From c3508f8f341f19f6b1c3f854f144540427668151 Mon Sep 17 00:00:00 2001 From: Ravikiran G Thirumalai Date: Sat, 21 Jul 2007 17:10:19 +0200 Subject: [PATCH] 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 Signed-off-by: Andi Kleen Signed-off-by: Linus Torvalds --- fs/proc/proc_misc.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/fs/proc/proc_misc.c b/fs/proc/proc_misc.c index f133afebed7a..bee251cb87c8 100644 --- a/fs/proc/proc_misc.c +++ b/fs/proc/proc_misc.c @@ -507,7 +507,8 @@ static int show_stat(struct seq_file *p, void *v) } seq_printf(p, "intr %llu", (unsigned long long)sum); -#if !defined(CONFIG_PPC64) && !defined(CONFIG_ALPHA) && !defined(CONFIG_IA64) +#ifndef CONFIG_SMP + /* Touches too many cache lines on SMP setups */ for (i = 0; i < NR_IRQS; i++) seq_printf(p, " %u", per_irq_sum[i]); #endif -- 2.20.1