tree c5a8ccb4d0ba0a1f108a2233d52232387257e8a0
parent 2618f86e0010fc6703e77af3613bac7ade46efc6
author Ravikiran G Thirumalai <kiran@scalex86.org> 1185030619 +0200
committer Linus Torvalds <torvalds@woody.linux-foundation.org> 1185068229 -0700

x86_64: Avoid too many remote cpu references due to /proc/stat

Too many remote cpu references due to /proc/stat.

On x86_64, with newer kernel versions, kstat_irqs is a bit of a problem.
On every call to kstat_irqs, the process brings in per-cpu data from all
online cpus.  Doing this for NR_IRQS, which is now 256 + 32 * NR_CPUS
results in (256+32*63) * 63 remote cpu references on a 64 cpu config.
/proc/stat is parsed by common commands like top, who etc, causing lots
of cacheline transfers

This statistic seems useless.  Other 'big iron' arches disable this.

AK: changed to remove for all SMP setups
AK: add comment

Signed-off-by: Ravikiran Thirumalai <kiran@scalex86.org>
Signed-off-by: Andi Kleen <ak@suse.de>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>