Date: Thu, 13 Feb 2003 11:26:33 -0800 From: Darren Pilgrim <dmp@pantherdragon.org> To: =?ISO-8859-1?Q?=22Roub=EDcek_Zdenek_=28PragoNet=29=22?= <Zdenek.Roubicek@pragonet.cz> Cc: stable@FreeBSD.ORG Subject: Re: 4.7-stable & smp Message-ID: <3E4BF169.7010402@pantherdragon.org> In-Reply-To: <9256D57F598E6C41B288AA7DB94F29C9604A2A@pgnmail1.pgnaplikace.cz> References: <9256D57F598E6C41B288AA7DB94F29C9604A2A@pgnmail1.pgnaplikace.cz>
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Roubícek Zdenek (PragoNet) wrote: > > Any chance to disable it (hyperthreading)? I just want 2 physical CPUs not 4 virtual working. JOOC, why don't you want it enabled? My understanding of the concept is HT allows the CPU to more fully utilize the available host bus bandwidth since a single, deep pipline won't normally make full use of a 200MHz host bus. Assuming the SMP code in FreeBSD is effective, I'd think you seriously cut into the CPU's performance by disabling HT. >From: Erik Trulsson [mailto:ertr1013@student.uu.se] >> >>On Wed, Feb 12, 2003 at 03:43:53PM -0800, Mike Hoskins wrote: >> >>>I don't recall seeing mention of "CPU #3" before. (It is a 2 CPU box.) >>>Is this actually something broken (seems to work just fine), or just >>>semantics? :) It does say "2 logical CPUs": >> >>It is not a bug, it is a feature. :-) >>The magical word here is "Hyperthreading". With Intel's latest P4 and >>Xeon CPUs you can treat each physical CPU as two logical CPUs. >>Basic support for this was recently added to -stable. You are seeing >>the results of this. To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-stable" in the body of the message
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