I rebuilt 2.5.44 with the ACPI stuff enabled, and I see 2 cpus in
/proc/cpuinfo:
daedalus@hercules daedalus $ cat /proc/cpuinfo
processor : 0
vendor_id : GenuineIntel
cpu family : 15
model : 2
model name : Intel(R) XEON(TM) CPU 2.20GHz
stepping : 4
cpu MHz : 2200.469
cache size : 512 KB
fdiv_bug : no
hlt_bug : no
f00f_bug : no
coma_bug : no
fpu : yes
fpu_exception : yes
cpuid level : 2
wp : yes
flags : 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 ht tm
bogomips : 4341.76
processor : 1
vendor_id : GenuineIntel
cpu family : 15
model : 2
model name : Intel(R) XEON(TM) CPU 2.20GHz
stepping : 4
cpu MHz : 2200.469
cache size : 512 KB
fdiv_bug : no
hlt_bug : no
f00f_bug : no
coma_bug : no
fpu : yes
fpu_exception : yes
cpuid level : 2
wp : yes
flags : 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 ht tm
bogomips : 4390.91
Also dmesg says:
daedalus@hercules daedalus $ dmesg
1462.55 usecs.
task migration cache decay timeout: 2 msecs.
enabled ExtINT on CPU#0
ESR value before enabling vector: 00000000
ESR value after enabling vector: 00000000
Booting processor 1/1 eip 2000
Initializing CPU#1
masked ExtINT on CPU#1
ESR value before enabling vector: 00000000
ESR value after enabling vector: 00000000
Calibrating delay loop... 4390.91 BogoMIPS
CPU: Before vendor init, caps: 3febfbff 00000000 00000000, vendor = 0
CPU: Trace cache: 12K uops, L1 D cache: 8K
CPU: L2 cache: 512K
CPU: Physical Processor ID: 0
CPU: After vendor init, caps: 3febfbff 00000000 00000000 00000000
Intel machine check reporting enabled on CPU#1.
CPU#1: Intel P4/Xeon Extended MCE MSRs (12) available
CPU#1: Thermal monitoring enabled
CPU: After generic, caps: 3febfbff 00000000 00000000 00000000
CPU: Common caps: 3febfbff 00000000 00000000 00000000
CPU1: Intel(R) XEON(TM) CPU 2.20GHz stepping 04
Total of 2 processors activated (8732.67 BogoMIPS).
And a bit further down...
checking TSC synchronization across 2 CPUs: passed.
Starting migration thread for cpu 0
Bringing up 1
CPU 1 IS NOW UP!
Starting migration thread for cpu 1
CPUS done 4294967295
And down some more we seem to have 4 cpus...
ACPI: Processor [CPU0] (supports C1)
ACPI: Processor [CPU1] (supports C1)
ACPI: Processor [CPU2] (supports C1)
ACPI: Processor [CPU3] (supports C1)
I think with ACPI disabled I had 4 processors listed in /proc/cpuinfo,
but I'll check.
chrisl@vmware.com wrote:
>It seems that /proc/cpuinfo will return the number of logical CPU.
>If the machine has Intel Hyper-Thread enabled, that number is bigger
>than physical CPU number. Usually twice as big.
>
>My question is, what is the reliable way for user space program
>to detect the number of physical CPU in the current machine?
>
>If in it is in the kernel, I can read from cpu_sibling_map[]
>or phys_cpu_id[]. But it seems not easy read that from
>user space.
>
>Of course I can do "gdb /proc/kcore" to get them. But is there
>any better way?
>
>Thanks in advance.
>
>Chris
>
>
>
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This archive was generated by hypermail 2b29 : Thu Oct 31 2002 - 22:00:26 EST