Core i7 anyone else?

Ivan Voras ivoras at freebsd.org
Wed Nov 19 04:00:08 PST 2008


Takanori Watanabe wrote:
> Hi, I recently bought Core i7 machine(for 145,000JPY: about $1500)
> and sometimes hangs up oddly.
> When in the state, some specific process only works and 
> replys ping, but not reply any useful information.
> 
> I suspect it may caused by CPU power management, so I cut 
> almost all CPU power management feature on BIOS parameter.
> 
> Are there any people encouterd such trouble?
> And on this machine build world in SCHED_ULE(15min.) is slower 
> than SCHED_4BSD(12min.).


I don't know but this:

> ===dmesg===
> http://www.init-main.com/corei7.dmesg
> or
> http://pastebin.com/m187f77aa
> (if host is down)

CPU: Intel(R) Core(TM) i7 CPU         920  @ 2.67GHz (2684.00-MHz
686-class CPU)
  Origin = "GenuineIntel"  Id = 0x106a4  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>

Features2=0x98e3bd<SSE3,DTES64,MON,DS_CPL,VMX,EST,TM2,SSSE3,CX16,xTPR,PDCM,SSE4.1,SSE4.2,POPCNT>
  AMD Features=0x28100000<NX,RDTSCP,LM>
  AMD Features2=0x1<LAHF>
  Cores per package: 8
  Logical CPUs per core: 2
real memory  = 3211264000 (3062 MB)
avail memory = 3143983104 (2998 MB)
ACPI APIC Table: <7522MS A7522100>
FreeBSD/SMP: Multiprocessor System Detected: 8 CPUs
 cpu0 (BSP): APIC ID:  0
 cpu1 (AP): APIC ID:  1
 cpu2 (AP): APIC ID:  2
 cpu3 (AP): APIC ID:  3
 cpu4 (AP): APIC ID:  4
 cpu5 (AP): APIC ID:  5
 cpu6 (AP): APIC ID:  6
 cpu7 (AP): APIC ID:  7

is a bit in conflict with this:

> kern.sched.topology_spec: <groups>
>  <group level="1" cache-level="0">
>   <cpu count="8" mask="0xff">0, 1, 2, 3, 4, 5, 6, 7</cpu>
>   <flags></flags>
>  </group>
> </groups>

From what I know of its architecture i7 has hyperthreading - i.e. the
CPU has 4 "real" cores which are hyperthreaded, so you get 8 cores
total. It probably also includes a different way of enumerating its
topology which might have caused wrong topology detection and your
slowdown in buildworld. (the CPU also has L3 cache, but I think it's not
looked up in topology detection).

I don't know it this particular error could be responsible for your
lockups - probably not. The CPU also introduces some big changes in
power management (dynamic powerdown of individual cores) which could
cause them - but I can't help you there.

Are you sure it's not something trivial like overheating?

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