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: NAlok N Kataria <alok.kataria@calsoftinc.com> Signed-off-by: NRavikiran Thirumalai <kiran@scalex86.org> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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