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Commit 80f18410 authored by Chris Metcalf's avatar Chris Metcalf
Browse files

tile: support reporting Tilera hypervisor statistics 



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: default avatarChris Metcalf <cmetcalf@tilera.com>
parent 8157107b

arch/tile/include/hv/hypervisor.h

+13 −3
Original line number Diff line number Diff line
@@ -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

arch/tile/kernel/sysfs.c

+76 −0
Original line number Diff line number Diff line
@@ -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);