The scheduler and hyperthreading [LWN.net]Hyperthreading is a hardware technique where a single CPU behaves as if it were multiple (usually two) virtual processors. When one virtual processor stalls (on a cache miss, for example), the other runs. Hyperthreading can yield significant performance improvements (numbers of around 30% have been floated) for a very small silicon investment. And the software side is free: a hyperthreaded process
Block layer discard requests [LWN.net]
