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From TFA: >> We're planning to get some high core count machines to be new compute machines in our environment of general multi-user Unix login servers I thin
by phkahler 5y ago
From TFA:
>> We're planning to get some high core count machines to be new compute machines in our environment of general multi-user Unix login servers
I think the "general multi-user Ubix login" thing assumes different users on the same CPU. Unless they're actually going to have more CPUs than users. It seems like sharing a CPU is actually less secure than sharing one via SMT because of all those SMT-specific exploits (in addition to whatever exploits might be possible due to CPU sharing).
- toast0 5y agoSharing an SMT is IMHO less secure, because the adversary can probe while the victim is running. Sharing a CPU means you can only probe the effects. It would make sense to me for a traditional multiuser shell server to have a scheduling policy prohibiting SMT sharing between users. As long as the scheduler work is not expensive, it would seem almost no-cost vs disabling SMT in case all users only run a single thread, but you can still get whatever benefits SMT provides within a user's workload.