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authorRavikiran G Thirumalai <kiran@scalex86.org>2007-07-21 11:10:19 -0400
committerLinus Torvalds <torvalds@woody.linux-foundation.org>2007-07-21 21:37:09 -0400
commitc3508f8f341f19f6b1c3f854f144540427668151 (patch)
treec5a8ccb4d0ba0a1f108a2233d52232387257e8a0 /fs/proc/proc_misc.c
parent2618f86e0010fc6703e77af3613bac7ade46efc6 (diff)
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>
Diffstat (limited to 'fs/proc/proc_misc.c')
-rw-r--r--fs/proc/proc_misc.c3
1 files changed, 2 insertions, 1 deletions
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)
507 } 507 }
508 seq_printf(p, "intr %llu", (unsigned long long)sum); 508 seq_printf(p, "intr %llu", (unsigned long long)sum);
509 509
510#if !defined(CONFIG_PPC64) && !defined(CONFIG_ALPHA) && !defined(CONFIG_IA64) 510#ifndef CONFIG_SMP
511 /* Touches too many cache lines on SMP setups */
511 for (i = 0; i < NR_IRQS; i++) 512 for (i = 0; i < NR_IRQS; i++)
512 seq_printf(p, " %u", per_irq_sum[i]); 513 seq_printf(p, " %u", per_irq_sum[i]);
513#endif 514#endif