Re: Hyper-Threading Vulnerability

Arjan van de Ven
2005-05-14T08:32:40Z

On Fri, 2005-05-13 at 22:51 +0000, linux@horizon.com wrote:
> If RDTSC is too annoying to disable, just interpret the same flag as a
> "schedule me solo" flag that prevents scheduling anything else (at least,
> not sharing the same ->mm) on the other virtual processor. (Of course,
> the time should count double for scheduler fairness purposes.)

rdtsc is so unreliable on current hardware that no userspace app should
be using it anyway; it's not synchronized on SMP, powermanagement
impacts the rate of the ticks all the time etc etc.
Basically it's worthless on modern machines for anything but in-kernel
busy loops.