linux/arch/s390/kernel/processor.c
Heiko Carstens 8e1023016c [S390] prevent unneccesary loops_per_jiffy recalculation
When the seqfile /proc/cpuinfo gets accesses for each possible cpu
loops_per_jiffy gets recalculated. However its value is only needed
on first access.
In addition loops_per_jiffy should be recalculated when the machine
reports a capability change.

Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2011-01-05 12:47:32 +01:00

97 lines
2.1 KiB
C

/*
* arch/s390/kernel/processor.c
*
* Copyright IBM Corp. 2008
* Author(s): Martin Schwidefsky (schwidefsky@de.ibm.com)
*/
#define KMSG_COMPONENT "cpu"
#define pr_fmt(fmt) KMSG_COMPONENT ": " fmt
#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/smp.h>
#include <linux/seq_file.h>
#include <linux/delay.h>
#include <linux/cpu.h>
#include <asm/elf.h>
#include <asm/lowcore.h>
#include <asm/param.h>
static DEFINE_PER_CPU(struct cpuid, cpu_id);
/*
* cpu_init - initializes state that is per-CPU.
*/
void __cpuinit cpu_init(void)
{
struct cpuid *id = &per_cpu(cpu_id, smp_processor_id());
get_cpu_id(id);
atomic_inc(&init_mm.mm_count);
current->active_mm = &init_mm;
BUG_ON(current->mm);
enter_lazy_tlb(&init_mm, current);
}
/*
* show_cpuinfo - Get information on one CPU for use by procfs.
*/
static int show_cpuinfo(struct seq_file *m, void *v)
{
static const char *hwcap_str[10] = {
"esan3", "zarch", "stfle", "msa", "ldisp", "eimm", "dfp",
"edat", "etf3eh", "highgprs"
};
unsigned long n = (unsigned long) v - 1;
int i;
if (!n) {
s390_adjust_jiffies();
seq_printf(m, "vendor_id : IBM/S390\n"
"# processors : %i\n"
"bogomips per cpu: %lu.%02lu\n",
num_online_cpus(), loops_per_jiffy/(500000/HZ),
(loops_per_jiffy/(5000/HZ))%100);
seq_puts(m, "features\t: ");
for (i = 0; i < 10; i++)
if (hwcap_str[i] && (elf_hwcap & (1UL << i)))
seq_printf(m, "%s ", hwcap_str[i]);
seq_puts(m, "\n");
}
get_online_cpus();
if (cpu_online(n)) {
struct cpuid *id = &per_cpu(cpu_id, n);
seq_printf(m, "processor %li: "
"version = %02X, "
"identification = %06X, "
"machine = %04X\n",
n, id->version, id->ident, id->machine);
}
put_online_cpus();
return 0;
}
static void *c_start(struct seq_file *m, loff_t *pos)
{
return *pos < NR_CPUS ? (void *)((unsigned long) *pos + 1) : NULL;
}
static void *c_next(struct seq_file *m, void *v, loff_t *pos)
{
++*pos;
return c_start(m, pos);
}
static void c_stop(struct seq_file *m, void *v)
{
}
const struct seq_operations cpuinfo_op = {
.start = c_start,
.next = c_next,
.stop = c_stop,
.show = show_cpuinfo,
};