Date: Wed, 12 Jan 2005 13:15:42 +0200 From: Giorgos Keramidas <keramida@ceid.upatras.gr> To: freebsd-questions@FreeBSD.org Subject: Re: Hyperthreading hurts 5.3? Message-ID: <20050112111542.GA1651@orion.daedalusnetworks.priv> In-Reply-To: <167683180.20050112072014@wanadoo.fr> References: <9094-SnapperMsgD246FC56BE0A255B@68.243.126.247> <20050112014359.GA3722@gothmog.gr> <B8CC38DE-6455-11D9-87A5-000D93AD26C8@tntluoma.com> <35de0c30050111210235ea3060@mail.gmail.com> <20050112052901.GA61033@osiris.chen.org.nz> <167683180.20050112072014@wanadoo.fr>
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On 2005-01-12 07:20, Anthony Atkielski <atkielski.anthony@wanadoo.fr> wrote: > Jonathan Chen writes: > JC> Not true on 5.3+ GENERIC systems. If you look at dmesg, you'll see the > JC> second virtual CPU launched as well as the extra column in top(1) if > JC> you enable HTT in the BIOS. > > Well, now I'm confusing. I have an Asus P4P800-E Deluxe MB with an > Intel P4 processor mounted on it, and dmesg looks like this: > > FreeBSD 5.3-RELEASE #1: Mon Dec 27 05:52:34 CET 2004 > root@freebie.atkielski.com:/usr/obj/usr/src/sys/FREEBIE > ACPI APIC Table: <A M I OEMAPIC > > Timecounter "i8254" frequency 1193182 Hz quality 0 > CPU: Intel(R) Pentium(R) 4 CPU 3.00GHz (2998.57-MHz 686-class CPU) > Origin = "GenuineIntel" Id = 0xf34 Stepping = 4 > Features=0xbfebfbff<FPU,VME,DE,PSE,TSC,MSR,PAE,MCE,CX8,APIC,SEP,MTRR,PGE,MCA,CMOV,PAT,PSE36,CLFLUSH,DTS,ACPI,MMX,FXSR,SSE,SSE2,SS,HTT,TM,PBE> > Hyperthreading: 2 logical CPUs > real memory = 1073414144 (1023 MB) > avail memory = 1045057536 (996 MB) > ioapic0: Changing APIC ID to 2 > ioapic0 <Version 2.0> irqs 0-23 on motherboard > npx0: [FAST] > npx0: <math processor> on motherboard > npx0: INT 16 interface > acpi0: <A M I OEMRSDT> on motherboard > acpi0: Power Button (fixed) > Timecounter "ACPI-fast" frequency 3579545 Hz quality 1000 > acpi_timer0: <24-bit timer at 3.579545MHz> port 0x808-0x80b on acpi0 > cpu0: <ACPI CPU> on acpi0 > pcib0: <ACPI Host-PCI bridge> port 0xcf8-0xcff on acpi0 > pci0: <ACPI PCI bus> on pcib0 > agp0: <Intel 82865 host to AGP bridge> mem 0xf8000000-0xfbffffff at device 0.0 on pci0 > pcib1: <ACPI PCI-PCI bridge> at device 1.0 on pci0 > pcib1: could not get PCI interrupt routing table for \\_SB_.PCI0.P0P1 - AE_NOT_FOUND > pci1: <ACPI PCI bus> on pcib1 > pci1: <display, VGA> at device 0.0 (no driver attached) > [...] > > Do I have two processors or not? The BIOS says that hyperthreading is > enabled (and it wouldn't say anything at all if the processor were not > HT-capable, according to the manual). > > Where's the second logical processor? I recompiled my own kernel but I > didn't modify any of the CPU stuff (I don't think). You need to enable SMP too, to allow the FreeBSD kernel to use the second (hyper-threaded) CPU. My workstation is a P4 @ 2800, which does support HTT, but I haven't enabled SMP in my kernel configuration, so it is not used: % # grep 'options[[:space:]]*SMP' /usr/src/sys/conf/NOTES % options SMP # Symmetric MultiProcessor Kernel % # grep 'options[[:space:]]*SMP' \ % /usr/src/sys/`uname -m`/conf/`uname -v | sed -e 's:.*/::' ` % # dmesg % Copyright (c) 1992-2005 The FreeBSD Project. % Copyright (c) 1979, 1980, 1983, 1986, 1988, 1989, 1991, 1992, 1993, 1994 % The Regents of the University of California. All rights reserved. % FreeBSD 6.0-CURRENT #0: Tue Jan 11 17:03:06 EET 2005 % root@orion.daedalusnetworks.priv:/usr/obj/usr/src/sys/ORION % WARNING: WITNESS option enabled, expect reduced performance. % Timecounter "i8254" frequency 1193182 Hz quality 0 % CPU: Intel(R) Pentium(R) 4 CPU 2.80GHz (2806.37-MHz 686-class CPU) % Origin = "GenuineIntel" Id = 0xf33 Stepping = 3 % Features=0xbfebfbff<FPU,VME,DE,PSE,TSC,MSR,PAE,MCE,CX8,APIC,SEP,MTRR,PGE,\ %MCA,CMOV,PAT,PSE36,CLFLUSH,DTS,ACPI,MMX,FXSR,SSE,SSE2,SS,HTT,TM,PBE> % Hyperthreading: 2 logical CPUs % real memory = 468647936 (446 MB) % avail memory = 449392640 (428 MB) % npx0: [FAST] % npx0: <math processor> on motherboard % npx0: INT 16 interface % acpi0: <RS300 AWRDACPI> on motherboard % acpi0: Power Button (fixed) % Timecounter "ACPI-fast" frequency 3579545 Hz quality 1000 % acpi_timer0: <32-bit timer at 3.579545MHz> port 0x4008-0x400b on acpi0 % cpu0: <ACPI CPU> on acpi0 % acpi_button0: <Power Button> on acpi0
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