Re: Hyper-Threading Vulnerability

From: Arjan van de Ven
Date: Sat May 14 2005 - 03:33:34 EST


On Fri, 2005-05-13 at 22:51 +0000, linux@xxxxxxxxxxx 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.


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