Re: HTT on current

Since HTT can lead to performance degradation in some (many?) cases,
the second logical CPU's are halted by default.  They are enabled,
however, in order for interrupt routing to work right.  Work is ongoing
to make an HTT-aware scheduler, and make the enabling of the logical
cores optional.

Scott

Mike Jakubik wrote:
> Its seems to be working for me ok with the sysctl machdep.hlt_logical_cpus
> variable set to 0. (I wonder why its not by default)
> 
> # sysctl machdep.hlt_logical_cpus=0
> machdep.hlt_logical_cpus: 2 -> 0
> # uname -a
> FreeBSD newns.trigger.net 5.1-CURRENT FreeBSD 5.1-CURRENT #0: Fri Aug 22
> 19:07:26 EDT 2003     root_at_newns.trigger.net:/usr/src/sys/i386/compile/NS1
> i386
> 
> I am running on an Intel s875wp1 server MB.
> 
> 
>>-----Original Message-----
>>From: Marc G. Fournier [mailto:scrappy_at_hub.org]
>>Sent: Sunday, August 24, 2003 12:49 PM
>>To: Kris Kennaway
>>Cc: Yamada Ken Takeshi; mikej_at_trigger.net; current_at_freebsd.org
>>Subject: Re: HTT on current
>>
>>
>>
>>yes:
>>
>>ganymede# grep SMP /usr/src/sys/i386/conf/kernel
>>options         SMP                     # Symmetric MultiProcessor Kernel
>>
>>and:
>>
>>CPU: Intel(R) Pentium(R) 4 CPU 2.40GHz (2393.19-MHz 686-class CPU)
>>  Origin = "GenuineIntel"  Id = 0xf27  Stepping = 7
>>
>>Features=0xbfebfbff<FPU,VME,DE,PSE,TSC,MSR,PAE,MCE,CX8,APIC,SEP,MT
> 
> RR,PGE,MCA,CMOV,PAT,PSE36,CLFLUSH,DTS,ACPI,MMX,FXSR,SSE,SSE2,SS,HTT,TM,PBE>
> 
>>real memory  = 536805376 (511 MB)
>>avail memory = 515919872 (492 MB)
>>Programming 24 pins in IOAPIC #0
>>IOAPIC #0 intpin 2 -> irq 0
>>FreeBSD/SMP: Multiprocessor System Detected: 1 CPUs
>> cpu0 (BSP): apic id:  0, version: 0x00050014, at 0xfee00000
>> io0 (APIC): apic id:  2, version: 0x00178020, at 0xfec00000
>>
>>shouldn't it be starting up a second CPU, for the HTT?
>>
>>
>>On Sun, 24 Aug 2003, Kris Kennaway wrote:
>>
>>
>>>On Sun, Aug 24, 2003 at 01:06:28PM -0300, Marc G. Fournier wrote:
>>>
>>>>
>>>>ganymede# sysctl machdep.hlt_logical_cpus
>>>>sysctl: unknown oid 'machdep.hlt_logical_cpus'
>>>>ganymede# uname -a
>>>>FreeBSD ganymede.hub.org 5.1-CURRENT FreeBSD 5.1-CURRENT #1:
>>
>>Sat Aug 23 00:08:54 ADT 2003
>>root_at_ganymede.hub.org:/usr/obj/usr/src/sys/kernel  i386
>>
>>>Is this a SMP kernel?
>>>
>>>ports-i386%uname -a
>>>FreeBSD dosirak.kr.freebsd.org 5.1-CURRENT FreeBSD 5.1-CURRENT
>>
>>#8: Sat Aug  9 15:43:12 KST 2003
>>root_at_dosirak.kr.freebsd.org:/usr/src/sys/i386/compile/DOSIRAK  i386
>>
>>>ports-i386%sysctl machdep.hlt_logical_cpus
>>>machdep.hlt_logical_cpus: 1
>>>
>>>Kris
>>>
>>
> 
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