This patch adds debugfs node to measure transition of frequency on runtime.
It will be creted under '/sys/kernel/debugfs/devfreq/'dev name'/' as the name
of 'trans_table'. It contains number of transition of each frequency level,
time spent on each level, and also total transition count.
It inspired by CPUFREQ's cpufreq_stats method.
<Example of table>
=================================================================================
<freq level #1> <freq level #2> <freq level #3> time spent
* <freq level #1> n12 n13 t1
<freq level #2> n21 n23 t2
<freq level #3> n31 n32 t3
Total transition : N (= n12 + n13 + n21 + n23 + n31 + n32)
==================================================================================
(n12 : Number of transition from level 1 to level 2)
('*' : The last changed frequency when you inspect the node.)
This patch also includes documentation.
Signed-off-by: Jonghwa Lee <jonghwa3....@samsung.com>
---
Documentation/devfreq/transition_status_table | 265 +++++++++++++++++++++++++
drivers/devfreq/devfreq.c | 123 ++++++++++++
include/linux/devfreq.h | 23 +++
3 files changed, 411 insertions(+), 0 deletions(-)
create mode 100644 Documentation/devfreq/transition_status_table
diff --git a/Documentation/devfreq/transition_status_table
b/Documentation/devfreq/transition_status_table
new file mode 100644
index 0000000..8b92391
--- /dev/null
+++ b/Documentation/devfreq/transition_status_table
@@ -0,0 +1,265 @@
+DEVFREQ Transition status table
+=========================================
+
+Copyright (C) 2012 Samsung Electronics
+
+Written by Jonghwa Lee <jonghwa3....@samsung.com>
+
+1. Description
+----------------
+
+DEVFREQ Transition status table represents all of transition information up to
now. Transition information
+includes number of transition which has been occured and time spent on the
each of frequencies.
+This implementation is ispired by CPUFREQ's cpufreq_stats method.
+
+<Example of table>
+============================================================================================================
+ <freq level #1> <freq level #2> <freq
level #3> time spent
+
+* <freq level #1> Number of transition Number
of transition t1
+ from freq1 to freq2 from
freq1 to freq3
+
+ <freq level #2> Number of transition Number
of transition t2
+ from freq2 to freq1 from
freq2 to freq3
+
+ <freq level #3> Number of transition Number of transition
t3
+ from freq3 to freq1 from freq3 to freq2
+
+Total transition : N
+=============================================================================================================
+('*' : The last changed frequency when you inspect the node.)
+
+It may be used for measuring performance or debug use.
+
+
+2. Requirement to use
+-----------------------
+
+There is no kernel configuration option for creating this node at this moment.
Only CONFIG_DEBUG_FS is required.
+It will be created automatically when devfreq device created successfully.
+(under /sys/kernel/debug/devfreq/'each devfreq device name'/ by the name of
'trans_table'.)
+
+By the way, it's going to show nothing unless you go through the below steps.
+To show appropriate information about frequency transition, each devfreq
device must hand over their own list of
+available frequency and total count of frequency levels to the framework.
Because at the devfreq core side,
+system doesn't know how many freqeuncy levels are available and what value of
each level exactly is.
+In devfreq_dev_profile structure, freq_list and freq_levs will play the role
carrying the those requirement data.
+
+To guarantee trans_table working, following two steps are required.
+(1) Initialize the freq_list of devfreq_dev_profile with all available
freqeuncy data
+(2) Initialize the freq_levs of devfreq_dev_profile with total number of
available freqeuncy level.
+
+3. Guage performance
+----------------------
+
+This program is user space program that measures the frequency transition
during the certain interval you set.
+When the program starts, it parses the trans_table contents and stores it for
later comparison at the end.
+And when you stop the gauging, the program will calculate transition
information happened during the interval given.
+The result is also formed like transition status table. However it can be used
for more specific purpose and usefully
+than trans_table itself. By analyzing its data, we can get an indicator of
performance of various situations or
+performance of governor and others also.
+
+HOW TO USE
+-----------
+1. Set the device name correctly in the code to the variable 'dev_name[]'
before the compile.
+ This will be used to get the path of debugfs node. (Default is
'exynos4412-busfreq').
+2. Run the program, and you'll see comments of '### Press any key to start,
'q' to exit >>' or error massage.
+3. Input any key then it starts measurement with comments 'Gauging start...'
and '### Press any key....'.
+4. Press any key again. It shows the result of measurement directly.
+5. Program will repeat step 2.
+
+<guage_devfreq.c>
+------------------
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <fcntl.h>
+#include <errno.h>
+#include <string.h>
+#include <termios.h>
+
+#define EXTRA_LINE 3
+#define SEC_TO_MSEC 1000
+
+/* FIXME :
+ * Before compile this program,
+ * you shoud fix dev_name[] with device name
+ * which will be tested.
+ */
+/* for exynos4412 */
+char dev_name[] = "exynos4412-busfreq";
+
+struct trans_info {
+ unsigned int max_state;
+ unsigned int *freq;
+ unsigned int *trans_table;
+ unsigned long *time_in_state;
+};
+
+int parse_status(char *fpath, struct trans_info *info)
+{
+ int i, j;
+ char buf[256];
+ unsigned int ntrans;
+ unsigned long time;
+ int max_state = info->max_state;
+ FILE *fp;
+
+ fp = fopen(fpath, "r");
+ if (fp == NULL) {
+ printf("ERR: Coudn't open the file. \n");
+ return -EINVAL;
+ }
+ if(!info->freq[0]) {
+ /* Init freq array with presented frequency */
+ fgets(buf, 256, fp);
+ fgets(buf, 11, fp);
+
+ for (i = 0; i < max_state; i++)
+ fscanf(fp, "%8d",&info->freq[i]);
+
+ fgets(buf, 13, fp);
+ } else {
+ /* Already initialized freq array. Ignore header */
+ fgets(buf, 256, fp);
+ fgets(buf, 256, fp);
+ }
+ for (i = 0; i < max_state; i++) {
+ fgets(buf, 11, fp);
+ for(j = 0; j < max_state; j++) {
+ fscanf(fp, "%8u",&ntrans);
+ info->trans_table[(max_state * i) + j] =
+ ntrans - info->trans_table[(max_state * i) + j];
+ }
+ fscanf(fp, "%10lu", &time);
+ info->time_in_state[i] = time - info->time_in_state[i];
+ fgetc(fp);
+ }
+
+ return 0;
+}
+
+void show_table(struct trans_info *info)
+{
+ int i, j;
+ unsigned long total_period = 0;
+ int max_state = info->max_state;
+
+ printf("\n\n");
+ for (i = 0; i < (info->max_state / 2) + 1; i++)
+ printf("\t");
+ printf("<Guaging result>\n");
+
+ /* Print table bar */
+ printf(" From : To\n");
+ printf(" :");
+ for (i = 0; i < max_state; i++)
+ printf("%8u", info->freq[i]);
+
+ printf(" time(ms)\n");
+
+ /* Print table entry */
+ for (i = 0; i < max_state; i++) {
+
+ printf("%8u:", info->freq[i]);
+
+ for (j = 0; j < max_state; j++)
+ printf("%8u", info->trans_table[(i *
+ max_state) + j]);
+
+ printf("%10lu\n", info->time_in_state[i]);
+ total_period += info->time_in_state[i];
+ }
+
+
+ printf("Total period : %lu\n", total_period / SEC_TO_MSEC);
+ return;
+}
+
+struct trans_info *trans_info_init(char *fpath)
+{
+ struct trans_info *info;
+ FILE *fp;
+ char buf[256];
+ int cnt = 0;
+
+ fp = fopen(fpath, "r");
+ if (fp == NULL) {
+ fprintf(stderr, "ERROR: Coudn't open the file. \n");
+ exit(errno);
+ }
+
+ /* Count number of lines in table */
+ while (fgets(buf, 256, fp)) {
+ cnt++;
+ }
+
+ info = malloc(sizeof(struct trans_info));
+ info->max_state = cnt - EXTRA_LINE;
+ info->freq = malloc(sizeof(unsigned int) * info->max_state);
+ info->trans_table = malloc(sizeof(unsigned int) * info->max_state
+ * info->max_state);
+ info->time_in_state = malloc(sizeof(unsigned long) * info->max_state);
+
+ fclose(fp);
+
+ return info;
+}
+
+int getch()
+{
+ struct termios oldt, newt;
+ int ch;
+
+ tcgetattr(STDIN_FILENO, &oldt);
+ newt = oldt;
+ newt.c_lflag &= ~(ICANON | ECHO);
+ tcsetattr(STDIN_FILENO, TCSANOW, &newt);
+ ch = getchar();
+ tcsetattr(STDIN_FILENO, TCSANOW, &oldt);
+ return ch;
+}
+
+int main(int argc, char **argv) {
+
+ FILE *fp;
+ struct trans_info *info;
+ char ch, fpath[256];
+ int res;
+
+ strcpy(fpath, "/sys/class/devfreq/");
+ strcat(fpath, dev_name);
+ strcat(fpath, "/trans_stat");
+
+ info = trans_info_init(fpath);
+ if (info == NULL) {
+ fprintf(stderr, "ERROR: Initialization failed\n");
+ exit(errno);
+ }
+
+ printf("### Press any key to start, 'q' to exit >>");
+ ch = getch();
+ if (ch == 'q') {
+ printf("\n\nFinish the guaging....\n");
+ return 0;
+ } else {
+ printf("\nGuaging start...\n");
+ printf("### Press any key to stop guaging >>");
+
+ /* Parse trans_stat */
+ res = parse_status(fpath, info);
+ if (res)
+ return res;
+
+ ch = getch();
+ /* Re-Parse trans_stat after duration */
+ res = parse_status(fpath, info);
+ if (res)
+ return res;
+
+ show_table(info);
+ }
+
+ return 0;
+}
diff --git a/drivers/devfreq/devfreq.c b/drivers/devfreq/devfreq.c
index b146d76..6012b09 100644
--- a/drivers/devfreq/devfreq.c
+++ b/drivers/devfreq/devfreq.c
@@ -27,6 +27,8 @@
#include <linux/hrtimer.h>
#include "governor.h"
+#include <linux/debugfs.h>
+
struct class *devfreq_class;
/*
@@ -46,6 +48,8 @@ static struct devfreq *wait_remove_device;
static LIST_HEAD(devfreq_list);
static DEFINE_MUTEX(devfreq_list_lock);
+static struct dentry *devfreq_debugfs;
+
/**
* find_device_devfreq() - find devfreq struct using device pointer
* @dev: device pointer used to lookup device devfreq.
@@ -72,6 +76,40 @@ static struct devfreq *find_device_devfreq(struct device
*dev)
return ERR_PTR(-ENODEV);
}
+int devfreq_get_freq_level(struct devfreq *devfreq, unsigned long freq)
+{
+ int lev;
+
+ for (lev = 0; lev < devfreq->profile->freq_levs; lev++)
+ if (freq == devfreq->profile->freq_list[lev])
+ return lev;
+
+ return -EINVAL;
+}
+
+int devfreq_update_status(struct devfreq *devfreq, unsigned long freq)
+{
+ int lev, prev_lev;
+ unsigned long cur_time;
+
+ prev_lev = devfreq_get_freq_level(devfreq, devfreq->previous_freq);
+ if (prev_lev < 0)
+ return lev;
+
+ cur_time = jiffies;
+ devfreq->time_in_state[prev_lev] +=
+ cur_time - devfreq->last_trinfo_updated;
+ if (freq != devfreq->previous_freq) {
+ lev = devfreq_get_freq_level(devfreq, freq);
+ devfreq->trans_table[(prev_lev *
+ devfreq->profile->freq_levs) + lev]++;
+ devfreq->total_trans++;
+ }
+ devfreq->last_trinfo_updated = cur_time;
+
+ return 0;
+}
+
/**
* update_devfreq() - Reevaluate the device and configure frequency.
* @devfreq: the devfreq instance.
@@ -116,6 +154,11 @@ int update_devfreq(struct devfreq *devfreq)
if (err)
return err;
+ if (devfreq->profile->freq_list)
+ if (devfreq_update_status(devfreq, freq))
+ dev_err(&devfreq->dev,
+ "Couldn't update frequency transition
information.\n");
+
devfreq->previous_freq = freq;
return err;
}
@@ -179,6 +222,8 @@ static void _remove_devfreq(struct devfreq *devfreq, bool
skip)
devfreq->being_removed = true;
+ debugfs_remove_recursive(devfreq->debugfs);
+
if (devfreq->profile->exit)
devfreq->profile->exit(devfreq->dev.parent);
@@ -336,6 +381,59 @@ static void devfreq_monitor(struct work_struct *work)
}
}
+static ssize_t show_trans_table(struct file *file, char __user *user_buf,
+ size_t count, loff_t *ppos)
+{
+ char *buf = kmalloc(PAGE_SIZE, GFP_KERNEL);
+ struct devfreq *devfreq = file->private_data;
+ ssize_t len = 0;
+ int i, j, err;
+ unsigned int freq_levs = devfreq->profile->freq_levs;
+
+ err = devfreq_update_status(devfreq, devfreq->previous_freq);
+ if (err)
+ return 0;
+
+ len = snprintf(buf, PAGE_SIZE, " From : To\n");
+ len += snprintf(buf + len, PAGE_SIZE - len, " :");
+ for (i = 0; i < freq_levs; i++)
+ len += snprintf(buf + len, PAGE_SIZE - len, "%8u",
+ devfreq->profile->freq_list[i]);
+
+ len += snprintf(buf + len, PAGE_SIZE - len, " time(ms)\n");
+
+ for (i = 0; i < freq_levs; i++) {
+ if (devfreq->profile->freq_list[i]
+ == devfreq->previous_freq) {
+ len += snprintf(buf + len, PAGE_SIZE - len, "*");
+ } else {
+ len += snprintf(buf + len, PAGE_SIZE - len, " ");
+ }
+ len += snprintf(buf + len, PAGE_SIZE - len, "%8u:",
+ devfreq->profile->freq_list[i]);
+ for (j = 0; j < freq_levs; j++)
+ len += snprintf(buf + len, PAGE_SIZE - len, "%8u",
+ devfreq->trans_table[(i * freq_levs) + j]);
+ len += snprintf(buf + len, PAGE_SIZE - len, "%10u\n",
+ jiffies_to_msecs(devfreq->time_in_state[i]));
+ }
+
+ len += snprintf(buf + len, PAGE_SIZE - len, "Total transition : %u\n",
+ devfreq->total_trans);
+
+ len = simple_read_from_buffer(user_buf, count, ppos, buf, len);
+
+ kfree(buf);
+
+ return len;
+}
+
+static const struct file_operations devfreq_trans_table_fops = {
+ .open = simple_open,
+ .read = show_trans_table,
+ .llseek = default_llseek,
+};
+
/**
* devfreq_add_device() - Add devfreq feature to the device
* @dev: the device to add devfreq feature.
@@ -390,6 +488,15 @@ struct devfreq *devfreq_add_device(struct device *dev,
= msecs_to_jiffies(devfreq->profile->polling_ms);
devfreq->nb.notifier_call = devfreq_notifier_call;
+ devfreq->trans_table = devm_kzalloc(dev, sizeof(unsigned int) *
+ devfreq->profile->freq_levs *
+ devfreq->profile->freq_levs,
+ GFP_KERNEL);
+ devfreq->time_in_state = devm_kzalloc(dev, sizeof(unsigned int) *
+ devfreq->profile->freq_levs,
+ GFP_KERNEL);
+ devfreq->last_trinfo_updated = jiffies;
+
dev_set_name(&devfreq->dev, dev_name(dev));
err = device_register(&devfreq->dev);
if (err) {
@@ -417,6 +524,16 @@ struct devfreq *devfreq_add_device(struct device *dev,
devfreq->next_polling);
}
mutex_unlock(&devfreq_list_lock);
+
+ mutex_lock(&devfreq->lock);
+ if (!IS_ERR(devfreq_debugfs)) {
+ devfreq->debugfs = debugfs_create_dir(dev_name(dev),
+ devfreq_debugfs);
+ debugfs_create_file("trans_table", S_IRUGO, devfreq->debugfs,
+ devfreq, &devfreq_trans_table_fops);
+ }
+ mutex_unlock(&devfreq->lock);
+
out:
return devfreq;
@@ -623,12 +740,18 @@ static int __init devfreq_init(void)
return PTR_ERR(devfreq_class);
}
devfreq_class->dev_attrs = devfreq_attrs;
+
+ devfreq_debugfs = debugfs_create_dir("devfreq", NULL);
+ if (IS_ERR(devfreq_debugfs))
+ pr_err("%s: couldn't create debugfs\n", __FILE__);
+
return 0;
}
subsys_initcall(devfreq_init);
static void __exit devfreq_exit(void)
{
+ debugfs_remove(devfreq_debugfs);
class_destroy(devfreq_class);
}
module_exit(devfreq_exit);
diff --git a/include/linux/devfreq.h b/include/linux/devfreq.h
index 281c72a..d9cce45 100644
--- a/include/linux/devfreq.h
+++ b/include/linux/devfreq.h
@@ -57,6 +57,10 @@ struct devfreq_dev_status {
* @initial_freq The operating frequency when devfreq_add_device() is
* called.
* @polling_ms The polling interval in ms. 0 disables polling.
+ *
+ * @freq_list List for all availble frequencies in this DEVFREQ.
+ * @freq_levs Total number of frequncy levels.
+ *
* @target The device should set its operating frequency at
* freq or lowest-upper-than-freq value. If freq is
* higher than any operable frequency, set maximum.
@@ -71,11 +75,16 @@ struct devfreq_dev_status {
* from devfreq_remove_device() call. If the user
* has registered devfreq->nb at a notifier-head,
* this is the time to unregister it.
+ *
+ * @
*/
struct devfreq_dev_profile {
unsigned long initial_freq;
unsigned int polling_ms;
+ unsigned int *freq_list;
+ unsigned int freq_levs;
+
int (*target)(struct device *dev, unsigned long *freq, u32 flags);
int (*get_dev_status)(struct device *dev,
struct devfreq_dev_status *stat);
@@ -137,6 +146,12 @@ struct devfreq_governor {
* @min_freq Limit minimum frequency requested by user (0: none)
* @max_freq Limit maximum frequency requested by user (0: none)
*
+ * @total_trans Total trasition number.
+ * @trans_table Transition count of each frequency
level.
+ * @time_in_state Spent time of each freqeuncy level.
+ * @last_trinfo_updated Time mark of last transition
information updating.
+ *
+ * @debgufs
* This structure stores the devfreq information for a give device.
*
* Note that when a governor accesses entries in struct devfreq in its
@@ -164,6 +179,14 @@ struct devfreq {
unsigned long min_freq;
unsigned long max_freq;
+
+ /* information for device freqeuncy transition */
+ unsigned int total_trans;
+ unsigned int *trans_table;
+ unsigned long *time_in_state;
+ unsigned long last_trinfo_updated;
+
+ struct dentry *debugfs;
};
#if defined(CONFIG_PM_DEVFREQ)
--
1.7.4.1
--
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