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News ARM Server CPUs

Gideon

Senior member
Nov 27, 2007
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With all the upcoming ARM servers (Let's not forget Nuvia, etc) it probably makes sense to have 1 thread from them all, instead of creating new ones for each announcement (if Not, I will rename it).

However:
Anandtech: Marwell Announces 3rd Gen Arm Server Thunder X3: 96 Cores/384 threads
ServeTheHome: Marvell ThunderX3 Arm Server CPU with 768 Threads in 2020



Could be pretty impressive, though 25% Single Threaded performance gain seems a bit meh, compared to X2, which @2.5Ghz was ~50% slower than Xeon @ 3.8Ghz

But Their marketing slides sure show potential:




 
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Hitman928

Platinum Member
Apr 15, 2012
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What all the experts think about SMT4 benefits now? :cool:
The Thunder line is strictly a server line of CPUs. There was never any doubt that SMT4 could be beneficial in many server applications. The PowerPC line already showed this. The push back against SMT4 was it being implemented in AMD CPUs that have a single architecture that covers all segments. SMT4 also tends to have some drawbacks in terms of efficiency but that's more a question of design balance than a showstopper. Marvell made some pretty bold statements when they announced ThunderX2 that didn't really pan out, so we'll see how well ThunderX3 does. On paper it looks like a much stronger competitor though it will be fighting Milan (AMD Zen 3 cores) more than Rome or anything Intel, so we'll have to wait for both to release to see how things pan out.
 
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Andrei.

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Jan 26, 2015
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What all the experts think about SMT4 benefits now? :cool:
It's completely useless in client workloads. As I explain in the article, the only gains are in data-plane workloads in which the work data is accessed at higher latency; i.e. server and cloud environments. Marvell very much said it themselves in their briefing that higher compute workloads won't see any large benefits.
 

DrMrLordX

Lifer
Apr 27, 2000
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What all the experts think about SMT4 benefits now? :cool:
Not much. They're bagging on ST performance.

edit: it's good to see that Marvell is still working on the ThunderX line. I won't deny that. They seem to be carving themselves a niche instead of trying to go head-to-head with Ampere, Huawei, and Amazon. Also where are the Huawei benchmarks? Their core is custom but should be close to A76, like Graviton2.
 

Richie Rich

Senior member
Jul 28, 2019
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It's completely useless in client workloads. As I explain in the article, the only gains are in data-plane workloads in which the work data is accessed at higher latency; i.e. server and cloud environments. Marvell very much said it themselves in their briefing that higher compute workloads won't see any large benefits.
I agree with you, SMT lowers thread performance and it's pretty clear from your Graviton2 test.
But there two very different ways how to use SMT:
  • - todays: put SMT on current core (gain +20% more throughput in cost of lower thread performance by factor 0.6x)
  • - future: merge two A76 cores without SMT into one big one with SMT2 (gain +20% through put while gaining 1.2x thread performance)

Such a core consisting of two A76 (3xALU+1xJump) would be 6xALU+2xJump wide, quite close to Apple's A13 Lightning core (4xALU+2xALU/Jump) so definitely feasible to create. IMHO shared resources can bring some nice gains in terms of efficiency. But it's definitely not easy to develop. And it doesn't make sense right know when Apple shows there is a way how to double IPC/throughput over A76.
 

amrnuke

Senior member
Apr 24, 2019
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What all the experts think about SMT4 benefits now? :cool:
Nothing new. SMT2 produces similar benefits. At best, SMT4 is offering 80% improvement over SMT1 in this application, which is not even double, despite having quadruple the therads. Also, we don't know how SMT4 compares to SMT2 in ThunderX3 chips. So you touting these benchmarks as proving SMT4 over SMT2 is curious. Can you explain what you are implying? :cool:

Some other thoughts on the release:
- They are comparing a 96 core, 384 thread part against a 64 core, 128 thread part (7742) in these comparisons. Even with 384 threads, triple that of 7742, it only manages, in the best case, to double performance, and in most cases not even that.
- We don't know what the real power consumption is. They claim a great performance per watt number, which is expected on a 96 core, 384 thread part running at lower clocks, but we will need more data on a broad number of benchmarks to make any statement about this chip.
- If AMD put out a 96 core 192 thread part, clocked it low to hit a 240W TDP, I'm guessing their performance per watt would also be great.
 

Nothingness

Platinum Member
Jul 3, 2013
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Some other thoughts on the release:
- They are comparing a 96 core, 384 thread part against a 64 core, 128 thread part (7742) in these comparisons. Even with 384 threads, triple that of 7742, it only manages, in the best case, to double performance, and in most cases not even that.
Is there a CPU with more cores/thread per socket? If not then the comparison is valid. Better performance per socket is a very good thing for a class of workloads.

- We don't know what the real power consumption is. They claim a great performance per watt number, which is expected on a 96 core, 384 thread part running at lower clocks, but we will need more data on a broad number of benchmarks to make any statement about this chip.
Agreed. And the same applies to performance, we need independent testing.

- If AMD put out a 96 core 192 thread part, clocked it low to hit a 240W TDP, I'm guessing their performance per watt would also be great.
Can they make a 96 core/192 thread chip? I guess they economically could they would as there's a market for such chips.
 
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