Messages in this thread Patch in this message | | | From | Andi Kleen <> | Subject | [PATCH] [33/58] x86_64: Avoid too many remote cpu references due to /proc/stat | Date | Thu, 19 Jul 2007 11:55:19 +0200 (CEST) |
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From: Ravikiran G Thirumalai <kiran@scalex86.org> 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. Can we disable computing/reporting this statistic? This piece of statistic is not human readable on x86_64 anymore,
If not, can we optimize computing this statistic so as to avoid too many remote references (patch to follow)
Signed-off-by: Ravikiran Thirumalai <kiran@scalex86.org> Signed-off-by: Andi Kleen <ak@suse.de>
--- fs/proc/proc_misc.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-)
Index: linux/fs/proc/proc_misc.c =================================================================== --- linux.orig/fs/proc/proc_misc.c +++ linux/fs/proc/proc_misc.c @@ -499,7 +499,8 @@ static int show_stat(struct seq_file *p, } seq_printf(p, "intr %llu", (unsigned long long)sum); -#if !defined(CONFIG_PPC64) && !defined(CONFIG_ALPHA) && !defined(CONFIG_IA64) +#if !defined(CONFIG_PPC64) && !defined(CONFIG_ALPHA) && !defined(CONFIG_IA64) \ + && !defined(CONFIG_X86_64) for (i = 0; i < NR_IRQS; i++) seq_printf(p, " %u", kstat_irqs(i)); #endif - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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