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AMD Ryzen Threadripper 3000 32-core CPU is more bad news for Intel

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Re: AMD Ryzen Threadripper 3000 32-core CPU is more bad news for Intel

#31

Post by semi-extrinsic »

3JPLW wrote: post #12
Jonnax wrote: post #3

Earlier quoted context omitted.

I hear a lot about AVX-512 being really good. Is there any software that's commonly used that has a measurable performance boost with it? Or is it more specialised stuff?

One challenge with AVX-512 is that it can actually _slow down_ your code. It's so power hungry that if you're using it on more than one core it almost immediately incurs significant throttling. Now, if everything you're doing is 512 bits at a time, you're still winning. But if you're interleaving scalar and vector arithmetic, the drop in clock speeds could slow down the scalar code quite substantially. https://blog.c…

How fast does the CPU step up and down the throttling caused by AVX-512?

Basically, if you are interleaving like you suggest, does the processor detect this and reduce the throttling by the "duty cycle" of 512-bit operations?

If not, could there be a way to tell the CPU to do this?

Re: AMD Ryzen Threadripper 3000 32-core CPU is more bad news for Intel

#32

Post by rbanffy »

astrodust wrote: post #17
GiorgioG wrote: post #14

I have the original Threadripper 1950X overclocked to 4.1ghz and I’ve been pretty happy with it. As a developer I can’t find much reason to upgrade 2 years after its release. Single core improvements (from AMD or Intel) aren’t game-changing. More cores won’t do anything for me (.NET Core, angular, etc) I’ve considered switching back to intel for their 5ghz processors but based on benchmarks, I wouldn’t see anything b…

If you ever get into Docker/Kubernetes, being able to spin up a local cluster for testing is a pretty big deal. Having that running in the background and not impacting your usual workload is huge. I've been testing a Kubernetes cluster built on 32-core AMD servers and it's unreal the workloads you can throw at them. I'm used to 4 or 8-core Xeon chips and this is a whole different game.

That's true, but memory/IO is a much bigger issue in this scenario than processing power. While running a cluster in VMs, I'm frequently limited by IO (and if your VMs use more memory than it's physically available, you'll quickly descent into swap hell) well before my CPUs register a significant uptick in usage.

And, mind you, my workstation is 4 year old Xeon with 64 gigs of memory and reasonably fast (but not amazing) SATA SSD.

On a side note, I work more and more from a couple of i3 and i5 laptops and only use the workstation to do heavy lifting tasks, such as replicating these more exotic setups.

Re: AMD Ryzen Threadripper 3000 32-core CPU is more bad news for Intel

#33

Post by rbanffy »

dragontamer wrote: post #25
Symmetry wrote: post #2

AMD is in a really good position right now. Intel still has the lead in low idle power which is good in laptops. Ryzen lets different cores have different max frequencies so if your code is single threaded and your operating system isn't the newest that could be a reason to go Intel. Likewise if its single threaded and can take advantage of AVX-512 or the Intel Math Kernel Library. But otherwise?

The main selling point for Intel isn't speed anymore. Intel still has superior performance counters and debugging features. Mozilla's rr (Record and Replay framework) only works on Intel for example, and Intel vTune is a very good tool. AVX512 is also an advantage, as you've noted. There are other instruction set advantages: I think Intel has faster division / modulus operator, and also has single-clock pext / pdep (…

Even if you do, in most cases you won't use them on all your workloads. This means not all your boxes need to be Intel.

Re: AMD Ryzen Threadripper 3000 32-core CPU is more bad news for Intel

#34

Post by rbanffy »

ses1984 wrote: post #15
GiorgioG wrote: post #14

I have the original Threadripper 1950X overclocked to 4.1ghz and I’ve been pretty happy with it. As a developer I can’t find much reason to upgrade 2 years after its release. Single core improvements (from AMD or Intel) aren’t game-changing. More cores won’t do anything for me (.NET Core, angular, etc) I’ve considered switching back to intel for their 5ghz processors but based on benchmarks, I wouldn’t see anything b…

I can still put more cores to work, compiling stuff. I have a 6 core quad channel intel and I've been waiting for this threadripper to come out.

Maybe, but how often do people compile their software?

Re: AMD Ryzen Threadripper 3000 32-core CPU is more bad news for Intel

#35

Post by robocat »

3JPLW wrote: post #12
Jonnax wrote: post #3

Earlier quoted context omitted.

I hear a lot about AVX-512 being really good. Is there any software that's commonly used that has a measurable performance boost with it? Or is it more specialised stuff?

One challenge with AVX-512 is that it can actually _slow down_ your code. It's so power hungry that if you're using it on more than one core it almost immediately incurs significant throttling. Now, if everything you're doing is 512 bits at a time, you're still winning. But if you're interleaving scalar and vector arithmetic, the drop in clock speeds could slow down the scalar code quite substantially. https://blog.c…

Also see https://lemire.me/blog/2018/09/07/avx-512-when-and-how-to-us...

* The processor does not immediately downclock when encountering heavy AVX512 instructions: it will first execute these instructions with reduced performance (say 4x slower) and only when there are many of them will the processor change its frequency. Light 512-bit instructions will move the core to a slightly lower clock. * Downclocking is per core and for a short time after you have used particular instructions (e.g., ~2ms). * The downclocking of a core is based on: the current license level of that core, and also the total number of active cores on the same CPU socket (irrespective of the license level of the other cores).

Re: AMD Ryzen Threadripper 3000 32-core CPU is more bad news for Intel

#36

Post by rbanffy »

guelo wrote: post #4

Why is AMD making these chips with 14nm transistors instead of using TSMC's 7nm stuff? AMD is only catching up to Intel because Intel's 10nm has been delayed so much, but if Intel can ever figure out their 10nm process they'll be in the lead again.

As a fun fact, IBM's newest (and quite impressive) mainframe, the z15, is still using the same Global Foundries 14nm process the z14 did. The next generation (including POWER10) will probably be 7nm, but not come from GF.

It runs above 5 GHz.

Re: AMD Ryzen Threadripper 3000 32-core CPU is more bad news for Intel

#37

Post by ses1984 »

rbanffy wrote: post #34
ses1984 wrote: post #15

Earlier quoted context omitted.

I can still put more cores to work, compiling stuff. I have a 6 core quad channel intel and I've been waiting for this threadripper to come out.

Maybe, but how often do people compile their software?

If you're editing it, a lot.

Re: AMD Ryzen Threadripper 3000 32-core CPU is more bad news for Intel

#38

Post by kraig911 »

Now if only programming multi-core work could catch up to this hardware. Honestly chips with more cores is starting to sound like cars with more wheels or I guess more valves lately.

Doesn't matter the horsepower the speed limit is the same until we can make software better.

Re: AMD Ryzen Threadripper 3000 32-core CPU is more bad news for Intel

#39

Post by pkaye »

Jonnax wrote: post #3
Symmetry wrote: post #2

AMD is in a really good position right now. Intel still has the lead in low idle power which is good in laptops. Ryzen lets different cores have different max frequencies so if your code is single threaded and your operating system isn't the newest that could be a reason to go Intel. Likewise if its single threaded and can take advantage of AVX-512 or the Intel Math Kernel Library. But otherwise?

I hear a lot about AVX-512 being really good. Is there any software that's commonly used that has a measurable performance boost with it? Or is it more specialised stuff?

I've used it once but on Intel the clock is throttled with AVX-512 so the overall program performance improved only 1% because the non-SIMD code was running at a slower clock.

Re: AMD Ryzen Threadripper 3000 32-core CPU is more bad news for Intel

#40

Post by brianobush »

kraig911 wrote: post #38

Now if only programming multi-core work could catch up to this hardware. Honestly chips with more cores is starting to sound like cars with more wheels or I guess more valves lately. Doesn't matter the horsepower the speed limit is the same until we can make software better.

Depends on the problem domain. Some problems/algorithms, like genetic algorithms, are simple to implement on multicore systems with thread pools with significant gains in overall performance.
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