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Comment by emn13 | Hacker News Reader

Although given the relative performance, I can't imagine who'd pick the arm option currently, unless the pricing difference is truly extreme. There's just too many downsides to arm servers at this time: it's not just total overall performance, but particuarly single threaded performance (which affects e.g. latency that your readers experience), power usage (affects costs), and of course availability of software.

It's getting close, that's for sure - and there may well be some niche where it already makes sense, but I wouldn't know which one.

Probably the best value proposition is that the gap is likely to shrink, and investing now may help you prepare for a future switch when it makes more sense.

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> It's getting close, that's for sure - and there may well be some niche where it already makes sense, but I wouldn't know which one.

Proprietary blobs such as Intel's ME that cannot be removed from Intel Xeon systems pose a security risk. If the ARM systems are found to lack them and they achieve the status of being good enough, security minded individuals and organizations will buy them because of that.

As long as that happens, Cavium will be able to use the revenues to develop the next generation of chips to better compete on traditional metrics like Intel was able to do against the RISC vendors of the past. As a security minded individual myself, I am well aware of that and I look forward to supporting such developments by purchasing such hardware for applications where it can be used.

There are others thinking this too. Some of them are watching the Talos workstation motherboard come to market with that in mind. The people behind it are even talking about IBM's executives being willing to make the POWER9 processor's microcode open source if the POWER8 model succeeds.

https://www.raptorengineering.com/TALOS/prerelease.php

"Proprietary blobs such as Intel's ME that cannot be removed from Intel Xeon systems pose a security risk. If the ARM systems are found to lack them and they achieve the status of being good enough, security minded individuals and organizations will buy them because of that."

Do you expect the above to be anything more than a rounding error of the total server market? I doubt Cavium is going to finance its development from that.

If you want it to be so, then make it so. There's plenty of ammunition to use in all of the leaks.

> ThunderX2 is a 14nm FinFET design, and the company claims it will deliver 2 to 3 times the performance of ThunderX on select workloads with a higher performance to power ratio. Their plan for the X2 is to include 54 ARMv8.2 cores with a target frequency of 2.4 to 2.8 GHz and up to 3 GHz in turbo mode (versus their current 28nm, 48 core, 2.5GHz design), 32MB of what Cavium calls shared Last Level Cache (LLC), 6 DDR4 memory interfaces running at 3200MHz (1 DPC) or 2966MHz (2 DPC), multiple 10/25/40/100 Gb/s Ethernet (KR) interfaces, enhanced virtualization support (including IO), ARM Holdings Trustzone security and a variety of hardware accelerators. [...] [1]

Is ARM's TrustZone not the same as Intel's ME? At least I remember that AMD uses a ARM Core with TrustZone in it's x86 CPU's to basically achieve the same (or something similar) as Intel's Management Engine.

[1] quoted from: http://www.forbes.com/sites/moorinsights/2016/05/30/cavium-s...

TrustZone is basically the name for the ring -1/hypervisor access level for ARM CPUs, not a separate "engine" or product. It can be used to run and isolate code at a higher privilege level than an operating system eg. for DRM.

> Although given the relative performance,

AFAICT the benchmarks seem to focus on traditional use cases like CPU-bound/memory-bound computation. But the ever-growing use case is the physical hardware that underlies the commercial "cloud computing" focus. IMO much of that market is running I/O-bound code and if I were sourcing hardware for one of those providers I would want to offer a tier which could serve enormous numbers of clients on a single node.

Power consumption is another huge element of data center costs and scaling up ARM-based servers is likely to reap a big savings.

In my experience, many I/O bound applications tend to benefit less from parallelism, but still usually benefit from a fast (single threaded) core - there's often still quite a bit of cpu processing in supposedly I/O bound tasks. As in: you're still better off getting a fast CPU, you just don't need a bazillion cores. Since perf/watt is still poorer in general on ARM cores you'd need to be very very sure that you really don't need any CPU for that to be worth it.

Also; most of these CPU's aren't designed in a vacuum: faster CPUs tend to have better I/O subsystems. E.g. memory latency (which is I/O from a CPU's perspective) is much, much worse on ARM, probably because it hasn't historically mattered as much.

So I'd expect arm to make sense on special purpose I/O related stuff, where you can be sure the limitations aren't an issue. Do some fast e.g. SSDs include ARM chips?

Perhaps

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