[LinuxBIOS] Help with meaning of config options.

[Marc Jones]

Steve Isaacs wrote:
> When I look at the options passed to the compiler on the command line I
> see the following:
> 
>  -DCONFIG_MAX_CPUS='4' -DCONFIG_MAX_PHYSICAL_CPUS='2'
> -DCONFIG_LOGICAL_CPUS='1'
> 
> Can someone help me understand what the difference between these is? I'm
> working with two dual core opterons and this doesn't seem right to me.
> 
> Steve
> 
> 
> 


CONFIG_MAX_CPUS :  Saves space in the ACPI tables and additional stack 
space for maximum possible number of cores in the system. Might be 
better named as CONFIG_MAX_CPUs_CORES (AMD only)

CONFIG_MAX_PHYSICAL_CPUS: Used to set memory SPD addresses and in 
coherent HyperTransport initialization (AMD only)

CONFIG_LOGICAL_CPUS : This is the flag to build in multi-core support. 
Similar to CONFIG_MAX_CPUS but only set to 0 or 1. (Used by AMD and 
Intel code)

Your setup:
CONFIG_MAX_CPUS : 4  - 4 cores
CONFIG_MAX_PHYSICAL_CPUS: 2 - 2 CPUs
CONFIG_LOGICAL_CPUS : 1 - build multi core support in.


Marc

-- 
Marc Jones
Senior Firmware Engineer
(970) 226-9684 Office
mailto:Marc.Jones at amd.com
http://www.amd.com/embeddedprocessors