Date: Thu, 16 Dec 2004 15:17:02 -0500 From: John Baldwin <jhb@FreeBSD.org> To: freebsd-smp@FreeBSD.org Cc: Andriy Tkachuk <ant@emict.com> Subject: Re: doc's inaccuracy? about machdep.hlt_logical_cpus Message-ID: <200412161517.02158.jhb@FreeBSD.org> In-Reply-To: <200412161311.10526.ant@emict.com> References: <200412161311.10526.ant@emict.com>
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On Thursday 16 December 2004 06:11 am, Andriy Tkachuk wrote: > Hi folks. > > ant# uname -r > 5.3-STABLE > > man smp > ... > FreeBSD supports hyperthreading on Intel CPU's on the i386 platform. > Since using logical CPUs can cause performance penalties under certain > loads, the logical CPUs can be disabled by setting the > machdep.hlt_logical_cpus sysctl to one. > ^^^^^^^^^^^^^^^^^^^^^^^^ > > ant# sysctl -a | grep machdep.hlt > machdep.hlt_cpus: 0 > > is this the one that is mentioned in smp(4) ? No. The sysctl only shows up if you have a CPU that has more than one logical core, so if your CPU doesn't have logical cores, the sysctl won't exist. -- John Baldwin <jhb@FreeBSD.org> <>< http://www.FreeBSD.org/~jhb/ "Power Users Use the Power to Serve" = http://www.FreeBSD.org
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