Re: Intel Atom N450 & Kernel Config Options re: SMP
Arthur Machlas put forth on 7/28/2010 11:14 PM:
> Greetings,
>
> According to the spec sheet on the Atom N450 it has a single core,
> though it does support two threads. However, linuxinfo (replaces
> cpuinfo I suppose) says two unknown processors.
Your kernel doesn't either doesn't support CPU_ID or doesn't have the tables
for Atom CPUs, or both. This is a kernel config option.
> root@HPm210:/home/arthur/Misc/Linux/2.6.34-1# linuxinfo
> Linux HPm210 2.6.32-5-686 #1 SMP Tue Jun 1 04:59:47 UTC 2010
> Two Intel Unknown 1666MHz processors, 6650.42 total bogomips, 1011M RAM
> Strangely, that's not the correct amount of ram in the system.
Strangely, most people don't rely on linuxinfo. ;) File a bug report.
> root@HPm210:/home/arthur/Misc/Linux/2.6.34-1# free -m
> total used free shared buffers cached
> Mem: 2014 1377 636 0 6 1186
> -/+ buffers/cache: 184 1830
> Swap: 1972 0 1971
>
> Anyway, as you can see from the current directory, the reason I'm
> asking about the number of cpu's cores in the atom n450 is that I'm
> rolling my own kernel hoping a newer version will be able to get the
> freq down to 800mhz same as windows, currently reporting that it can
> only go as low as 1000. Also want to optimize for the atom processor
> and build in all modules needed for hardware.
In "make menuconfig":
In "Processor Type and Features"
uncheck Symmetric multi-processing support
check Intel Atom in "Processor Family"
check SMT (HyperThreading)
uncheck Multi-core scheduler support
check Intel MCE features
check /dev/cpu/*/msr - Model-specific register support
check /dev/cpu/*/cpuid - CPU information support
These last two are probably the reason for the "unknown", especially given
you're running 2.6.34 which has all the CPU models currently on the market.
In "Power management and ACPI options"
select "CPU Frequency scaling"
check CPU Frequency scaling (not a dup typo)
read the descriptions and decide which is the best default governor for you
then select the "CPUFreq processor drivers" that matches your hardware platform
You'll have to figure out all the other menu config settings on your own, as
most of us kernel monkeys have. ;) These are simply the ones that directly
relate to your questions.
Hope this helped get you closer.
--
Stan
Reply to: