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-   -   "Maximum number of CPUs" option when compiling kernel (https://www.linuxquestions.org/questions/linux-kernel-70/maximum-number-of-cpus-option-when-compiling-kernel-665065/)

prejudged_fire 08-24-2008 02:22 PM
"Maximum number of CPUs" option when compiling kernel
 
Does that option refer to the maximum number of physical CPUs the kernel will support, or the number of cores it will support?

syg00 08-24-2008 05:29 PM
yes ... :p

Haven't looked at the code for this but I'd be guessing the number of "entities" that processes can be possibly dispatched on. I always make sure it's more than I reckon I'll need.

prejudged_fire 08-24-2008 06:08 PM
Quote:
Originally Posted by syg00 (Post 3258337)
yes ... :p

Haven't looked at the code for this but I'd be guessing the number of "entities" that processes can be possibly dispatched on. I always make sure it's more than I reckon I'll need.
So it's the number of cores then? If so, I was going to set it to 4. I have a dual core CPU, but I could always get a Quad later. But if it's the physical processors, I'd only set it to 2, of course.

syg00 08-24-2008 08:10 PM
There is no (very minor) benefit in setting it to the actual number of processors. I use 8 for everything, unless I need more. Scheduler queues get built for each processor on each (NUMA) node found - they're not built for all the processors you set as the limit. I think that's right, but I haven't actually checked the "early" code.
FWIW Core 2 quad shows up as 4 processors.

prejudged_fire 08-28-2008 06:56 PM
Ok, thank you for the information :D


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