greybus: loopback: provide interface to read all latency data-points
The current loopback code provides the minimum, maximum and average latency values for a given test set. It would be highly useful for user-space to have access to each one of the latency metrics in order to graph outliers. This patch adds a simple character device interface implmenting a read() interface that allows user-space to read out the saved latency metrics which have been stored in a kfifo for this purpose. A module parameter is provided to allow varying the depth of the kfifo in order to allow a user to capture potentially large data sets. This version sets the default depth for the kfifo at 8192 dwords. Signed-off-by: Bryan O'Donoghue <bryan.odonoghue@linaro.org> Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>
This commit is contained in:
Bryan O'Donoghue
Greg Kroah-Hartman
parent
85d678c0be
commit
cbd204b48d
@ -14,6 +14,10 @@
|
||||
#include <linux/delay.h>
|
||||
#include <linux/random.h>
|
||||
#include <linux/sizes.h>
|
||||
#include <linux/cdev.h>
|
||||
#include <linux/fs.h>
|
||||
#include <linux/kfifo.h>
|
||||
|
||||
#include <asm/div64.h>
|
||||
|
||||
#include "greybus.h"
|
||||
@ -31,9 +35,13 @@ struct gb_loopback {
|
||||
u8 version_major;
|
||||
u8 version_minor;
|
||||
|
||||
struct kfifo kfifo;
|
||||
struct mutex mutex;
|
||||
struct task_struct *task;
|
||||
wait_queue_head_t wq;
|
||||
dev_t dev;
|
||||
struct cdev cdev;
|
||||
struct device *device;
|
||||
|
||||
int type;
|
||||
u32 size;
|
||||
@ -49,6 +57,21 @@ struct gb_loopback {
|
||||
u32 error;
|
||||
};
|
||||
|
||||
#define GB_LOOPBACK_FIFO_DEFAULT 8192
|
||||
|
||||
static struct class *loopback_class;
|
||||
static int loopback_major;
|
||||
static const struct file_operations loopback_fops;
|
||||
static DEFINE_IDA(minors);
|
||||
static unsigned kfifo_depth = GB_LOOPBACK_FIFO_DEFAULT;
|
||||
module_param(kfifo_depth, uint, 0444);
|
||||
|
||||
/* Number of minor devices this driver supports */
|
||||
#define NUM_MINORS 256
|
||||
|
||||
/* Maximum size of any one send data buffer we support */
|
||||
#define MAX_PACKET_SIZE (PAGE_SIZE * 2)
|
||||
|
||||
#define GB_LOOPBACK_MS_WAIT_MAX 1000
|
||||
|
||||
/* Define get_version() routine */
|
||||
@ -129,6 +152,7 @@ static void gb_loopback_check_attr(struct gb_loopback *gb)
|
||||
case GB_LOOPBACK_TYPE_PING:
|
||||
case GB_LOOPBACK_TYPE_TRANSFER:
|
||||
case GB_LOOPBACK_TYPE_SINK:
|
||||
kfifo_reset_out(&gb->kfifo);
|
||||
wake_up(&gb->wq);
|
||||
break;
|
||||
default:
|
||||
@ -381,6 +405,7 @@ static void gb_loopback_calculate_stats(struct gb_loopback *gb)
|
||||
|
||||
/* Log latency stastic */
|
||||
gb_loopback_update_stats(&gb->latency, lat);
|
||||
kfifo_in(&gb->kfifo, (unsigned char *)&lat, sizeof(lat));
|
||||
|
||||
/* Log throughput and requests using latency as benchmark */
|
||||
gb_loopback_throughput_update(gb, lat);
|
||||
@ -433,10 +458,12 @@ static int gb_loopback_connection_init(struct gb_connection *connection)
|
||||
{
|
||||
struct gb_loopback *gb;
|
||||
int retval;
|
||||
int minor;
|
||||
|
||||
gb = kzalloc(sizeof(*gb), GFP_KERNEL);
|
||||
if (!gb)
|
||||
return -ENOMEM;
|
||||
gb_loopback_reset_stats(gb);
|
||||
|
||||
gb->connection = connection;
|
||||
connection->private = gb;
|
||||
@ -444,6 +471,13 @@ static int gb_loopback_connection_init(struct gb_connection *connection)
|
||||
if (retval)
|
||||
goto out_free;
|
||||
|
||||
/* Get a minor number */
|
||||
minor = ida_simple_get(&minors, 0, 0, GFP_KERNEL);
|
||||
if (minor < 0) {
|
||||
retval = minor;
|
||||
goto out_free;
|
||||
}
|
||||
|
||||
/* Check the version */
|
||||
retval = get_version(gb);
|
||||
if (retval)
|
||||
@ -457,17 +491,44 @@ static int gb_loopback_connection_init(struct gb_connection *connection)
|
||||
}
|
||||
gb->size_max -= sizeof(struct gb_loopback_transfer_request);
|
||||
|
||||
gb_loopback_reset_stats(gb);
|
||||
/* Allocate kfifo */
|
||||
if (kfifo_alloc(&gb->kfifo, kfifo_depth * sizeof(u32),
|
||||
GFP_KERNEL)) {
|
||||
retval = -ENOMEM;
|
||||
goto out_get_ver;
|
||||
}
|
||||
|
||||
/* Create device entry */
|
||||
gb->dev = MKDEV(loopback_major, minor);
|
||||
cdev_init(&gb->cdev, &loopback_fops);
|
||||
retval = cdev_add(&gb->cdev, gb->dev, 1);
|
||||
if (retval)
|
||||
goto out_cdev;
|
||||
|
||||
gb->device = device_create(loopback_class, &connection->dev, gb->dev,
|
||||
gb, "gb!loopback%d", minor);
|
||||
if (IS_ERR(gb->device)) {
|
||||
retval = PTR_ERR(gb->device);
|
||||
goto out_device;
|
||||
}
|
||||
|
||||
/* Fork worker thread */
|
||||
init_waitqueue_head(&gb->wq);
|
||||
mutex_init(&gb->mutex);
|
||||
gb->task = kthread_run(gb_loopback_fn, gb, "gb_loopback");
|
||||
if (IS_ERR(gb->task)) {
|
||||
retval = PTR_ERR(gb->task);
|
||||
goto out_get_ver;
|
||||
goto out_kfifo;
|
||||
}
|
||||
|
||||
return 0;
|
||||
|
||||
out_device:
|
||||
cdev_del(&gb->cdev);
|
||||
out_cdev:
|
||||
ida_simple_remove(&minors, minor);
|
||||
out_kfifo:
|
||||
kfifo_free(&gb->kfifo);
|
||||
out_get_ver:
|
||||
sysfs_remove_groups(&connection->dev.kobj, loopback_groups);
|
||||
out_free:
|
||||
@ -481,6 +542,11 @@ static void gb_loopback_connection_exit(struct gb_connection *connection)
|
||||
|
||||
if (!IS_ERR_OR_NULL(gb->task))
|
||||
kthread_stop(gb->task);
|
||||
|
||||
cdev_del(&gb->cdev);
|
||||
ida_simple_remove(&minors, MINOR(gb->dev));
|
||||
device_del(gb->device);
|
||||
kfifo_free(&gb->kfifo);
|
||||
sysfs_remove_groups(&connection->dev.kobj, loopback_groups);
|
||||
kfree(gb);
|
||||
}
|
||||
@ -495,6 +561,80 @@ static struct gb_protocol loopback_protocol = {
|
||||
.request_recv = gb_loopback_request_recv,
|
||||
};
|
||||
|
||||
gb_protocol_driver(&loopback_protocol);
|
||||
static int loopback_open(struct inode *inode, struct file *file)
|
||||
{
|
||||
struct cdev *cdev = inode->i_cdev;
|
||||
struct gb_loopback *gb = container_of(cdev, struct gb_loopback, cdev);
|
||||
|
||||
file->private_data = gb;
|
||||
return 0;
|
||||
}
|
||||
|
||||
static ssize_t loopback_read(struct file *file, char __user *buf, size_t count,
|
||||
loff_t *ppos)
|
||||
{
|
||||
struct gb_loopback *gb = file->private_data;
|
||||
size_t fifo_len;
|
||||
int retval;
|
||||
|
||||
if (!count || count%sizeof(u32))
|
||||
return -EINVAL;
|
||||
|
||||
mutex_lock(&gb->mutex);
|
||||
fifo_len = kfifo_len(&gb->kfifo);
|
||||
if (kfifo_to_user(&gb->kfifo, buf, min(fifo_len, count), &retval) != 0)
|
||||
retval = -EIO;
|
||||
mutex_unlock(&gb->mutex);
|
||||
|
||||
return retval;
|
||||
}
|
||||
|
||||
static const struct file_operations loopback_fops = {
|
||||
.owner = THIS_MODULE,
|
||||
.read = loopback_read,
|
||||
.open = loopback_open,
|
||||
.llseek = noop_llseek,
|
||||
};
|
||||
|
||||
static int loopback_init(void)
|
||||
{
|
||||
dev_t dev;
|
||||
int retval;
|
||||
|
||||
loopback_class = class_create(THIS_MODULE, "gb_loopback");
|
||||
if (IS_ERR(loopback_class)) {
|
||||
retval = PTR_ERR(loopback_class);
|
||||
goto error_class;
|
||||
}
|
||||
|
||||
retval = alloc_chrdev_region(&dev, 0, NUM_MINORS, "gb_loopback");
|
||||
if (retval < 0)
|
||||
goto error_chrdev;
|
||||
|
||||
loopback_major = MAJOR(dev);
|
||||
|
||||
retval = gb_protocol_register(&loopback_protocol);
|
||||
if (retval)
|
||||
goto error_gb;
|
||||
|
||||
return 0;
|
||||
|
||||
error_gb:
|
||||
unregister_chrdev_region(dev, NUM_MINORS);
|
||||
error_chrdev:
|
||||
class_destroy(loopback_class);
|
||||
error_class:
|
||||
return retval;
|
||||
}
|
||||
module_init(loopback_init);
|
||||
|
||||
static void __exit loopback_exit(void)
|
||||
{
|
||||
gb_protocol_deregister(&loopback_protocol);
|
||||
unregister_chrdev_region(MKDEV(loopback_major, 0), NUM_MINORS);
|
||||
class_destroy(loopback_class);
|
||||
ida_destroy(&minors);
|
||||
}
|
||||
module_exit(loopback_exit);
|
||||
|
||||
MODULE_LICENSE("GPL v2");
|
||||
|
||||
Loading…
x
Reference in New Issue
Block a user