linux/arch/i386/kernel/cpu/proc.c
Venkatesh Pallipadi 95235ca2c2 [CPUFREQ] CPU frequency display in /proc/cpuinfo
What is the value shown in "cpu MHz" of /proc/cpuinfo when CPUs are capable of
changing frequency?

Today the answer is: It depends.
On i386:
SMP kernel - It is always the boot frequency
UP kernel - Scales with the frequency change and shows that was last set.

On x86_64:
There is one single variable cpu_khz that gets written by all the CPUs. So,
the frequency set by last CPU will be seen on /proc/cpuinfo of all the
CPUs in the system. What you see also depends on whether you have constant_tsc
capable CPU or not.

On ia64:
It is always boot time frequency of a particular CPU that gets displayed.

The patch below changes this to:
Show the last known frequency of the particular CPU, when cpufreq is present. If
cpu doesnot support changing of frequency through cpufreq, then boot frequency
will be shown. The patch affects i386, x86_64 and ia64 architectures.

Signed-off-by: Venkatesh Pallipadi<venkatesh.pallipadi@intel.com>
Signed-off-by: Dave Jones <davej@redhat.com>
2005-12-06 19:35:11 -08:00

159 lines
4.8 KiB
C

#include <linux/smp.h>
#include <linux/timex.h>
#include <linux/string.h>
#include <asm/semaphore.h>
#include <linux/seq_file.h>
#include <linux/cpufreq.h>
/*
* Get CPU information for use by the procfs.
*/
static int show_cpuinfo(struct seq_file *m, void *v)
{
/*
* These flag bits must match the definitions in <asm/cpufeature.h>.
* NULL means this bit is undefined or reserved; either way it doesn't
* have meaning as far as Linux is concerned. Note that it's important
* to realize there is a difference between this table and CPUID -- if
* applications want to get the raw CPUID data, they should access
* /dev/cpu/<cpu_nr>/cpuid instead.
*/
static char *x86_cap_flags[] = {
/* Intel-defined */
"fpu", "vme", "de", "pse", "tsc", "msr", "pae", "mce",
"cx8", "apic", NULL, "sep", "mtrr", "pge", "mca", "cmov",
"pat", "pse36", "pn", "clflush", NULL, "dts", "acpi", "mmx",
"fxsr", "sse", "sse2", "ss", "ht", "tm", "ia64", "pbe",
/* AMD-defined */
NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL,
NULL, NULL, NULL, "syscall", NULL, NULL, NULL, NULL,
NULL, NULL, NULL, "mp", "nx", NULL, "mmxext", NULL,
NULL, "fxsr_opt", NULL, NULL, NULL, "lm", "3dnowext", "3dnow",
/* Transmeta-defined */
"recovery", "longrun", NULL, "lrti", NULL, NULL, NULL, NULL,
NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL,
NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL,
NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL,
/* Other (Linux-defined) */
"cxmmx", "k6_mtrr", "cyrix_arr", "centaur_mcr",
NULL, NULL, NULL, NULL,
NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL,
NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL,
NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL,
/* Intel-defined (#2) */
"pni", NULL, NULL, "monitor", "ds_cpl", "vmx", NULL, "est",
"tm2", NULL, "cid", NULL, NULL, "cx16", "xtpr", NULL,
NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL,
NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL,
/* VIA/Cyrix/Centaur-defined */
NULL, NULL, "rng", "rng_en", NULL, NULL, "ace", "ace_en",
NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL,
NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL,
NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL,
/* AMD-defined (#2) */
"lahf_lm", "cmp_legacy", NULL, NULL, NULL, NULL, NULL, NULL,
NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL,
NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL,
NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL,
};
struct cpuinfo_x86 *c = v;
int i, n = c - cpu_data;
int fpu_exception;
#ifdef CONFIG_SMP
if (!cpu_online(n))
return 0;
#endif
seq_printf(m, "processor\t: %d\n"
"vendor_id\t: %s\n"
"cpu family\t: %d\n"
"model\t\t: %d\n"
"model name\t: %s\n",
n,
c->x86_vendor_id[0] ? c->x86_vendor_id : "unknown",
c->x86,
c->x86_model,
c->x86_model_id[0] ? c->x86_model_id : "unknown");
if (c->x86_mask || c->cpuid_level >= 0)
seq_printf(m, "stepping\t: %d\n", c->x86_mask);
else
seq_printf(m, "stepping\t: unknown\n");
if ( cpu_has(c, X86_FEATURE_TSC) ) {
unsigned int freq = cpufreq_quick_get(n);
if (!freq)
freq = cpu_khz;
seq_printf(m, "cpu MHz\t\t: %u.%03u\n",
freq / 1000, (freq % 1000));
}
/* Cache size */
if (c->x86_cache_size >= 0)
seq_printf(m, "cache size\t: %d KB\n", c->x86_cache_size);
#ifdef CONFIG_X86_HT
if (c->x86_max_cores * smp_num_siblings > 1) {
seq_printf(m, "physical id\t: %d\n", phys_proc_id[n]);
seq_printf(m, "siblings\t: %d\n", cpus_weight(cpu_core_map[n]));
seq_printf(m, "core id\t\t: %d\n", cpu_core_id[n]);
seq_printf(m, "cpu cores\t: %d\n", c->booted_cores);
}
#endif
/* We use exception 16 if we have hardware math and we've either seen it or the CPU claims it is internal */
fpu_exception = c->hard_math && (ignore_fpu_irq || cpu_has_fpu);
seq_printf(m, "fdiv_bug\t: %s\n"
"hlt_bug\t\t: %s\n"
"f00f_bug\t: %s\n"
"coma_bug\t: %s\n"
"fpu\t\t: %s\n"
"fpu_exception\t: %s\n"
"cpuid level\t: %d\n"
"wp\t\t: %s\n"
"flags\t\t:",
c->fdiv_bug ? "yes" : "no",
c->hlt_works_ok ? "no" : "yes",
c->f00f_bug ? "yes" : "no",
c->coma_bug ? "yes" : "no",
c->hard_math ? "yes" : "no",
fpu_exception ? "yes" : "no",
c->cpuid_level,
c->wp_works_ok ? "yes" : "no");
for ( i = 0 ; i < 32*NCAPINTS ; i++ )
if ( test_bit(i, c->x86_capability) &&
x86_cap_flags[i] != NULL )
seq_printf(m, " %s", x86_cap_flags[i]);
seq_printf(m, "\nbogomips\t: %lu.%02lu\n\n",
c->loops_per_jiffy/(500000/HZ),
(c->loops_per_jiffy/(5000/HZ)) % 100);
return 0;
}
static void *c_start(struct seq_file *m, loff_t *pos)
{
return *pos < NR_CPUS ? cpu_data + *pos : 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)
{
}
struct seq_operations cpuinfo_op = {
.start = c_start,
.next = c_next,
.stop = c_stop,
.show = show_cpuinfo,
};