Date: Tue, 16 Nov 2004 12:11:21 +1030 From: "Wilkinson, Alex" <alex.wilkinson@dsto.defence.gov.au> To: freebsd-current@freebsd.org Subject: Re: Re: Detection of HTT Message-ID: <20041116014121.GJ56252@squash.dsto.defence.gov.au> In-Reply-To: <20041115043907.GI51636@squash.dsto.defence.gov.au> References: <20041115043907.GI51636@squash.dsto.defence.gov.au>
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Is it possible to find out whether HTT is turned on in the BIOS without having to reboot ? acpidump(8) ? It's just that I notice that I have a HTT capable CPU: CPU: Intel(R) Pentium(R) 4 CPU 2.80GHz (2793.19-MHz 686-class CPU) Origin = "GenuineIntel" Id = 0xf29 Stepping = 9 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> And options SMP compiled into the kernel, but lack any message in /var/run/dmesg about HTT being enabled. - aW Wilkinson, Alex wrote: >Why is HTT turned off out of the box ? I thought HTT was meant to be a >hardware 'performance enhancing' feature. > >Why do we disable it ? > > - aW FreeBSD will use HTT if the system has it enabled (usually controlled in the BIOS) and the kernel is compiled for SMP. There are ways to manually disable HTT but leave SMP enabled in the OS, but the default is to use it if the above two requirements are met. However, the OS scheduler is not HTT-aware, so HTT will give a somewhat mixed performance. Scott
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