[CentOS] Kernel ELsmp vs EL

Jim Perrin jperrin at gmail.com
Fri Sep 8 01:43:14 UTC 2006

> Awesome... Next server has HT.. So I'll give that a try!

Keep in mind that HT is its own special brand of hell, and isn't
really *true* SMP. The kernel will work fine, and you'll see 2x the
processors, but at most you'll get about a 3% performance boost, and
at worst, it'll actually hurt performance. Some motherboards have
buggy HT implementations and may cause some locking or slowness.
Sometimes this can be resolved by appending apci=ht to your kernel
boot line. With HT you also have the possibility of cache thrashing,
which can/will impact performance. Make sure you know what you're
getting into.

During times of universal deceit, telling the truth becomes a revolutionary act.
George Orwell

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