New CPU, enable SMP

[Weaseal]

Hi all,
I just replaced my AMD Athlon64 3500+ (single core) with a dual-core 4200+. Do I have to do anything to get FreeBSD to access the extra core? I made sure options SMP is enabled in the kernel config.

Is there a way to dynamically check to see how many cores it recognizes?

[ale]

Check with sysctl hw.ncpu

[DutchDaemon]

And also top -P should show how many CPUs are used (and how).

[Weaseal]

$ sysctl hw.ncpu
hw.ncpu: 1

$ dmesg | grep -i cpu
CPU: AMD Athlon(tm) 64 Processor 4200+ (2200.10-MHz K8-class CPU)
cpu0: <ACPI CPU> on acpi0
powernow0: <Cool`n'Quiet K8> on cpu0
acpi_throttle0: <ACPI CPU Throttling> on cpu0What gives?

[kamikaze]

Maybe the second core is deactivated in the BIOS. In FreeBSD 7.1 the default kernel is an SMP kernel, so you do not have to activate anything.

[Weaseal]

I have read somewhere online that some motherboards require you to flash the BIOS when replacing a CPU (especially if you are adding cores)... could this be it?

I'll double-check the BIOS.

[kamikaze]

It might be that the CPU was not available when your motherboard was built and you require a new BIOS version.

[cpcnw]

I'd like to attempt a custom kernel on my X2 - currently ;


$ cat /var/run/dmesg.boot | grep CPU
CPU: AMD Athlon(tm) 64 X2 Dual Core Processor 5200+ (2700.27-MHz 686-class CPU)
FreeBSD/SMP: Multiprocessor System Detected: 2 CPUs
cpu0: <ACPI CPU> on acpi0
cpu1: <ACPI CPU> on acpi0
SMP: AP CPU #1 Launched!


and


$ top -P [sniped]
CPU 0: 0.0% user, 0.0% nice, 0.0% system, 0.0% interrupt, 100% idle
CPU 1: 0.4% user, 0.0% nice, 0.0% system, 0.0% interrupt, 99.6% idle


Is CPU0 even used? And is all that is required is to leave in my KERNCONF;


options SMP # Symmetric MultiProcessor Kernel
device apic # I/O APIC