Otra forma de ver cuántos procesadores están activados es mirar el archivo /var/log/dmesg por ejemplo:
UBUNTU
[ 0.000000] Bootdata ok (command line is root=/dev/hda1 ro locale=es_ES)
[ 0.000000] Linux version 2.6.17-10-generic (root@crested) (gcc version 4.1.2 20060928 (prerelease) (Ubuntu 4.1.1-13ubuntu5)) #2 SMP Fri Oct 13 15:34:39 UTC 2006 (Ubuntu 2.6.17-10.33-generic)
[ 0.000000] BIOS-provided physical RAM map:
[ 0.000000] BIOS-e820: 0000000000000000 - 000000000009fc00 (usable)
[ 0.000000] BIOS-e820: 000000000009fc00 - 00000000000a0000 (reserved)
[ 0.000000] BIOS-e820: 00000000000e6000 - 0000000000100000 (reserved)
[ 0.000000] BIOS-e820: 0000000000100000 - 000000007ffb0000 (usable)
[ 0.000000] BIOS-e820: 000000007ffb0000 - 000000007ffc0000 (ACPI data)
[ 0.000000] BIOS-e820: 000000007ffc0000 - 000000007fff0000 (ACPI NVS)
[ 0.000000] BIOS-e820: 000000007fff0000 - 0000000080000000 (reserved)
[ 0.000000] BIOS-e820: 00000000ff380000 - 0000000100000000 (reserved)
[ 0.000000] DMI 2.3 present.
[ 0.000000] ACPI: RSDP (v000 ACPIAM ) @ 0x00000000000f8a30
[ 0.000000] ACPI: RSDT (v001 A M I OEMRSDT 0x06000609 MSFT 0x00000097) @ 0x000000007ffb0000
[ 0.000000] ACPI: FADT (v002 A M I OEMFACP 0x06000609 MSFT 0x00000097) @ 0x000000007ffb0200
[ 0.000000] ACPI: MADT (v001 A M I OEMAPIC 0x06000609 MSFT 0x00000097) @ 0x000000007ffb0390
[ 0.000000] ACPI: MCFG (v001 A M I OEMMCFG 0x06000609 MSFT 0x00000097) @ 0x000000007ffb0400
[ 0.000000] ACPI: SSDT (v001 OEM_ID OEMTBLID 0x00000001 INTL 0x02002026) @ 0x000000007ffb51c0
[ 0.000000] ACPI: OEMB (v001 A M I AMI_OEM 0x06000609 MSFT 0x00000097) @ 0x000000007ffc0040
[ 0.000000] ACPI: DSDT (v001 AM2ES AM2ES113 0x00000113 INTL 0x02002026) @ 0x0000000000000000
[ 0.000000] Scanning NUMA topology in Northbridge 24
[ 0.000000] Number of nodes 1
[ 0.000000] Node 0 MemBase 0000000000000000 Limit 000000007ffb0000
[ 0.000000] NUMA: Using 63 for the hash shift.
[ 0.000000] Using node hash shift of 63
[ 0.000000] Bootmem setup node 0 0000000000000000-000000007ffb0000
[ 0.000000] On node 0 totalpages: 515593
[ 0.000000] DMA zone: 2591 pages, LIFO batch:0
[ 0.000000] DMA32 zone: 513002 pages, LIFO batch:31
[ 0.000000] ACPI: PM-Timer IO Port: 0x4008
[ 0.000000] ACPI: Local APIC address 0xfee00000
[ 0.000000] ACPI: LAPIC (acpi_id[0x01] lapic_id[0x00] enabled)
[ 0.000000] Processor #0 15:11 APIC version 16
[ 0.000000] ACPI: LAPIC (acpi_id[0x02] lapic_id[0x01] enabled)
[ 0.000000] Processor #1 15:11 APIC version 16
[ 0.000000] ACPI: IOAPIC (id[0x02] address[0xfec00000] gsi_base[0])
[ 0.000000] IOAPIC[0]: apic_id 2, version 17, address 0xfec00000, GSI 0-23
[ 0.000000] ACPI: IOAPIC (id[0x03] address[0xfec10000] gsi_base[24])
[ 0.000000] IOAPIC[1]: apic_id 3, version 17, address 0xfec10000, GSI 24-44
[ 0.000000] ACPI: INT_SRC_OVR (bus 0 bus_irq 0 global_irq 2 dfl dfl)
[ 0.000000] ACPI: INT_SRC_OVR (bus 0 bus_irq 9 global_irq 9 low level)
[ 0.000000] ACPI: IRQ0 used by override.
[ 0.000000] ACPI: IRQ2 used by override.
[ 0.000000] ACPI: IRQ9 used by override.
[ 0.000000] Setting APIC routing to physical flat
[ 0.000000] Using ACPI (MADT) for SMP configuration information
[ 0.000000] Allocating PCI resources starting at 88000000 (gap: 80000000:7f380000)
[ 0.000000] Checking aperture...
[ 0.000000] CPU 0: aperture @ 2230000000 size 32 MB
[ 0.000000] Aperture from northbridge cpu 0 too small (32 MB)
[ 0.000000] No AGP bridge found
[ 0.000000] SMP: Allowing 2 CPUs, 0 hotplug CPUs
[ 0.000000] Built 1 zonelists
[ 0.000000] Kernel command line: root=/dev/hda1 ro locale=es_ES
[ 0.000000] Initializing CPU#0
[ 0.000000] PID hash table entries: 4096 (order: 12, 32768 bytes)
[ 0.000000] Disabling vsyscall due to use of PM timer
[ 0.000000] time.c: Using 3.579545 MHz WALL PM GTOD PM timer.
[ 0.000000] time.c: Detected 2199.998 MHz processor.
[ 21.323892] Console: colour VGA+ 80x25
[ 21.326598] Dentry cache hash table entries: 262144 (order: 9, 2097152 bytes)
[ 21.327864] Inode-cache hash table entries: 131072 (order: 8, 1048576 bytes)
[ 21.343374] Memory: 2052860k/2096832k available (2129k kernel code, 43584k reserved, 1424k data, 188k init)
[ 21.420598] Calibrating delay using timer specific routine.. 4403.27 BogoMIPS (lpj=8806554)
[ 21.420736] Security Framework v1.0.0 initialized
[ 21.420786] SELinux: Disabled at boot.
[ 21.420849] Mount-cache hash table entries: 256
[ 21.421015] CPU: L1 I Cache: 64K (64 bytes/line), D cache 64K (64 bytes/line)
[ 21.421063] CPU: L2 Cache: 512K (64 bytes/line)
[ 21.421109] CPU 0/0(2) -> Node 0 -> Core 0
[ 21.421167] SMP alternatives: switching to UP code
[ 21.421417] checking if image is initramfs... it is
[ 21.898624] Freeing initrd memory: 6257k freed
[ 21.901391] ACPI: Core revision 20060707
[ 21.901872] ACPI: Looking for DSDT ... not found!
[ 21.944684] Using local APIC timer interrupts.
[ 21.990141] result 12499992
[ 21.990186] Detected 12.499 MHz APIC timer.
[ 21.992287] SMP alternatives: switching to SMP code
[ 21.992430] Booting processor 1/2 APIC 0x1
[ 22.002824] Initializing CPU#1
[ 22.080079] Calibrating delay using timer specific routine.. 4400.26 BogoMIPS (lpj=8800531)
[ 22.080086] CPU: L1 I Cache: 64K (64 bytes/line), D cache 64K (64 bytes/line)
[ 22.080087] CPU: L2 Cache: 512K (64 bytes/line)
[ 22.080090] CPU 1/1(2) -> Node 0 -> Core 1
[ 22.080158] AMD Athlon(tm) 64 X2 Dual Core Processor 4200+ stepping 02
[ 22.084082] CPU 1: Syncing TSC to CPU 0.
[ 22.084077] CPU 1: synchronized TSC with CPU 0 (last diff 0 cycles, maxerr 567 cycles)
[ 22.084082] Brought up 2 CPUs
WIFISLAX 2.0 LiveCD
Linux version 2.6.18-rc5 (root@slax) (gcc version 3.4.6) #4 SMP Mon Sep 18 17:58:52 GMT 2006
BIOS-provided physical RAM map:
BIOS-e820: 0000000000000000 - 000000000009fc00 (usable)
BIOS-e820: 000000000009fc00 - 00000000000a0000 (reserved)
BIOS-e820: 00000000000e6000 - 0000000000100000 (reserved)
BIOS-e820: 0000000000100000 - 000000007ffb0000 (usable)
BIOS-e820: 000000007ffb0000 - 000000007ffc0000 (ACPI data)
BIOS-e820: 000000007ffc0000 - 000000007fff0000 (ACPI NVS)
BIOS-e820: 000000007fff0000 - 0000000080000000 (reserved)
BIOS-e820: 00000000ff380000 - 0000000100000000 (reserved)
1151MB HIGHMEM available.
896MB LOWMEM available.
found SMP MP-table at 000ff780
On node 0 totalpages: 524208
DMA zone: 4096 pages, LIFO batch:0
Normal zone: 225280 pages, LIFO batch:31
HighMem zone: 294832 pages, LIFO batch:31
DMI present.
ACPI: RSDP (v000 ACPIAM ) @ 0x000f8a30
ACPI: RSDT (v001 A M I OEMRSDT 0x07000625 MSFT 0x00000097) @ 0x7ffb0000
ACPI: FADT (v002 A M I OEMFACP 0x07000625 MSFT 0x00000097) @ 0x7ffb0200
ACPI: MADT (v001 A M I OEMAPIC 0x07000625 MSFT 0x00000097) @ 0x7ffb0390
ACPI: MCFG (v001 A M I OEMMCFG 0x07000625 MSFT 0x00000097) @ 0x7ffb0400
ACPI: SSDT (v001 OEM_ID OEMTBLID 0x00000001 INTL 0x02002026) @ 0x7ffb52c0
ACPI: OEMB (v001 A M I AMI_OEM 0x07000625 MSFT 0x00000097) @ 0x7ffc0040
ACPI: DSDT (v001 AM2ES AM2ES122 0x00000122 INTL 0x02002026) @ 0x00000000
ACPI: PM-Timer IO Port: 0x4008
ACPI: Local APIC address 0xfee00000
ACPI: LAPIC (acpi_id[0x01] lapic_id[0x00] enabled)
Processor #0 15:11 APIC version 16
ACPI: LAPIC (acpi_id[0x02] lapic_id[0x01] enabled)
Processor #1 15:11 APIC version 16
WARNING: maxcpus limit of 1 reached. Processor ignored.
ACPI: IOAPIC (id[0x02] address[0xfec00000] gsi_base[0])
IOAPIC[0]: apic_id 2, version 17, address 0xfec00000, GSI 0-23
ACPI: IOAPIC (id[0x03] address[0xfec10000] gsi_base[24])
IOAPIC[1]: apic_id 3, version 17, address 0xfec10000, GSI 24-44
ACPI: INT_SRC_OVR (bus 0 bus_irq 0 global_irq 2 dfl dfl)
ACPI: INT_SRC_OVR (bus 0 bus_irq 9 global_irq 9 low level)
ACPI: IRQ0 used by override.
ACPI: IRQ2 used by override.
ACPI: IRQ9 used by override.
Enabling APIC mode: Flat. Using 2 I/O APICs
Using ACPI (MADT) for SMP configuration information
Allocating PCI resources starting at 88000000 (gap: 80000000:7f380000)
Detected 2200.029 MHz processor.
Built 1 zonelists. Total pages: 524208
Kernel command line: max_loop=255 initrd=boot/initrd.gz vga=0x317 maxcpus=1 init=linuxrc load_ramdisk=1 prompt_ramdisk=0 ramdisk_size=4444 root=/dev/ram0 rw BOOT_IMAGE=boot/vmlinuz
mapped APIC to ffffd000 (fee00000)
mapped IOAPIC to ffffc000 (fec00000)
mapped IOAPIC to ffffb000 (fec10000)
Enabling fast FPU save and restore... done.
Enabling unmasked SIMD FPU exception support... done.
Initializing CPU#0
PID hash table entries: 4096 (order: 12, 16384 bytes)
Console: colour dummy device 80x25
Dentry cache hash table entries: 131072 (order: 7, 524288 bytes)
Inode-cache hash table entries: 65536 (order: 6, 262144 bytes)
Memory: 2067796k/2096832k available (4686k kernel code, 27860k reserved, 3450k data, 324k init, 1179328k highmem)
Checking if this processor honours the WP bit even in supervisor mode... Ok.
Calibrating delay using timer specific routine.. 4402.90 BogoMIPS (lpj=8805810)
Security Framework v1.0.0 initialized
Mount-cache hash table entries: 512
CPU: After generic identify, caps: 178bfbff ebd3fbff 00000000 00000000 00002001 00000000 0000001f
CPU: After vendor identify, caps: 178bfbff ebd3fbff 00000000 00000000 00002001 00000000 0000001f
CPU: L1 I Cache: 64K (64 bytes/line), D cache 64K (64 bytes/line)
CPU: L2 Cache: 512K (64 bytes/line)
CPU 0(2) -> Core 0
CPU: After all inits, caps: 178bfbff ebd3fbff 00000000 00000410 00002001 00000000 0000001f
Intel machine check architecture supported.
Intel machine check reporting enabled on CPU#0.
Checking 'hlt' instruction... OK.
SMP alternatives: switching to UP code
Freeing SMP alternatives: 20k freed
ACPI: Core revision 20060707
CPU0: AMD Athlon(tm) 64 X2 Dual Core Processor 4200+ stepping 02
Total of 1 processors activated (4402.90 BogoMIPS).
ENABLING IO-APIC IRQs
..TIMER: vector=0x31 apic1=0 pin1=2 apic2=-1 pin2=-1
Brought up 1 CPUs
Wifislax sólo arranca uno de los dos procesadores en mi AMDX2 4200