tree 521f206229832f757c0f7652101d187a7a6ff5c8
parent a0a9983509f45b2225ca87fdcf7b40ea916834ed
author Ravikiran G Thirumalai <kiran@scalex86.org> 1184834873 -0700
committer Linus Torvalds <torvalds@woody.linux-foundation.org> 1184864683 -0700

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

Optimize show_stat to collect per-irq information just once.

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.
Considering the fact that we already compute this value per-cpu, we can
save on the remote references as below.

Signed-off-by: Alok N Kataria <alok.kataria@calsoftinc.com>
Signed-off-by: Ravikiran Thirumalai <kiran@scalex86.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>