Date: Tue, 20 Apr 2004 01:13:34 -0700 From: Kris Kennaway <kris@obsecurity.org> To: Rumen Telbizov <altares@e-card.bg> Cc: Kris Kennaway <kris@obsecurity.org> Subject: Re: HTT and SMP question Message-ID: <20040420081334.GA56291@xor.obsecurity.org> In-Reply-To: <20040420073837.GS32493@e-card.bg> References: <20040419085841.GB64662@freenix.no> <20040419090049.GA51659@chihiro.leafy.idv.tw> <20040419092052.GD64662@freenix.no> <20040419093523.GA34419@xor.obsecurity.org> <20040420073837.GS32493@e-card.bg>
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[-- Attachment #1 --] On Tue, Apr 20, 2004 at 10:38:37AM +0300, Rumen Telbizov wrote: > Hello, > > On Mon, Apr 19, 2004 at 02:35:23AM -0700, Kris Kennaway wrote: > > On Mon, Apr 19, 2004 at 11:20:52AM +0200, Morten A. Middelthon wrote: > > > sysctl -w machdep.hlt_logical_cpus=0 > > > > > > that did the trick. I added it to loader.conf as well. > > > > > > regards, > > > > Note that HTT causes worse performance in many workloads, which is why > > that sysctl defaults to off. > > Would you please point out some cases when HTT with machdep.hlt_logical_cpus=0 > causes worse performance than machdep.hlt_logical_cpus=1? > I am using an HTT Xeon since recently and in my tests it showed that > machdep.hlt_logical_cpus=0 is better! > A simple ubench (spawning 2 processes) gives better results in 0 mode! My parallel package builds are slower on build machines with HTT. It's not a magic bullet. Kris [-- Attachment #2 --] -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.2.4 (FreeBSD) iD8DBQFAhNuuWry0BWjoQKURAvUoAKDzuswtck4lQP7ut1lMBAd1eKhwSQCg9+hd 1Sg/8LEbl87aCgIhPZJenP4= =NsB8 -----END PGP SIGNATURE-----
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