On 03/21/2017 09:05 PM, Ray Mansell wrote: > We've been running some beefy Debian servers, but of course one of them > was not beefy enough, and we were asked if we could increase the number > of CPUs from 32 to 48. Easy, I thought, until I rebooted the beefier > server only to discover it had restricted itself to 32 CPUs, even though > it knew 48 were present: > > cpu: 48 configured CPUs, 0 standby CPUs > Brought up 32 CPUs > > The output from uname is: > > uname -a > Linux linux02 3.16.0-4-s390x #1 SMP Debian 3.16.7-ckt9-3 > (2015-04-23) s390x GNU/Linux > > And it is running on a z/VM 6.3 host. > > I've searched through many documents and publications, but haven't been > able to find anything that might help resolve this situation. Can anyone > provide some insight, please?
Looks like the Debian kernel config for 3.16 contains CONFIG-NR_CPUS=32. This probably has made some sense in 31bit times (so that cpumasks in the kernel could fit into a word size) but it looks like it was not increased for 64bit to a higher value. ---------------------------------------------------------------------- For LINUX-390 subscribe / signoff / archive access instructions, send email to lists...@vm.marist.edu with the message: INFO LINUX-390 or visit http://www.marist.edu/htbin/wlvindex?LINUX-390 ---------------------------------------------------------------------- For more information on Linux on System z, visit http://wiki.linuxvm.org/
