Messages in this thread Patch in this message | | | Date | Thu, 12 Jul 2007 17:06:16 -0700 | From | Ravikiran G Thirumalai <> | Subject | [patch] x86_64: Avoid too many remote cpu references due to /proc/stat |
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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>
Index: linux-2.6.22/fs/proc/proc_misc.c =================================================================== --- linux-2.6.22.orig/fs/proc/proc_misc.c 2007-07-12 16:31:02.000000000 -0700 +++ linux-2.6.22/fs/proc/proc_misc.c 2007-07-12 16:33:45.226221759 -0700 @@ -498,7 +498,8 @@ 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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