We have a request for a fast method of getting CPU and NUMA node IDs
from userspace. This patch implements a getcpu VDSO function,
similar to x86.
Ben suggested we use SPRG3 which is userspace readable. SPRG3 can be
modified by a KVM guest, so we save the SPRG3 value in the paca and
restore it wh
On Mon, 2012-06-25 at 11:55 +1000, Anton Blanchard wrote:
> We had a request for a fast method of getting CPU and NUMA node IDs
> from userspace. Ben suggested we use SPRG3 which is userspace
> readable. This is a quick hack to try that out.
>
> I have a glibc patch to implement sched_getcpu using
We had a request for a fast method of getting CPU and NUMA node IDs
from userspace. Ben suggested we use SPRG3 which is userspace
readable. This is a quick hack to try that out.
I have a glibc patch to implement sched_getcpu using this. Testing
on a POWER7:
baseline: 538 cycles
vdso: 30 cy
