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tile: support reporting Tilera hypervisor statistics

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Newer hypervisors have an API for reporting per-cpu statistics
information.  This change allows seeing that information via
/sys/devices/system/cpu/cpuN/hv_stats file for each core.

Signed-off-by: Chris Metcalf <cmetcalf@tilera.com>
This commit is contained in:
Chris Metcalf 2013-08-12 14:39:22 -04:00
parent 8157107b13
commit 80f184108e
2 changed files with 89 additions and 3 deletions
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16
arch/tile/include/hv/hypervisor.h
View File

@ -544,14 +544,24 @@ typedef enum {
HV_CONFSTR_CPUMOD_REV = 18,
/** Human-readable CPU module description. */
HV_CONFSTR_CPUMOD_DESC = 19
HV_CONFSTR_CPUMOD_DESC = 19,
/** Per-tile hypervisor statistics. When this identifier is specified,
* the hv_confstr call takes two extra arguments. The first is the
* HV_XY_TO_LOTAR of the target tile's coordinates. The second is
* a flag word. The only current flag is the lowest bit, which means
* "zero out the stats instead of retrieving them"; in this case the
* buffer and buffer length are ignored. */
HV_CONFSTR_HV_STATS = 20
} HV_ConfstrQuery;
/** Query a configuration string from the hypervisor.
*
* @param query Identifier for the specific string to be retrieved
* (HV_CONFSTR_xxx).
* (HV_CONFSTR_xxx). Some strings may require or permit extra
* arguments to be appended which select specific objects to be
* described; see the string descriptions above.
* @param buf Buffer in which to place the string.
* @param len Length of the buffer.
* @return If query is valid, then the length of the corresponding string,
@ -559,7 +569,7 @@ typedef enum {
* was truncated. If query is invalid, HV_EINVAL. If the specified
* buffer is not writable by the client, HV_EFAULT.
*/
int hv_confstr(HV_ConfstrQuery query, HV_VirtAddr buf, int len);
int hv_confstr(HV_ConfstrQuery query, HV_VirtAddr buf, int len, ...);
/** Tile coordinate */
typedef struct

76
arch/tile/kernel/sysfs.c
View File

@ -157,6 +157,67 @@ hvconfig_bin_read(struct file *filp, struct kobject *kobj,
return count;
}
static ssize_t hv_stats_show(struct device *dev,
struct device_attribute *attr,
char *page)
{
int cpu = dev->id;
long lotar = HV_XY_TO_LOTAR(cpu_x(cpu), cpu_y(cpu));
ssize_t n = hv_confstr(HV_CONFSTR_HV_STATS,
(unsigned long)page, PAGE_SIZE - 1,
lotar, 0);
n = n < 0 ? 0 : min(n, (ssize_t)PAGE_SIZE - 1);
page[n] = '\0';
return n;
}
static ssize_t hv_stats_store(struct device *dev,
struct device_attribute *attr,
const char *page,
size_t count)
{
int cpu = dev->id;
long lotar = HV_XY_TO_LOTAR(cpu_x(cpu), cpu_y(cpu));
ssize_t n = hv_confstr(HV_CONFSTR_HV_STATS, 0, 0, lotar, 1);
return n < 0 ? n : count;
}
static DEVICE_ATTR(hv_stats, 0644, hv_stats_show, hv_stats_store);
static int hv_stats_device_add(struct device *dev, struct subsys_interface *sif)
{
int err, cpu = dev->id;
if (!cpu_online(cpu))
return 0;
err = sysfs_create_file(&dev->kobj, &dev_attr_hv_stats.attr);
return err;
}
static int hv_stats_device_remove(struct device *dev,
struct subsys_interface *sif)
{
int cpu = dev->id;
if (!cpu_online(cpu))
return 0;
sysfs_remove_file(&dev->kobj, &dev_attr_hv_stats.attr);
return 0;
}
static struct subsys_interface hv_stats_interface = {
.name = "hv_stats",
.subsys = &cpu_subsys,
.add_dev = hv_stats_device_add,
.remove_dev = hv_stats_device_remove,
};
static int __init create_sysfs_entries(void)
{
int err = 0;
@ -188,6 +249,21 @@ static int __init create_sysfs_entries(void)
err = sysfs_create_bin_file(hypervisor_kobj, &hvconfig_bin);
}
if (!err) {
/*
* Don't bother adding the hv_stats files on each CPU if
* our hypervisor doesn't supply statistics.
*/
int cpu = raw_smp_processor_id();
long lotar = HV_XY_TO_LOTAR(cpu_x(cpu), cpu_y(cpu));
char dummy;
ssize_t n = hv_confstr(HV_CONFSTR_HV_STATS,
(unsigned long) &dummy, 1,
lotar, 0);
if (n >= 0)
err = subsys_interface_register(&hv_stats_interface);
}
return err;
}
subsys_initcall(create_sysfs_entries);