[xakahnx]

This is still a disaster with hyperthreading where you can have two threads contending for a lock on the same physical core.

Even if your thread won't be scheduled off the core I don't know if you might still have irqs stealing time during the critical section.

[touisteur]

Can't you isolate cores from irqs with irq affinities? I'd be more worried by SMM stealing CPU time (ugh... talk about sad stories of 'real-time' Linux...).