On 10/2/2010 6:08 PM, Nathen wrote:
Pretty simple question really, does Debian i.e. the current Linux Kernel handle hyperthreading well? I have a server running on an Intel Atom D510, should I have HT enabled or disabled to get the best performance? Thanks. :)
Recently (kernel 2.6.31 or so) there has been a separate kernel configuration option to optimize for SMT (Intel's word for it is "hyperthreading"). Separate from SMP (multiple processor). Under SMT, a single core running two threads looks like two cores to most of the kernel itself and to user programs. This has been true for a long time. Only now, there is more support and optimization for it. If your kernel has it enabled, some workloads won't see any difference, but some will benefit a lot. I think it is enabled by default in the most recent stock kernels (please correct me if I'm wrong.)
Note, you may need to enable hyperthreading in your BIOS, as well.I would enable it for Core i7 and Atom. P4-era machines could sometimes have software compatibility issues with it enabled, but I think Debian and Atoms are good.