Date: Tue, 20 Apr 2004 10:38:37 +0300 From: Rumen Telbizov <altares@e-card.bg> To: Kris Kennaway <kris@obsecurity.org> Cc: stable@freebsd.org Subject: Re: HTT and SMP question Message-ID: <20040420073837.GS32493@e-card.bg> In-Reply-To: <20040419093523.GA34419@xor.obsecurity.org> References: <20040419085841.GB64662@freenix.no> <20040419090049.GA51659@chihiro.leafy.idv.tw> <20040419092052.GD64662@freenix.no> <20040419093523.GA34419@xor.obsecurity.org>
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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! Thank you in advance! Rumen Telbizov
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