Date: Tue, 18 Mar 2003 17:14:10 -0800 From: Brooks Davis <brooks@one-eyed-alien.net> To: Gregory Bond <gnb@itga.com.au> Cc: stable@FreeBSD.ORG Subject: Re: Hyperthreading in 4.8RC Message-ID: <20030318171410.A21657@Odin.AC.HMC.Edu> In-Reply-To: <200303190102.MAA10267@lightning.itga.com.au>; from gnb@itga.com.au on Wed, Mar 19, 2003 at 12:02:43PM %2B1100 References: <200303190102.MAA10267@lightning.itga.com.au>
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--HlL+5n6rz5pIUxbD Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Wed, Mar 19, 2003 at 12:02:43PM +1100, Gregory Bond wrote: >=20 > I have an HP Vl420 (P4-1.6, i845 Mb). AFAIK, this MB is not an explicitl= y MP=20 > motherboard - it has only 1 CPU slot. The latest 4.8 kernel seems to sho= w me > that this CPU has Hyperthreading: >=20 > CPU: Intel(R) Pentium(R) 4 CPU 1.60GHz (1594.10-MHz 686-class CPU) > Origin =3D "GenuineIntel" Id =3D 0xf12 Stepping =3D 2 > Features=3D0x3febfbff<FPU,VME,DE,PSE,TSC,MSR,PAE,MCE,CX8,APIC,SEP,MTRR,= PGE,MCA,C > MOV,PAT,PSE36,CLFLUSH,DTS,ACPI,MMX,FXSR,SSE,SSE2,SS,HTT,TM> >=20 > (Feature HTT =3D=3D hyperthreading, according to identcpu.c). >=20 > So I added the SMP options (IOAPIC, SMP, HTT) to the kernal config and > rebooted. It seems to be running OK, and I see lots of IOAPIC and SMP-li= ke > things in the dmesg, e.g.: >=20 > FreeBSD/SMP: Multiprocessor motherboard > cpu0 (BSP): apic id: 0, version: 0x00050014, at 0xfee00000 > io0 (APIC): apic id: 2, version: 0x00178020, at 0xfec00000 >=20 > but I don't see the=20 > Hyperthreading: 2 logical CPUs > message that I would expect, nor any reference to cpu1. >=20 > What does this imply? =20 >=20 > Do I need an "official" SMP motherboard to take advantage of Hyperthreadi= ng? Or > do I need a XEON processor, not just a plain P4 (and if so, is the HTT Fe= ature > is lying to me?) Or is there some other magic I can perform to get it wo= rking > on the current hardware? That CPU doesn't really support hyperthreading except in the vacuous sense. It's got enough support that you can boot an SMP kernel, but plain P4's below 3.06GHz don't actually have additional logical CPUs available. -- Brooks --=20 Any statement of the form "X is the one, true Y" is FALSE. PGP fingerprint 655D 519C 26A7 82E7 2529 9BF0 5D8E 8BE9 F238 1AD4 --HlL+5n6rz5pIUxbD Content-Type: application/pgp-signature Content-Disposition: inline -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.2.1 (GNU/Linux) iD8DBQE+d8RhXY6L6fI4GtQRAoyiAJ9riPn469hAPMV2xn3zMtM0eaoodQCgy3n3 e9SVyTsuRSv59cN/S00UnGE= =cDKI -----END PGP SIGNATURE----- --HlL+5n6rz5pIUxbD-- To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-stable" in the body of the message
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