Only one CPU is used and shutdown/restart do not work. Perhaps of note is that the rt variant does not set CONFIG_NR_CPU which is set to 64 in 2.6.27-7-generic and 8 in the old 2.6.24-21-rt and also does not set CONFIG_SMP which set to y on the others.
After booting 2.6.27-3-rt dmesg contains this line:
[ 0.000000] WARNING: NR_CPUS limit of 1 reached. Processor ignored.
Compared to booting the non-rt 2.6.27-7-generic:
[ 0.000000] SMP: Allowing 2 CPUs, 0 hotplug CPUs
[ 0.000000] PERCPU: Allocating 64928 bytes of per cpu data
[ 0.000000] NR_CPUS: 64, nr_cpu_ids: 2, nr_node_ids 1
I hope I'm not stepping on toes reopening this. I wasn't able to find guidelines about already closed reports.
Using the linux-rt 2.6.27-3.8 released yesterday I still have at least some of the issues listed in the above comment by Luke Yelavich (https:/ /bugs.launchpad .net/ubuntu/ +source/ linux-rt/ +bug/281276/ comments/ 6).
Only one CPU is used and shutdown/restart do not work. Perhaps of note is that the rt variant does not set CONFIG_NR_CPU which is set to 64 in 2.6.27-7-generic and 8 in the old 2.6.24-21-rt and also does not set CONFIG_SMP which set to y on the others.
After booting 2.6.27-3-rt dmesg contains this line:
[ 0.000000] WARNING: NR_CPUS limit of 1 reached. Processor ignored.
Compared to booting the non-rt 2.6.27-7-generic:
[ 0.000000] SMP: Allowing 2 CPUs, 0 hotplug CPUs
[ 0.000000] PERCPU: Allocating 64928 bytes of per cpu data
[ 0.000000] NR_CPUS: 64, nr_cpu_ids: 2, nr_node_ids 1