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Retesting AMD Ryzen Threadripper’s Game Mode: Halving Cores for More Performance
- yarg 9y agoI thought that it disabled SMT, not the actual cores. That would make it 16c/16t not 8c/16t.
- yarg 9y agoNo, I'm an idiot. It turns off one of the Zen modules, to kill the intermodule latency.
- Filligree 9y agoThat 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?
- microcolonel 9y agoI wonder if NT considers Threadripper a NUMA.
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- snuxoll 9y agoYes, Threadripper presents two NUMA nodes.
- yarg 9y agoSo this one I actually know - Threadripper can be configured (to present) in NUMA or UMA modes.
- sliken 9y agoSounds 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?
- yarg 9y agoYes, 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.
- microcolonel 9y agoI guess the next step is to make game engines and web browsers NUMA aware.
- JimmyAustin 9y agoI'd put money that automatically handling the affinity per CCX would give you a good chunk of performance boost, but that it would require a substantial amount of work to the OS that wouldn't be completed before benchmarks and reviews came out. Given that Ryzen 3/5/7 performance has improved since they were released, but only a few of the reviews have been updated, it's likely that AMD wanted to avoid that and put in Game Mode as a stopgap.
- sitkack 9y agoIf it is in their power to do so, they should do it. It helps users. If it happens in the OS or it happens in hardware, it really doesn't matter.
- dantiberian 9y agoFrom the last page: http://www.anandtech.com/show/11726/retesting-amd-ryzen-threadrippers-game-mode-halving-cores-for-more-performance/17 http://www.anandtech.com/show/11726/retesting-amd-ryzen-thre... (I think this answers your question?) > Robert Hallock on AMD's Threadripper webcast has stated that Windows Scheduler is not capable of specifically zeroing out a full die to have the same effect. The UMA/NUMA implementation can be managed with Windows Scheduler to assign threads to where the data is (or assign data to where the threads are), but as far as fully disabling a die in the OS requires a restart.
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- 0xbear 9y agoI 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.