Re: 2.6.27rc1 cannot boot more than 8CPUs

Max Krasnyansky
2008-08-06T03:31:51Z

Jeff Chua wrote:
> I've a Dell R900 with 4 quad-core Xeon processors (total 16CPUs), but
> can only managed to boot up with CONFIG_NR_CPUS=8. Setting
> CONFIG_NR_CPUS=16 causes the kernel to hang while booting.

You could try booting CONFIG_NR_CPUS=16 with maxcpus=8 (kernel command line
option).

If it boots you can then try bringing the rest of the cpus online manually
echo 1 > /sys/devices/system/cpu/cpu8/online
...
echo 1 > /sys/devices/system/cpu/cpu15/online

Might get a better OOPS/BUG_ON/etc report.

Max