Differences between the SMP and BIGSMP Kernels
Novell Cool Solutions: Tip
By Kirk Coombs
Reader Rating 
from 10 ratings
|
Digg This -
Slashdot This
Posted: 25 Oct 2005 |
Applies to:
- SUSE Linux
- SUSE Linux Enterprise Server
Which one to use...
Some people are confused by the differences between the SMP and BIGSMP kernels included in SUSE Linux, and which one to use for their system. A quick look at the build configuration for both kernels shows several differences, but the most significant involves the supported amount of RAM and number of CPUs.
The SMP kernel contains the following parameters:
CONFIG_HIGHMEM4G=y
CONFIG_NR_CPUS=32
Thus allowing a maximum of 4G RAM and 32 processors.
The BIGSMP kernel, however, has these:
CONFIG_HIGHMEM64G=y
CONFIG_NR_CPUS=128
Enabling support for 64G memory and 128 processors.
If a system has either more than 4G RAM or more than 32 processors, the BIGSMP kernel must be used to fully utilize the system.
Reader Comments
- Hinweis auf SLES oder SuSE 9.X/10.X währe hilfreich. (Gilt es für alle SUSE-Kernel?)
- While interesting I still have other questions. Why on a 4GB machine is bigsmp chosen by default even though the machine only has 2 physical CPUs? Why on a machine with 2GB RAM when we upgrade to 4GB is only 3GB and a bit seen, when you say support is there for 4GB? What is the highmem/lowmem split for each of these kernels?
- Is this only for the 32-bit kernel or both 32/64-bit
- Looking at the related package descriptions the bigsmp kernel is suitable for 32 Bit architectures only. Is that true? If yes : What is to be done on 64Bit architectures to get PAE support?
- Need to distinguish 32-bit and 64-bit.....
- how about an instruction how to switch between kernels (e.g. after installing more RAM)?
Novell Cool Solutions (corporate web communities) are produced by WebWise Solutions. www.webwiseone.com