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Re: 128-core AMD server

Posted: Sat Nov 25, 2017 9:56 pm
by Leo
jdart wrote:Some benchmarks (Stockfish 8, 16G hash):

32-core dual Opteron (2xOpteron 6376, 1/4 of the AMD server box, Linux):
26.3M nps

24-core dual Opteron (2xOpteron 6344, Linux):
21.8M nps

dual Xeon 2670 (16 cores, Linux):
24.0M nps

i7-6900k (8 cores, Windows):
14.08M nps
What about the argument that its time to depth that matters?

Re: 128-core AMD server

Posted: Sat Nov 25, 2017 9:59 pm
by Leo
jdart wrote:Rates in my area ramp up with usage and I have once in a while hit their "super overcharge now we're really serious" rate level, whatever they actually call it.

I am planning to get solar panels on the house next year.

--Jon
I have a 15 amp breaker that kept tripping. It was hot to the touch. I now have to wait until I can hook up the computer to 20 amps.

Re: 128-core AMD server

Posted: Sat Nov 25, 2017 10:20 pm
by jhellis3
What about the argument that its time to depth that matters?
TTD is a useless measurement for LazySMP.

Re: 128-core AMD server

Posted: Sun Nov 26, 2017 12:12 am
by Adam Hair
Leo wrote:
jdart wrote:Rates in my area ramp up with usage and I have once in a while hit their "super overcharge now we're really serious" rate level, whatever they actually call it.

I am planning to get solar panels on the house next year.

--Jon
I have a 15 amp breaker that kept tripping. It was hot to the touch. I now have to wait until I can hook up the computer to 20 amps.
Have your electrician check for a loose connection also. There could be a problem where the wire connects to the circuit breaker (small possibility) or where the circuit breaker plugs onto the electrical panel busbar (greater possibility). It is doubtful that you have a large enough overcurrent to cause the circuit breaker to be hot to the touch.

My guess is that the connection between the breaker and busbar is failing.

Re: 128-core AMD server

Posted: Sun Nov 26, 2017 1:48 am
by Leo
I have read over and over that a powerful 8-16 core machine will defeat a 32-64 core machine. After 16 to 20 cores it scales very badly. Has something changed or is this still true?

Re: 128-core AMD server

Posted: Sun Nov 26, 2017 1:50 am
by Leo
Adam Hair wrote:
Leo wrote:
jdart wrote:Rates in my area ramp up with usage and I have once in a while hit their "super overcharge now we're really serious" rate level, whatever they actually call it.

I am planning to get solar panels on the house next year.

--Jon
I have a 15 amp breaker that kept tripping. It was hot to the touch. I now have to wait until I can hook up the computer to 20 amps.
Have your electrician check for a loose connection also. There could be a problem where the wire connects to the circuit breaker (small possibility) or where the circuit breaker plugs onto the electrical panel busbar (greater possibility). It is doubtful that you have a large enough overcurrent to cause the circuit breaker to be hot to the touch.

My guess is that the connection between the breaker and busbar is failing.
Thanks for the info.

Re: 128-core AMD server

Posted: Sun Nov 26, 2017 3:52 am
by jhellis3
I have read over and over that a powerful 8-16 core machine will defeat a 32-64 core machine. After 16 to 20 cores it scales very badly. Has something changed or is this still true?
It was never true? This has more to do with clock speed, heat generation, and power consumption than any sort of scaling issue.

Generally, the more cores per chip the lower the base and boost clocks because you can only dissipate so much heat per mm^2, unless you want to move to water cooling or something more exotic.

But the idea that more cores are somehow inherently bad is just bullshit. Are there diminishing returns, yes. Does performance per dollar drop drastically, yes. But more nodes searched at higher depths will always be better than nothing (provided equal clocks).

Re: 128-core AMD server

Posted: Sun Nov 26, 2017 9:42 pm
by jwes
jhellis3 wrote:
What about the argument that its time to depth that matters?
TTD is a useless measurement for LazySMP.
So you're saying that LazySMP finds better moves at equal depths rather than finding the same move faster.

Re: 128-core AMD server

Posted: Mon Nov 27, 2017 12:36 am
by jdart
Arasan scales quite badly on 32 cores, at present. It is on my to-do list to look at soon.

But other engines do better: Stockfish for example.

Crafty also uses multiple cores efficiently and can hits amazingly high NPS, but I haven't tried it on this 32 core box.

--Jon

Re: 128-core AMD server

Posted: Tue Nov 28, 2017 3:55 am
by Dann Corbit
jdart wrote:Arasan scales quite badly on 32 cores, at present. It is on my to-do list to look at soon.

But other engines do better: Stockfish for example.

Crafty also uses multiple cores efficiently and can hits amazingly high NPS, but I haven't tried it on this 32 core box.

--Jon
Texel scales brilliantly