Hyperthreading with SMP in 5.2

Andrew Edwards (Olympic Shaver Centre) andrew at shavers.co.uk
Wed Jan 14 03:15:40 PST 2004


Could anyone clarify the level of support for Pentium 4 hyperthreading in 5.2? I understand that the kernel is now smp aware by default but does it handle the logical cpu's of hyperthreading in the same manner as it would a physical cpu?

I ask as for the best part my machine rarely goes above 50% cpu utilisation. However using -j2 when building the kernel or world for example will give me nearer full use, which I can appreciate as it generates concurrent processes that likely get divided over the two logical cpu.

Not being fully aware of the technical bits to hyperthreading is the above scenario as good as it can be and is making good use of the cpu, i.e if I run a single cpu heavy process, whereas without hyperthreading I would see 100% usage now I only see around 50%.


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