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The Ampere Altra Review: 2x 80 Cores Arm Server Performance Monster

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Re: The Ampere Altra Review: 2x 80 Cores Arm Server Performance Monster

#231

Post by saagarjha »

emn13 wrote: post #166
jeffbee wrote: post #109

Earlier quoted context omitted.

Yes but they were terrible. Just being ARM isn't some kind of magic dust. It has to actually be fast.

If you look at the historical benchmarks of the non-apple ARM chips, though they're clearly behind apple, they have largely kept pace. Huawei was perhaps even closing the gap before the trade war knocked them out of contention. I don't think apple was really all that special in this regard. They were ahead of the curve, which is impressive, but the market was created by arm, not just apple. I doubt we'd be seeing thi…

They really haven't–Apple has slowly gained on, then outpaced them over the last several years. Apple's chips these days "lap" others, where the best that competitors have to offer perform poorer than last year's design.

Re: The Ampere Altra Review: 2x 80 Cores Arm Server Performance Monster

#232

Post by coder543 »

dragontamer wrote: post #228
coder543 wrote: post #224

Earlier quoted context omitted.

Preface: If you have actually encountered applications that must be run on 8-socket systems because those are literally the only fit for the application... I would love to hear about those experiences. With the advent of Epyc Rome, most use cases for these 8-socket systems vanished instantly. It would be fascinating to hear about use cases that still exist. Your experiences are obviously different than mine. If you n…

I mean, I buy AMD Threadripper for my home use and experimentation. I'm pretty aware of the benefits of AMD's architecture. But I also know that in-memory databases are a thing. Nothing I've touched personally needs an in-memory database, but its a real solution to a real problem. A niche for sure, but a niche that's pretty common actually. Whenever I see these absurd 8-socket designs with 48TBs of RAM, I instinctive…

> its not that hard to imagine why 48TBs of RAM beats out any other architecture (including Optane or Flash).

Agree to disagree.

In-memory databases are common yes, but it is pretty hard to imagine practical situations where an in-memory database can't handle a few nanoseconds of additional latency.

All else being equal, of course more RAM is nice to have. All else is not equal, though, so this is all highly theoretical.

But it is fun to think about!

Re: The Ampere Altra Review: 2x 80 Cores Arm Server Performance Monster

#233

Post by dragontamer »

coder543 wrote: post #230
dragontamer wrote: post #221

Earlier quoted context omitted.

> If the application is relying heavily on the NUMA interconnect to transfer tons of data, it's not going to be making efficient use of the processor cores or the memory bandwidth. It's a total all around bust. You're just wasting money at that point. If the interconnect is your bottleneck, you spend money on the interconnect to make it faster. Basic engineering: you attack the bottleneck. You don't start talking abo…

You have since edited your comment, so... > That's not even that hard to figure out! A 48TB Memcached / Redis, which is far more useful than a 8TB Memcached / Redis box. No... dozens of terabytes of Optane would be just as good and much much cheaper. The person designing the system would have to prove that a few nanoseconds of latency difference makes any material difference to the company's profits in order to justi…

> No... dozens of terabytes of Optane would be just as good and much much cheaper.

PCIe Optane is orders of magnitudes slower than DDR4. In both bandwidth and latency.

The only Optane that keeps up to DDR4 (kinda-sorta) is the Optane DIMMs which are exclusive to Xeon Golds / Platinum systems.

Re: The Ampere Altra Review: 2x 80 Cores Arm Server Performance Monster

#234

Post by saagarjha »

flyinghamster wrote: post #66
my123 wrote: post #62

Earlier quoted context omitted.

Windows on arm64 systems aren't locked down. Meanwhile for arm64 Macs, they aren't either. Yesterday, https://twitter.com/xenokovah/status/1339914714055368704?s=2... was released to run unsigned kernels.

It's encouraging to see an effort like this, but unless it can become a first-class citizen on M1 hardware, it will be at best like trying to keep an iDevice jailbroken, or having a custom Android ROM that lacks important basic functionality like VoLTE. One can hope, I guess. If I could be sure I could run Linux without it being hobbled, and that Apple wouldn't pull the rug out from under me, I could actually see mys…

Not quite, since Apple actively works against jailbreaks on iOS. On macOS they have provided an actual path for code execution to boot alternate OSes.

Re: The Ampere Altra Review: 2x 80 Cores Arm Server Performance Monster

#235

Post by saagarjha »

strenholme wrote: post #214
mtgx wrote: post #8

Earlier quoted context omitted.

If I were them I wouldn't even bother with anything pre-Arm v9. That's going to draw all the hype, especially when Apple announces the Arm v9-based M2 next year. And then I'm sure most sheep-like OEMs will say "Oh, we want THAT, too. Where is it - we want it yesterday!" But AMD won't be able to provide one too soon, because they would've gone all in on Arm v8, and they'd want to squeeze at least a couple of generatio…

The problem is that ARMv9, as I type this, is not available . Perhaps ARM holdings and/or NVidia are working on the ARMv9 instruction set, and there has been a lot of speculation about what ARMv9 will be, but so far nothing concrete. [1] ARMv8 (i.e. 64-bit ARM), of course, has been around for a while now. [1] Keep in mind that anything on Reddit not confirmed elsewhere is very likely either wild speculation or made u…

Apple is usually the first to ship ARM designs. I think they are the only ARMv8.5 implementation at the moment.

Re: The Ampere Altra Review: 2x 80 Cores Arm Server Performance Monster

#236

Post by coder543 »

dragontamer wrote: post #233
coder543 wrote: post #230

Earlier quoted context omitted.

You have since edited your comment, so... > That's not even that hard to figure out! A 48TB Memcached / Redis, which is far more useful than a 8TB Memcached / Redis box. No... dozens of terabytes of Optane would be just as good and much much cheaper. The person designing the system would have to prove that a few nanoseconds of latency difference makes any material difference to the company's profits in order to justi…

> No... dozens of terabytes of Optane would be just as good and much much cheaper. PCIe Optane is orders of magnitudes slower than DDR4. In both bandwidth and latency. The only Optane that keeps up to DDR4 (kinda-sorta) is the Optane DIMMs which are exclusive to Xeon Golds / Platinum systems.

Not really... especially if this is an in-memory database attached to a network, as implied.

It’s only slower if someone can observe the difference, which I don’t think they would be able to in this design.

I’m a strong proponent of using fewer, larger machines and services, instead of incurring the overhead involved in spreading things out into a million microservices on a million machines. But there is a balance to be achieved, and beyond a certain point... synthetic improvements in performance don’t show up in the real world.

Queuing up a few database requests concurrently to make up for the overhead of literally hundreds of nanoseconds of latency is trivial, especially when Optane can service those requests concurrently, unlike a spinning hard drive. Applications running on other machines won’t be able to tell a difference.

But, agree to disagree.

There are probably applications where these mega machines are useful, but I don’t personally find this to be a compelling example.

I readily admit that I could be wrong... but neither of us have numbers in front of us showing a compelling reason for a company to spend unbelievable amounts of money on a single machine. My experiences (limited compared to many, I’m sure) tell me this isn’t the winning scenario, though.

Re: The Ampere Altra Review: 2x 80 Cores Arm Server Performance Monster

#237

Post by dragontamer »

coder543 wrote: post #236
dragontamer wrote: post #233

Earlier quoted context omitted.

> No... dozens of terabytes of Optane would be just as good and much much cheaper. PCIe Optane is orders of magnitudes slower than DDR4. In both bandwidth and latency. The only Optane that keeps up to DDR4 (kinda-sorta) is the Optane DIMMs which are exclusive to Xeon Golds / Platinum systems.

Not really... especially if this is an in-memory database attached to a network, as implied. It’s only slower if someone can observe the difference, which I don’t think they would be able to in this design. I’m a strong proponent of using fewer, larger machines and services, instead of incurring the overhead involved in spreading things out into a million microservices on a million machines. But there is a balance to…

> I readily admit that I could be wrong... but neither of us have numbers in front of us showing a compelling reason for a company to spend unbelievable amounts of money on a single machine.

$500k on a machine isn't a lot of money compared to engineers. Even if you buy 4 of them for test / staging / 2xProduction, its not a lot compared to the amount spent on programming.

Re: The Ampere Altra Review: 2x 80 Cores Arm Server Performance Monster

#238

Post by coder543 »

dragontamer wrote: post #237
coder543 wrote: post #236

Earlier quoted context omitted.

Not really... especially if this is an in-memory database attached to a network, as implied. It’s only slower if someone can observe the difference, which I don’t think they would be able to in this design. I’m a strong proponent of using fewer, larger machines and services, instead of incurring the overhead involved in spreading things out into a million microservices on a million machines. But there is a balance to…

> I readily admit that I could be wrong... but neither of us have numbers in front of us showing a compelling reason for a company to spend unbelievable amounts of money on a single machine. $500k on a machine isn't a lot of money compared to engineers. Even if you buy 4 of them for test / staging / 2xProduction, its not a lot compared to the amount spent on programming.

One thing being expensive doesn’t make another thing not expensive.

It’s possible for them to both be independently expensive, and I’m saying that unless you can prove that the performance difference makes any difference to company profits, it is literally a huge waste of company money to buy those expensive machines.

A lot of applications will actually perform worse in NUMA environments, so you’re spending more money to get worse performance.

Reality isn’t as simple as “throw unlimited money at Intel to save engineering time.” Intel wishes it was.

Engineering effort will be expended either way. It is worth finding the right solution, rather than the most expensive solution. Especially since that most expensive solution is likely to come with major problems.

Re: The Ampere Altra Review: 2x 80 Cores Arm Server Performance Monster

#239

Post by kllrnohj »

klelatti wrote: post #219
kllrnohj wrote: post #204

Earlier quoted context omitted.

> AMD should see the writing on the wall and start designing ARM CPUs. ARM's brand new 80-core system struggles to match AMD's year old 64-core system, while also being entirely unable to run some of the workloads either at all or in the 2S configuration. And with mostly comparable power draw and a much worse turbo story that ARM is trying to pretend is somehow a good thing. Competition is great, but it's a bit prema…

It's not Arm's system it's Ampere's. Arm is claiming nothing about this cpu.

This system uses ARM's Neoverse-N1 CPU cores. Ampere put it in a socket, but it's still "ARM's" CPU core. This isn't a custom design like Apple's CPUs.

And per the article it sounds like it's ARM's fault this can't exceed 3.3 ghz. That seems to be a Neoverse-N1 limitation:

"Fundamentally, the Altra’s handling of frequency and power in such a manner is simply a by-product of the Neoverse-N1 cores not being able to clock in higher than 3.3GHz"

Re: The Ampere Altra Review: 2x 80 Cores Arm Server Performance Monster

#240

Post by kllrnohj »

foobarian wrote: post #205
avianlyric wrote: post #200

Earlier quoted context omitted.

> I'm also curious if there is something inherent to ARM that would stop them from making similar optimizations to the AMD chips. Yeah ARM isn’t x86. Apple made big gains by leveraging the difference in instruction length and complexity between x86 and ARM. Something AMD can’t do, and they’ve said as much.

I still don't have a clear understanding. Apple also made big gains by integrating performance sensitive stuff on the package. AMD could do the same. I wonder if they are constrained by some hardware-level interoperability requirements across the motherboard, like with chipsets or DMA controllers or whatnot made by different companies. Apple clearly has a nice advantage here.

> Apple also made big gains by integrating performance sensitive stuff on the package. AMD could do the same.

The only thing the M1 has integrated that a typical AMD or Intel laptop CPU doesn't have is a neural net processor. Everything else about the M1's 'integrated architecture' is typical.

Notably the M1's RAM is not integrated as is often incorrectly stated. It's just regular soldered LPDDR4X. And M1's RAM latencies are worse than Intel & AMD's socketed DDR4 latencies, so being soldered and physically close is definitely not providing a performance advantage.

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