On Wed, Feb 27, 2002 at 04:26:35PM -0800, Frost, Stephen C wrote: > > All - > > I have RTFM'd, with little luck. Can some enlightened soul impart knowledge > upon me, thus letting me know why any kernels compiled with SMP enabled seem > to be slowing the whole system down? Throughput goes down by 40%. Tasks > take twice as long to run, etc, etc... > > I have multiple boxes (Dells, IBM's, Microns, Gateways...) running FreeBSd > 4.5, all showing the same phenomenon. I initially mistook it for a NIC > driver issue, but it appears to be system-wide. And is directly linked to > SMP: two kernels, identical EXCEPT that one has SMP enabled, the other not. > The enabled kernel that *should* be fully utilizing multi-procs is suddenly > effectively running at half speed. > > Is this a config issue? Any helpful hints? Or is it better just to keep > SMP disabled on a multi-proc box? >
Is this an old Pentium? If so, update to a recent -stable; a fix was committed a few weeks ago fixing a problem where the caches on both processors were not enabled on Pentiums. Otherwise, we have a few PII and PIII boxes here that work quite under 4.5. (oh, you might want to try the freebsd-smp list) -- Chris D. Faulhaber - [EMAIL PROTECTED] - [EMAIL PROTECTED] -------------------------------------------------------- FreeBSD: The Power To Serve - http://www.FreeBSD.org
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