Re: 8.1-PRERELEASE: CPU packages not detected correctly



on 14/07/2010 17:14 Oliver Fromme said the following:
In a machine installed yesterday, 8.1-PRERELEASE doesn't
seem to detect the number of CPU packages vs. cores per
package correctly:

| FreeBSD 8.1-PRERELEASE-20100713 #0: Tue Jul 13 19:51:18 UTC 2010
| [...]
| CPU: Intel(R) Xeon(R) CPU L5408 @ 2.13GHz (2133.42-MHz K8-class CPU)
| Origin = "GenuineIntel" Id = 0x1067a Family = 6 Model = 17 Stepping = 10
| 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=0x40ce3bd<SSE3,DTES64,MON,DS_CPL,VMX,EST,TM2,SSSE3,CX16,xTPR,PDCM,DCA,SSE4.1,XSAVE>
| AMD Features=0x20000800<SYSCALL,LM>
| AMD Features2=0x1<LAHF>
| TSC: P-state invariant
| real memory = 34359738368 (32768 MB)
| avail memory = 33151377408 (31615 MB)
| ACPI APIC Table: <IBM SERBLADE>
| FreeBSD/SMP: Multiprocessor System Detected: 8 CPUs
| FreeBSD/SMP: 1 package(s) x 8 core(s)
| 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
| ioapic1 <Version 2.0> irqs 24-47 on motherboard
| ioapic0 <Version 2.0> irqs 0-23 on motherboard

I'm pretty sure that this is a 2 x 4 machine (2 CPU packages
with 4 cores per package), not 1 x 8. That's what the BIOS
displays during POST.

I'm not sure if this is just a "cosmetic" issue, or if this
is a critical thing ... I could imagine that performance
might be sub-optimal if the CPU topology isn't detected
correctly, but I'm not sure if FreeBSD can take advantage
of the topology.

Could you please try to do the following?
1. Fetch topo-12212009.tar from the top of this page:
http://software.intel.com/en-us/articles/intel-64-architecture-processor-topology-enumeration/
2. Untar it and apply this patch to the code:
http://people.freebsd.org/~avg/cpu-topology.diff
3. Compile it by running sh mk_64.sh (supposing you have amd64 system installed)
4. Run cpu_topology64.out and report back its output.

Thanks!

--
Andriy Gapon
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