Date: Wed, 27 Feb 2002 20:56:51 -0500 From: Chris Faulhaber <jedgar@fxp.org> To: "Frost, Stephen C" <stephen.c.frost@intel.com> Cc: "'freebsd-questions@freebsd.org'" <freebsd-questions@freebsd.org>, "'freebsd-hackers@freebsd.org'" <freebsd-hackers@freebsd.org> Subject: Re: FreeBSD, SMP and Performance Speeds? Message-ID: <20020228015651.GA90541@peitho.fxp.org> In-Reply-To: <B9ECACBD6885D5119ADC00508B68C1EA0288A6E1@orsmsx107.jf.intel.com> References: <B9ECACBD6885D5119ADC00508B68C1EA0288A6E1@orsmsx107.jf.intel.com>
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--AhhlLboLdkugWU4S Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Wed, Feb 27, 2002 at 04:26:35PM -0800, Frost, Stephen C wrote: >=20 > All - >=20 > I have RTFM'd, with little luck. Can some enlightened soul impart knowle= dge > upon me, thus letting me know why any kernels compiled with SMP enabled s= eem > to be slowing the whole system down? Throughput goes down by 40%. Tasks > take twice as long to run, etc, etc... >=20 > 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 no= t. > The enabled kernel that *should* be fully utilizing multi-procs is sudden= ly > effectively running at half speed. >=20 > Is this a config issue? Any helpful hints? Or is it better just to keep > SMP disabled on a multi-proc box? >=20 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) --=20 Chris D. Faulhaber - jedgar@fxp.org - jedgar@FreeBSD.org -------------------------------------------------------- FreeBSD: The Power To Serve - http://www.FreeBSD.org --AhhlLboLdkugWU4S Content-Type: application/pgp-signature Content-Disposition: inline -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.0.6 (FreeBSD) Comment: FreeBSD: The Power To Serve iEYEARECAAYFAjx9jmMACgkQObaG4P6BelBnuwCffzjYbdp6FfLmNLh6QNVhusDm 8TkAoIEBY2wUrKbp6/diZPD0FHjVmXCW =xlGF -----END PGP SIGNATURE----- --AhhlLboLdkugWU4S-- To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-hackers" in the body of the message
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