Commit 441cc6f5 authored by Mete Durlu's avatar Mete Durlu Committed by Vasily Gorbik
Browse files

s390/hiperdispatch: Add hiperdispatch debug attributes 



Add two attributes for debug purposes. They can be found under;
/sys/devices/system/cpu/hiperdispatch/
* hd_stime_threshold : allows user to adjust steal time threshold
* hd_delay_factor : allows user to adjust delay factor of hiperdispatch
                    work (after topology updates, delayed work is
                    always delayed extra by this factor)

hd_stime_threshold can have values between 0-100 as it represents a
percentage value.
hd_delay_factor can have values greater than 1. It is multiplied with
the default delay to achieve a longer interval, pushing back the next
hiperdispatch adjustment after a topology update.

Ex:
if delay interval is 250ms and the delay factor is 4;
delayed interval is now 1000ms(1sec). After each capacity adjustment
or topology change, work has a delayed interval of 1 sec for one
interval.

Acked-by: default avatarVasily Gorbik <gor@linux.ibm.com>
Signed-off-by: default avatarMete Durlu <meted@linux.ibm.com>
Signed-off-by: default avatarVasily Gorbik <gor@linux.ibm.com>
parent b9271a53

arch/s390/kernel/hiperdispatch.c

+82 −2
Original line number Diff line number Diff line
@@ -46,7 +46,9 @@ 
 */



#include <linux/cpumask.h>

#include <linux/device.h>

#include <linux/kernel_stat.h>

#include <linux/kstrtox.h>

#include <linux/ktime.h>

#include <linux/sysctl.h>

#include <linux/workqueue.h>
@@ -71,6 +73,8 @@ static int hd_online_cores; /* Current online CORE count */ 


static unsigned long hd_previous_steal;	/* Previous iteration's CPU steal timer total */



static unsigned int hd_steal_threshold = HD_STEAL_THRESHOLD;

static unsigned int hd_delay_factor = HD_DELAY_FACTOR;

static int hd_enabled;



static void hd_capacity_work_fn(struct work_struct *work);
@@ -151,7 +155,7 @@ int hd_enable_hiperdispatch(void) 
		return 0;

	if (hd_online_cores <= hd_entitled_cores)

		return 0;

	mod_delayed_work(system_wq, &hd_capacity_work, HD_DELAY_INTERVAL * HD_DELAY_FACTOR);

	mod_delayed_work(system_wq, &hd_capacity_work, HD_DELAY_INTERVAL * hd_delay_factor);

	hd_update_capacities();

	return 1;

}
@@ -214,7 +218,7 @@ static void hd_capacity_work_fn(struct work_struct *work) 
		return;

	}

	steal_percentage = hd_steal_avg(hd_calculate_steal_percentage());

	if (steal_percentage < HD_STEAL_THRESHOLD)

	if (steal_percentage < hd_steal_threshold)

		new_cores = hd_online_cores;

	else

		new_cores = hd_entitled_cores;
@@ -260,6 +264,81 @@ static struct ctl_table hiperdispatch_ctl_table[] = { 
	},

};



static ssize_t hd_steal_threshold_show(struct device *dev,

				       struct device_attribute *attr,

				       char *buf)

{

	return sysfs_emit(buf, "%u\n", hd_steal_threshold);

}



static ssize_t hd_steal_threshold_store(struct device *dev,

					struct device_attribute *attr,

					const char *buf,

					size_t count)

{

	unsigned int val;

	int rc;



	rc = kstrtouint(buf, 0, &val);

	if (rc)

		return rc;

	if (val > 100)

		return -ERANGE;

	hd_steal_threshold = val;

	return count;

}



static DEVICE_ATTR_RW(hd_steal_threshold);



static ssize_t hd_delay_factor_show(struct device *dev,

				    struct device_attribute *attr,

				    char *buf)

{

	return sysfs_emit(buf, "%u\n", hd_delay_factor);

}



static ssize_t hd_delay_factor_store(struct device *dev,

				     struct device_attribute *attr,

				     const char *buf,

				     size_t count)

{

	unsigned int val;

	int rc;



	rc = kstrtouint(buf, 0, &val);

	if (rc)

		return rc;

	if (!val)

		return -ERANGE;

	hd_delay_factor = val;

	return count;

}



static DEVICE_ATTR_RW(hd_delay_factor);



static struct attribute *hd_attrs[] = {

	&dev_attr_hd_steal_threshold.attr,

	&dev_attr_hd_delay_factor.attr,

	NULL,

};



static const struct attribute_group hd_attr_group = {

	.name  = "hiperdispatch",

	.attrs = hd_attrs,

};



static void __init hd_create_attributes(void)

{

	struct device *dev;



	dev = bus_get_dev_root(&cpu_subsys);

	if (!dev)

		return;

	if (sysfs_create_group(&dev->kobj, &hd_attr_group))

		pr_warn("Unable to create hiperdispatch attribute group\n");

	put_device(dev);

}



static int __init hd_init(void)

{

	if (IS_ENABLED(CONFIG_HIPERDISPATCH_ON)) {
@@ -268,6 +347,7 @@ static int __init hd_init(void) 
	}

	if (!register_sysctl("s390", hiperdispatch_ctl_table))

		pr_warn("Failed to register s390.hiperdispatch sysctl attribute\n");

	hd_create_attributes();

	return 0;

}

late_initcall(hd_init);