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| author | Ravikiran G Thirumalai <kiran@scalex86.org> | 2007-07-21 17:10:19 +0200 |
|---|---|---|
| committer | Linus Torvalds <torvalds@woody.linux-foundation.org> | 2007-07-21 18:37:09 -0700 |
| commit | c3508f8f341f19f6b1c3f854f144540427668151 (patch) | |
| tree | c5a8ccb4d0ba0a1f108a2233d52232387257e8a0 /fs/proc | |
| parent | 2618f86e0010fc6703e77af3613bac7ade46efc6 (diff) | |
| download | op-kernel-dev-c3508f8f341f19f6b1c3f854f144540427668151.zip op-kernel-dev-c3508f8f341f19f6b1c3f854f144540427668151.tar.gz | |
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')
| -rw-r--r-- | fs/proc/proc_misc.c | 3 |
1 files changed, 2 insertions, 1 deletions
diff --git a/fs/proc/proc_misc.c b/fs/proc/proc_misc.c index f133afe..bee251c 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 |
