Cost Analysis - An x86 Massacre

The Graviton2 showcased that it can keep up extremely well in terms of performance and throughput, even beating the competition in a lot of the tests. However sometimes you don’t care too much about performance, and you just want to get some workload completed in the cheapest way possible, at which point value comes into play.

Amazon does allude to that, stating that the new chip is able to achieve 40% better performance per dollar than its competition. As covered in the introduction, for the 64-vCPU count 16xlarge instances the m6g (Graviton2), m5a (EPYC1), and m5n (Xeon Cascade Lake) are priced at an hourly cost of $2.464, $2.752 and $3.808 respectively.

Translating the time to completion of our various SPEC tests to hours and multiplying by the hourly cost, we end up with a cost per fixed workload metric:

An aggregate of all workloads summed up together, which should hopefully end up in a representative figure for a wide variety of real-world use-cases, we do end up seeing the Graviton2 coming in 40% cheaper than the competing platforms, an outstanding figure.

If we were to compare the same fixed workload at smaller instance counts, because of Graviton2’s better per-thread performance, we’re seeing even better results on 4xlarge (16 vCPUs) instances. Here the Amazon chip showcases 43% better value than the Xeon chip, and beats the AMD instances by being 53% cheaper.

If we were to transform the results into a fixed throughput per dollar metric, we again see the Graviton2 far ahead. The unit here is SPEC runs per dollar.

The lower the vCPU instance size, the better value the Graviton2 seemingly becomes, as its performance with increased vCPUs scales sublinearly, but the cost of bigger vCPU instances scales linearly, an effect that’s almost not present at all in the AMD system, and only marginally present in the Xeon instances.

Again, the Graviton2’s scaling here might differ in production instances, but given that you can’t just chop off half the chip (or have access to only one of two sockets, in Intel’s case here) and that Amazon seemingly isn’t doing any static partitioning of the chip’s shared resources, I do think it’s more likely than not that such performance and value figures will be encountered in the real-world.

Even ignoring the lower vCPU instances, Amazon was able to deliver on its promise of 40% better performance per dollar, and it’s a massive shakeup for the AWS and EC2 ecosystem.

SPEC - MT Performance (4xlarge 16 vCPU) Conclusion & End Remarks
POST A COMMENT

95 Comments

View All Comments

  • Wilco1 - Friday, March 13, 2020 - link

    Developing a chip based on a standard Arm core is much cheaper. Arm chip volumes are much higher than Intel and AMD, the costs are spread out over billions of chips. Reply
  • ksec - Tuesday, March 10, 2020 - link

    ARM's licensing comparatively speaking is extremely cheap even for their most expensive N1 Core Blueprint. The development and production cost are largely on ARM's because of the platform model. So Amazon is only really paying for the cost to Fab with TSMC, I would be surprised if those chip cost more than $300. Which is at least a few thousand less than Intel or even AMD.

    Amazon will have to paid for all the software cost though. Making sure all their tools, and software runs on ARM. That is very expensive in engineering cost, but paid off in long term.
    Reply
  • extide - Friday, March 13, 2020 - link

    Actual production cost is going to be more like $50 or so. WAY less than $300. Reply
  • ksec - Monday, March 30, 2020 - link

    Only the Wafer Cost alone would be $50+ assuming 100% yield. That is excluding licensing and additional R&D. At their volume I would not be surprised it stack up to $300 Reply
  • FunBunny2 - Tuesday, March 10, 2020 - link

    "Vertical integration is powerful."

    I find it amusing that compute folks are reinventing the wheel from Henry Ford!! River Rouge.
    Reply
  • mrvco - Tuesday, March 10, 2020 - link

    It would be interesting to see how the AWS instances compare to performance-competitive Azure instances on a value basis. Reply
  • kliend - Tuesday, March 10, 2020 - link

    Anecdotally, Yes. Amazon is always trying to bring in users for little/no immediate profit. Reply
  • skaurus - Tuesday, March 10, 2020 - link

    At scale, predictability is more important in infrastructure than cost. It may seem that if we have everything we need compiled for Arm, we can just switch over. But these things often look easier in theory than practice. I'd be wary to move existing service to Arm instances, or even starting a new one when I just want to iterate fast and just be sure that underlying level doesn't have any new surprises.
    It will be fine If I have time to experiment, or later, when the dust settles. Right now, I doubt that switching over to these instances once they are available, is actually easy or even smart decision.
    Reply
  • FunBunny2 - Tuesday, March 10, 2020 - link

    "It may seem that if we have everything we need compiled for Arm, we can just switch over. But these things often look easier in theory than practice. "

    with language compliant compilers, I don't buy that argument. it can certainly be true that RISC-ier processors yield larger binaries and slower performance, but real application failure has to be due to OS mismatches. C is the universal assembler.
    Reply
  • mm0zct - Wednesday, March 11, 2020 - link

    Beware that in C struct packing is ABI dependent, if you write out a struct to disk on x86_64, and try and read it back in on Aarch64, you might have a bad time unless you use the packed pragma and use specified-width types. This is the sort of thing that might get you if you try to migrate between architectures.

    Also many languages (including C) have hand optimised math libraries with inline assembler, which might still be using plain-C fallbacks on other architectures. There was a good article discussing the migration to Aarch64 at Cloudflare, they particulary encountered issues with go not being optimised on Aarch64 yet https://blog.cloudflare.com/arm-takes-wing/
    Reply

Log in

Don't have an account? Sign up now