Date: Tue, 10 Mar 2015 01:24:35 +0000 From: "Pokala, Ravi" <rpokala@panasas.com> To: Rui Paulo <rpaulo@me.com> Cc: "freebsd-hackers@freebsd.org" <freebsd-hackers@freebsd.org> Subject: Re: detecting hyperthreading Message-ID: <D123957A.12F6CA%rpokala@panasas.com> In-Reply-To: <9F2E1411-B517-4BC8-AF61-BB15EE35083C@me.com> References: <D12358C5.12F652%rpokala@panasas.com> <9F2E1411-B517-4BC8-AF61-BB15EE35083C@me.com>
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-----Original Message----- From: Rui Paulo <rpaulo@me.com> Date: 2015-03-09, Monday at 18:19 To: Ravi Pokala <rpokala@panasas.com> Cc: "freebsd-hackers@freebsd.org" <freebsd-hackers@freebsd.org> Subject: Re: detecting hyperthreading >I think that sysctl didn't fully control hyperthreading: you can disable >it on the BIOS and FreeBSD never exported that information. If you used >that tunable, it would simply disable the Pentium 4 Hyperthreading. I never tried to *change* it at runtime; I just used it's *existence* as an indicator that HT was enabled. (Aside - why did it not exist at all when HT was disabled, as opposed to always existing and just having zero/non-zero values?) -Ravi >-- >Rui Paulo
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