Date: Mon, 10 Mar 2003 13:00:13 -0500 (EST) From: John Baldwin <jhb@FreeBSD.org> To: Richard Nyberg <rnyberg@it.su.se> Cc: freebsd-smp@freebsd.org Subject: RE: hyperthreading randomness Message-ID: <XFMail.20030310130013.jhb@FreeBSD.org> In-Reply-To: <20030308121852.GA25380@murmeldjur.it.su.se>
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On 08-Mar-2003 Richard Nyberg wrote: > I have a Dell Precision 450 with 2 xeon CPU:s. > The weird thing is that it randomly boots up > with either 2 or 4 CPUs on the same 4-STABLE kernel. > 2 more often than 4. It seems a bit unpredictable :( Hmm, I have no idea about that one. Hmm, it seems to be a "feature" of the BIOS perhaps. It seems that it may be listing the second CPU with an APIC ID of 3 (it's second core) instead of 2 (it's first core) in which case the HTT code sees that something is not right and doesn't start up any extra processors. > CPU: Intel(R) Xeon(TM) CPU 2.66GHz (2657.82-MHz 686-class CPU) > Origin = "GenuineIntel" Id = 0xf27 Stepping = 7 > > Features=0xbfebfbff<FPU,VME,DE,PSE,TSC,MSR,PAE,MCE,CX8,APIC,SEP,MTRR,PGE,MCA,CMOV,PAT,PSE36,CLFLUS > H,DTS,ACPI,MMX,FXSR,SSE,SSE2,SS,HTT,TM,PBE> > Hyperthreading: 2 logical CPUs > > Diff of dmesg with 2 and 4 CPUs. > > --- /tmp/dmesg.old Sat Mar 8 12:10:33 2003 > +++ /var/run/dmesg.boot Sat Mar 8 11:57:38 2003 > @@ -19,7 +19,9 @@ > Programming 24 pins in IOAPIC #2 > FreeBSD/SMP: Multiprocessor motherboard > cpu0 (BSP): apic id: 0, version: 0x00050014, at 0xfee00000 > - cpu1 (AP): apic id: 3, version: 0x00050014, at 0xfee00000 > + cpu1 (AP): apic id: 1, version: 0x00050014, at 0xfee00000 > + cpu2 (AP): apic id: 2, version: 0x00050014, at 0xfee00000 > + cpu3 (AP): apic id: 3, version: 0x00050014, at 0xfee00000 > io0 (APIC): apic id: 4, version: 0x00178020, at 0xfec00000 > io1 (APIC): apic id: 5, version: 0x00178020, at 0xfec80000 > io2 (APIC): apic id: 6, version: 0x00178020, at 0xfec80800 > @@ -103,6 +105,8 @@ > APIC_IO: Testing 8254 interrupt delivery > APIC_IO: routing 8254 via IOAPIC #0 intpin 2 > SMP: AP CPU #1 Launched! > +SMP: AP CPU #3 Launched! > +SMP: AP CPU #2 Launched! > ad0: 38146MB <WDC WD400BB-75DEA0> [77504/16/63] at ata0-master UDMA100 > acd0: DVD-ROM <LITEON DVD-ROM LTD163> at ata1-master UDMA33 > acd1: CD-RW <HL-DT-ST GCE-8481B> at ata1-slave UDMA33 > > -Richard > > To Unsubscribe: send mail to majordomo@FreeBSD.org > with "unsubscribe freebsd-smp" in the body of the message -- John Baldwin <jhb@FreeBSD.org> <>< http://www.FreeBSD.org/~jhb/ "Power Users Use the Power to Serve!" - http://www.FreeBSD.org/ To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-smp" in the body of the message
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