 server racks with colored network cables, switches and power supplies. The TPU ASICs themselves make up just a tiny part of this datacenter, you also have the printed circuit boards, cooling fins, 8x48 metal boxes, power and network cables, DC/DC or AC/DC converters at the bottom, fans or water tubes for cooling and airgaps.

My startup is trying to develop wafer scale integration where you collapse 2 racks of the network, metal boxes, power and cooling into a 300mm wafer immersed a 100 mm x 400mm box with a few fibers and three power cables coming out. That can save around 900% of the capital cost and orders of magnitude of power (especially if you put the box in a building where the waste heat is not wasted but used to heat water for showering and space heating).

As it is now, these datacenter customers and hyperscalers don't seem to care about the enormous waste and cost of paying for inefficient hardware. Considering the enormous cost and carbon emmission savings a wafer scale integration would bring (and the competitive advantage), you would be suprised how hard it is to get funding from them to develop it.

I suspect is also the main reason they don't care to publish normalized benchmarks for $/performance/joule, as it would demonstrate how wasteful it all is.

Re: Cloud TPU Pods Break AI Training Records

#36
post #29
post #19

Earlier quoted context omitted.

Author of the blog post here. Cloud TPUs are designed to maximize performance-per-dollar, so you are right that pure performance comparisons at maximum scale don't tell the whole story. The most straightforward performance-per-dollar comparisons would be among several different hardware configurations across the major public clouds. However, we haven't yet seen any other public cloud MLPerf submissions at scales comp…

Why performance per dollar over performance per watt? Performance per watt doesn't care where the systems are (on-prem vs cloud) and should track perf/$ (unless perf/$ is mostly determined by subsidies).

I think hardware acquisition costs can dominate GPU prices, so perf/watt might not be a realistic measure for the cost of running such large scale/high performance experiments.

For instance, the DGX-2 has an MSRP of $399,000 and consumes 10 kW of power [1]. The average commercial electricity cost across the US is about $0.11/kWh [2], so a DGX-2 running at full tilt costs $1.10 an hour in electricity. Thus, a DGX-2 running at 100% utilization for 3 years costs $9,636 in electricity, which is ~2.5% of the cost of the box itself.

Of course, you probably could get DGX-2s for a lot cheaper if you are buying 100 of them, but the acquisition costs are still going to be significant vis-a-vis power costs.

[1]: https://www.anandtech.com/show/12587/nvidias-dgx2-sixteen-v1...

[2]: https://www.pacificpower.net/about/rr/cpc.html

Re: Cloud TPU Pods Break AI Training Records

#37
post #19
post #6

It's disappointing there is no attempt at normalizing results. It's not perf/$, or perf/W, or perf/chip, or anything that might be useful - it seems to just be perf/(the largest machine google/nvidia could afford to put together for a given benchmark). Seriously. Transformer: 1024 TPUs are twice as fast as 480 GPUs. Resnet50: 1536 GPUs are about as fast as 1024 TPUs. SSD: 1024 TPUs are twice as fast as 240 GPUs. Grea…

Author of the blog post here. Cloud TPUs are designed to maximize performance-per-dollar, so you are right that pure performance comparisons at maximum scale don't tell the whole story. The most straightforward performance-per-dollar comparisons would be among several different hardware configurations across the major public clouds. However, we haven't yet seen any other public cloud MLPerf submissions at scales comp…

I cannot stand Google people's tendency to explain or sometimes rebuttal comments.

You are talking to your customers who is paying or considering paying, or in search of products.

Take the feedback, if it can be done, and it's beneficial, do it and report so.

Or stop explaining... That's simply not professional for a cloud provider...

Re: Cloud TPU Pods Break AI Training Records

#38
post #35
post #4

What's in the picture? Can't figure out the scale. Are those like server racks or breadboards or ...?

All you see is 8 server racks with colored network cables, switches and power supplies. The TPU ASICs themselves make up just a tiny part of this datacenter, you also have the printed circuit boards, cooling fins, 8x48 metal boxes, power and network cables, DC/DC or AC/DC converters at the bottom, fans or water tubes for cooling and airgaps. My startup is trying to develop wafer scale integration where you collapse 2…

> would be suprised how hard it is to get funding from them to develop it.

That's probably because there has been no evidence that wafer scale integration can actually work.

Re: Cloud TPU Pods Break AI Training Records

#39
post #19

Earlier quoted context omitted.

Author of the blog post here. Cloud TPUs are designed to maximize performance-per-dollar, so you are right that pure performance comparisons at maximum scale don't tell the whole story. The most straightforward performance-per-dollar comparisons would be among several different hardware configurations across the major public clouds. However, we haven't yet seen any other public cloud MLPerf submissions at scales comp…

Can you elaborate on the performance-per-dollar part? IE, I'm seeing GCP providing V100 at $2.48/hour and a TPUv3 at $8.00/hour

Sure. The $2.48/hour per V100 GPU on GCP does not include the price of the CPU host; that is purely the price to rent a single accelerator. By contrast, a network-attached Cloud TPU v3 device includes both a CPU host and four connected TPU v3 chips that collectively deliver up to 420 teraflops. Furthermore, each individual V100 GPU on GCP has 16 GB of memory, whereas the Cloud TPU v3 device has 128 GB of HBM.

The best apples-to-apples performance-per-dollar comparison we have publicly available was published last fall, and it compared the performance and cost of using various Cloud TPU v2 Pod slice sizes with the performance and cost of using various numbers of V100 GPUs attached to a single GCP host:

https://cloud.google.com/blog/products/ai-machine-learning/n...

We went to great lengths to ensure that we trained exactly the same version of ResNet-50 to the same accuracy in the same way across all hardware configurations. The methodology predated MLPerf and is documented in full here:

https://github.com/tensorflow/tpu/blob/master/benchmarks/Res...

If you were going to do a similar performance-per-dollar comparison today, the simplest approach might be to try to get the code from NVIDIA's MLPerf 0.6 submissions running at scale on one or more major public clouds using the fastest-available networking technology that each cloud provides:

https://github.com/mlperf/training_results_v0.6/tree/master/...

It would be very interesting to see how distributed training performance using large-scale GPU clusters in public clouds compares with the published on-premise MLPerf performance numbers using exactly the same MLPerf code and methodology. With these measurements in hand, it would then be straightforward to make performance-per-dollar comparisons with Cloud TPU v3 Pod slices of various sizes.

Re: Cloud TPU Pods Break AI Training Records

#40
post #29
post #19

Earlier quoted context omitted.

Author of the blog post here. Cloud TPUs are designed to maximize performance-per-dollar, so you are right that pure performance comparisons at maximum scale don't tell the whole story. The most straightforward performance-per-dollar comparisons would be among several different hardware configurations across the major public clouds. However, we haven't yet seen any other public cloud MLPerf submissions at scales comp…

Why performance per dollar over performance per watt? Performance per watt doesn't care where the systems are (on-prem vs cloud) and should track perf/$ (unless perf/$ is mostly determined by subsidies).

When comparing different hardware configurations within or between public clouds, power measurements generally aren't available, whereas prices or realistic price estimates generally are.
Post reply on HN