
Retesting AMD Ryzen Threadripper’s Game Mode: Halving Cores for More Performance - bauta-steen
http://www.anandtech.com/show/11726/retesting-amd-ryzen-threadrippers-game-mode-halving-cores-for-more-performance
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0xbear
I wonder if someone has tested it for Ryzen SIGSEGVs and hangs. I know AMD
said it's not affected, but it'd be good to see some third party confirmation
to that.

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dman
Yes its been tested by a bunch of folks at phoronix. The script that causes
issues on Ryzen has so far not caused any issues on either Epyc or
ThreadRipper.

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0xbear
That's good to know. I've been itching to put in an order.

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yarg
I thought that it disabled SMT, not the actual cores. That would make it
16c/16t not 8c/16t.

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yarg
No, I'm an idiot. It turns off one of the Zen modules, to kill the intermodule
latency.

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Filligree
That seems like it could less destructively be done by setting CPU affinities
appropriately. And, by extension, automatically through better kernel code.

Or is there more to it than that?

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microcolonel
I wonder if NT considers Threadripper a NUMA.

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yarg
So this one I actually know - Threadripper can be configured (to present) in
NUMA or UMA modes.

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sliken
Sounds like "content" mode is UMA and all cores/threads active. "Game" mode is
NUMA, but with half the CPUs disabled.

Seems like most folks with a decent OS would want NUMA and all cores/threads
active. Is that possible?

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yarg
Yes, but the software actually needs to be NUMA aware. A lot of current server
software works that way - groups of tightly coupled threads target the same
node, which prevents major performance issues in multi-CPU systems.

In general such systems are very good at multitasking, but not so good at
running a single demanding application (if it is not NUMA aware).

The same thing applies with Threadripper - albeit with lower internode
latency.

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microcolonel
I guess the next step is to make game engines and web browsers NUMA aware.

