SMP on SMP-capable system with one processor

Lowell Gilbert freebsd-questions-local at
Thu Sep 16 17:01:56 PDT 2004

"adp" <dap99 at> writes:

> We have several Dell-based systems that are dual-processor capable, but have
> only one processor. The FreeBSD 4.9 kernels for each system is compiled with
> SMP support, even though there is only one processor on each system right
> now.
> Would this actually reduce performance on a single processor system? I know
> that SMP kernels have to worry about special locking, and may be doing
> unnecessary work.

Sure.  If you don't have a multiprocessor system, you may see a very
small performance improvement by removing the SMP support.  You'd need
to make careful measurements to notice the difference, though.

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