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Intel 28-core fantasy vs. AMD 32-core reality

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Re: Intel 28-core fantasy vs. AMD 32-core reality

#111

Post by loeg »

dmichulke wrote: post #49
loeg wrote: post #36

Earlier quoted context omitted.

AMD still takes the hit for Spectre mitigations, even if it does not need Meltdown mitigation. And I'm not sure it's possible to fairly discount Intel's performance with meltdown mitigations applied. I think the impact will vary depending on workload.

> AMD still takes the hit for Spectre mitigations, even if it does not need Meltdown mitigation. That's why I wanted to keep it out of the discussion and just mentioned Meltdown, AFAIK Spectre applies to both so it would be pure speculation to identify who'll be hit harder. > And I'm not sure it's possible to fairly discount Intel's performance with meltdown mitigations applied. I think the impact will vary depending…

> That's why I wanted to keep it out of the discussion and just mentioned Meltdown, AFAIK Spectre applies to both so it would be pure speculation to identify who'll be hit harder.

That makes sense. Many people conflate the two, so I just wanted to be explicit about what I was saying :-).

> I think we have this problem already all the time (with or without mitigations applied), that's why we (should) interpret benchmarks only as a proxy.

That's totally reasonable. I think there were some discussions of the impact of the Meltdown patch (on Intel performance) on the LKML list at the time the patch(es) were being reviewed. (Other OS may have different perf impact for their Meltdown mitigations, of course, but it helps ballpark.)

Here's some discussion on anandtech, although it doesn't measure Spectre mitigations alone vs Spectre+MD; only base, MD alone, and MD+Spectre:

https://www.anandtech.com/show/12566/analyzing-meltdown-spec...

Re: Intel 28-core fantasy vs. AMD 32-core reality

#112

Post by haikuginger »

downrightmike wrote: post #44
NickNameNick wrote: post #25

Earlier quoted context omitted.

Big ditto for Oracle. probably others.

Realistically, it is easy to count cores. Some companies still count MAC addresses.

The way Oracle and VMWare bill is not bound by a technical limitation.

Re: Intel 28-core fantasy vs. AMD 32-core reality

#113

Post by orev »

This is a short term loss for Intel, but could end up being a long term win as an attack on AMD. Making this announcement forced AMD to advance their plans for the 32-core, possibly faster than they really wanted to right now. That depletes their product pipeline faster, making it more difficult to keep pace with future advances.

Edit: initial reports said that AMD was only planning to announce the 24-core CPU, and may have advanced the announcement of the 32-core chip due to Intel’a stunt. TFA doesn’t mention that, so possibly the initial reports were not accurate.

Re: Intel 28-core fantasy vs. AMD 32-core reality

#114

Post by dragontamer »

devttyeu wrote: post #86
Kubuxu wrote: post #31

Earlier quoted context omitted.

It is already the case with Thread Ripper processors. They have multiple NUMA nodes inside one socket.

It actually presents itself to the system as a single node: On a TR 1920x system: $ numactl --hardware available: 1 nodes (0) node 0 cpus: 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 node 0 size: 32107 MB node 0 free: 20738 MB node distances: node 0 0: 10

Threadripper ships in single-node interleaved memory by default, at least on my motherboard. This increases latency but doubles bandwidth (because now all 4-sticks of RAM are interleaved).

There's a BIOS setting. I personally enabled it using AMD's "Ryzen Master" program to setup NUMA mode (aka: "Local" mode in Ryzen Master).

Re: Intel 28-core fantasy vs. AMD 32-core reality

#115

Post by dragontamer »

throwaway2048 wrote: post #95
devttyeu wrote: post #86

Earlier quoted context omitted.

It actually presents itself to the system as a single node: On a TR 1920x system: $ numactl --hardware available: 1 nodes (0) node 0 cpus: 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 node 0 size: 32107 MB node 0 free: 20738 MB node distances: node 0 0: 10

windows is spectacularly poor at dealing with NUMA CPUS so threadripper is not displayed to the OS as NUMA.

Please don't say things that are obviously untrue.

I've got a Threadripper 1950x and got 2x NUMA nodes. You gotta enable a BIOS setting.

Second: "$ numactl --hardware " is a Linux command. The Windows equivalent is coreinfo.

https://docs.microsoft.com/en-us/sysinternals/downloads/core...

Re: Intel 28-core fantasy vs. AMD 32-core reality

#116

Post by dragontamer »

hardwaresofton wrote: post #103

I'm excited for what this will do to the cost of dedicated servers in ~1 year. Also, as a person who used to work at Intel, I don't know whose idea this was, but that person should probably have a long hard look at themselves -- hardware people are exactly the people that this kind of shit wouldn't fly with, because they'll almost always ask for details and can spot a hack from a mile away. On the one hand I can symp…

> I'm excited for what this will do to the cost of dedicated servers in ~1 year.

This is the opposite though?

The dedicated servers are turning into HEDTs. AMD 32-core EPYC has been available since last year, and Intel's 28-core Skylake (although $10,000) has been also available for a year.

So dedicated servers got this tech first, then HEDT got it a bit later. I guess Threadripper is Zen+ so its technically HEDT gets the 12nm tech first, but the 32-core infrastructure was in EPYC first.

Re: Intel 28-core fantasy vs. AMD 32-core reality

#117

Post by dragontamer »

loeg wrote: post #33
examancer wrote: post #28

Earlier quoted context omitted.

That's literally what the OP did. A 1950X is only $799 now, so less than half a top end i9.

That's extremely recent. It was more like $900 a day or two ago: https://camelcamelcamel.com/AMD-Threadripper-32-thread-Proce... And it is still $960 on Newegg: https://www.newegg.com/Product/Product.aspx?Item=N82E1681911...

I got my 1950x for $699 a few months ago. Its been $699 for a while at Microcenter.

The "price-competitive" i9-7900x is 10-cores for $799, and seems to be the best price-competitive comparison. Better single-thread, better at AVX512 tasks, but weaker in general purpose multithreading due to having fewer cores.

Re: Intel 28-core fantasy vs. AMD 32-core reality

#118

Post by craftyguy »

esturk wrote: post #110
jacob019 wrote: post #107

Earlier quoted context omitted.

Unfortunately it might work. With today's news cycles, an average consumer may have noticed the headline about Intel's 5GHz 28-core monster, and that's it. Follow up articles aren't as interesting.

The average consumer may just buy a smartphone over a PC. The average tech savvy consumer may just build the PC over buying off the shelf ones. In either case most people won't be buying these 28 core chips unless they are reps for enterprises in which case they will most definitely have done their HW before buying this.

>reps for enterprises in which case they will most definitely have done their HW before buying this.

Don't assume they would. Plenty of purchasing in large companies is associated with some higher up hearing about something, wanting it, then buying it to 'help' in some obscure way.

Re: Intel 28-core fantasy vs. AMD 32-core reality

#119

Post by dragontamer »

rocky1138 wrote: post #77
robin_reala wrote: post #27

Earlier quoted context omitted.

Are you talking about contributions to OSS in general, or specifically around processors?

In general, as a company.

Both AMD and Intel seem highly supportive of OSS.

Intel's iGPUs had the best Linux drivers for the longest time, while AMD just managed to mainline their GPU drivers into the 4.15 kernel.

I think AMD is "worse" at it but for understandable reasons. They're a smaller company, so it takes a bit longer for AMD to release low-level manuals. (Ex: still waiting on those Zen architecture instruction timings AMD!!). Even then, AMD releases "draft" manuals which allow the OSS world to move. So the important stuff is still out there, even as AMD is a bit slow on the documentation front.

Basically, Intel is a bigger company and handles the details a bit better than AMD. But both are highly supportive of OSS in great degrees.

Re: Intel 28-core fantasy vs. AMD 32-core reality

#120

Post by dragontamer »

theandrewbailey wrote: post #99
CoolGuySteve wrote: post #38

Earlier quoted context omitted.

Ryzen chips scale in performance more than Intel when you overclock the RAM. Some part of the chip cache is more tightly coupled to the RAM latency, and my rampant speculation is that Intel doesn’t really care about memory bandwidth as much on the desktop anyways.

Ryzen CPUs divide the cores into two "core complexes" that communicate over a bus called infinity fabric. Probably to make the engineering easier, the memory controller and RAM speed is the same as the infinity fabric's speed. You'll get good gains up to 3000 MHz, less so with more. https://www.anandtech.com/show/11857/memory-scaling-on-ryzen... http://www.legitreviews.com/ddr4-memory-scaling-amd-am4-plat...

And the only thing I'll add is that "infinity fabric" is a singular clock-domain across all dies. So in Ryzen, its not a big deal cause there's only one die.

But in Threadripper (2-dies) or EPYC (4-dies), the "infinity fabric" bus is what connects the CPUs and Memory-controllers together.

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