From: Ravikiran G Thirumalai Date: Sat, 21 Jul 2007 15:10:19 +0000 (+0200) Subject: x86_64: Avoid too many remote cpu references due to /proc/stat X-Git-Tag: v2.6.23-rc1~119 X-Git-Url: https://err.no/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=c3508f8f341f19f6b1c3f854f144540427668151;p=linux-2.6 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 --- diff --git a/fs/proc/proc_misc.c b/fs/proc/proc_misc.c index f133afebed..bee251cb87 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