Date: Fri, 27 May 2005 10:47:57 -0700 From: Kris Kennaway <kris@obsecurity.org> To: Jacob S <stormspotter@6Texans.net> Cc: freebsd-questions@freebsd.org, Dmitry Mityugov <dmitry.mityugov@gmail.com> Subject: Re: Problem with HT support in 5.4 Message-ID: <20050527174757.GE79637@xor.obsecurity.org> In-Reply-To: <20050527093046.748e33c1@jacob.6texans.net> References: <20050527085445.38de5553@jacob.6texans.net> <b7052e1e05052707056d4faa4@mail.gmail.com> <20050527093046.748e33c1@jacob.6texans.net>
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--GxcwvYAGnODwn7V8 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Fri, May 27, 2005 at 09:30:46AM -0500, Jacob S wrote: > On Fri, 27 May 2005 18:05:48 +0400 > Dmitry Mityugov <dmitry.mityugov@gmail.com> wrote: >=20 > > On 5/27/05, Jacob S wrote: > > > Hello list, > > >=20 > > > I upgraded a few 5.3 servers to 5.4 yesterday and everything seemed > > > to go well. After booting the new kernel, dmesg correctly showed 2 > > > logical cpus (1 xeon with HT). > > >=20 > > > However, when I look at top's output, it always shows at least 50% > > > cpu idle time - even when the load is above 10. To confirm this, I > > > ran burnP6 from the cpuburn port - even with over a hundred apache > > > processes going, exim running and a few other things, top still > > > reported the cpu as 50% idle. The 'C' column in top, between 'State' > > > and 'Time' also shows everything as being run on cpu 0. > > >=20 > > > `ps ax | grep cpu` reports this: > > > 11 ?? RL 0:00.00 [idle: cpu1] > > > 12 ?? RL 931:45.24 [idle: cpu0] > > > 108 ?? DL 0:04.02 [schedcpu] > > >=20 > > > So it looks like smp support is enabled and it sees the HT enabled > > > processor, but it's not using the second logical cpu. Is there > > > something I missed in compiling the kernel, or is this a bug? I have > > > confirmed it on two 5.4 servers now. > >=20 > > Oh, wait, it is probably just the last HT security patch, > > ftp://ftp.freebsd.org/pub/FreeBSD/CERT/advisories/FreeBSD-SA-05:09.htt.= asc. >=20 > hmm... So basically, SMP can be enabled, but it won't use HT even if it > sees a capable processor?=20 By default..it's a trivial matter of setting a loader tunable. Please read the advisory. Kris --GxcwvYAGnODwn7V8 Content-Type: application/pgp-signature Content-Disposition: inline -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.1 (FreeBSD) iD8DBQFCl11MWry0BWjoQKURAu4mAJ4rTSVfE1A81rwXlDGluNNpCmhZFACg6Nfs XDiMnuCeiDzdM9N+sTzkg3E= =QAgb -----END PGP SIGNATURE----- --GxcwvYAGnODwn7V8--
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