timer

timer/log.txt

@@ -1,23 +1,20 @@
 clang-format-9 -i timer.c
 make -C /lib/modules/5.3.0-26-generic/build M=/home/matthewzorin/Linux_Kernel/gl-kernel-basecamp-2020/timer modules
 make[1]: Entering directory '/usr/src/linux-headers-5.3.0-26-generic'
-  CC [M]  /home/matthewzorin/Linux_Kernel/gl-kernel-basecamp-2020/timer/timer.o
   Building modules, stage 2.
   MODPOST 1 modules
-  LD [M]  /home/matthewzorin/Linux_Kernel/gl-kernel-basecamp-2020/timer/timer.ko
 make[1]: Leaving directory '/usr/src/linux-headers-5.3.0-26-generic'
 sudo insmod timer.ko
 lsmod | head -n 3
 Module                  Size  Used by
 timer                  16384  0
 rfcomm                 81920  4
-inter = 0 s
-delay = 0	inter = 0 s	inter = 9225 s 645643198 ns
-delay = 5	inter = 4 s	inter = 9230 s 651359080 ns
-delay = 10	inter = 9 s	inter = 9240 s 660130462 ns
-delay = 15	inter = 14 s	inter = 9255 s 668047092 ns
-delay = 20	inter = 19 s	inter = 9275 s 675716388 ns
-delay = 25	inter = 24 s	inter = 9300 s 679152476 ns
+delay = 0	inter = 0 s	time = 12023.773065613 s
+delay = 5	inter = 4 s	time = 12028.779487398 s
+delay = 10	inter = 9 s	time = 12038.887123080 s
+delay = 15	inter = 14 s	time = 12053.994505999 s
+delay = 20	inter = 19 s	time = 12073.001877621 s
+delay = 25	inter = 24 s	time = 12098.007975765 s
 sudo rmmod timer.ko
 lsmod | head -n 3
 Module                  Size  Used by

timer/timer.c

@@ -7,6 +7,8 @@
 #include <linux/ktime.h>
 
 #define TIMEOUT 1000U
+#define MAX_HR_BUFF 64
+#define DOT_POS 9
 
 static u32 inter_sec = 0;
 
@@ -16,7 +18,6 @@ static ssize_t time_show(struct class *class, struct class_attribute *attr,
 			 char *buffer);
 
 void inter_callback(struct timer_list *timer);
-//enum hrtimer_restart hr_callback(struct hrtimer *timer);
 
 static struct class *class_timer = NULL;
 CLASS_ATTR_RO(inter);
@@ -37,13 +38,19 @@ static ssize_t inter_show(struct class *class, struct class_attribute *attr,
 static ssize_t time_show(struct class *class, struct class_attribute *attr,
 			 char *buffer)
 {
-	static ktime_t time = 0;
-	static s32 hr_sec = 0;
-	static s64 hr_nsec = 0;
+	ktime_t time = 0;
+	char hr_sec[MAX_HR_BUFF] = "";
+	size_t len = 0;
 	time = hrtimer_cb_get_time(&hr_timer);
-	hr_sec = time / NSEC_PER_SEC;
-	hr_nsec = time % NSEC_PER_SEC;
-	sprintf(buffer, "inter = %u s %lld ns\n", hr_sec, hr_nsec);
+	len = snprintf(hr_sec, MAX_HR_BUFF, "%lld", time);
+	if (len > DOT_POS && len < MAX_HR_BUFF - 1) {
+		size_t i;
+		for (i = len - 1; i > len - DOT_POS; --i) {
+			hr_sec[i + 1] = hr_sec[i];
+		}
+		hr_sec[len - DOT_POS] = '.';
+	}
+	sprintf(buffer, "time = %s s\n", hr_sec);
 	return strlen(buffer);
 }
 
@@ -53,16 +60,6 @@ void inter_callback(struct timer_list *timer)
 	++inter_sec;
 }
 
-//For restarting the timer after ~585 years
-/*
-enum hrtimer_restart hr_callback(struct hrtimer *timer)
-{
-	//--restart actions--
-	hrtimer_forward_now(timer,KTIME_MAX));
-    	return HRTIMER_RESTART;
-}
-*/
-
 static int timer_init(void)
 {
 	int ret;
@@ -77,19 +74,18 @@ static int timer_init(void)
 
 	ret = class_create_file(class_timer, &class_attr_inter);
 	if (ret) {
-		printk(KERN_ERR "timer: bad create attribute inter: %d\n", ret);
+		printk(KERN_ERR "timer: bad attribute inter create: %d\n", ret);
 		return ret;
 	}
 
 	ret = class_create_file(class_timer, &class_attr_time);
 	if (ret) {
-		printk(KERN_ERR "timer: bad create attribute time: %d\n", ret);
+		printk(KERN_ERR "timer: bad attribute time create: %d\n", ret);
 		return ret;
 	}
 
 	add_timer(&inter_timer);
 	hrtimer_init(&hr_timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
-	//hr_timer.function = &hr_callback;
 
 	mod_timer(&inter_timer, jiffies + msecs_to_jiffies(TIMEOUT));
 	hrtimer_start(&hr_timer, KTIME_MAX, HRTIMER_MODE_REL);

timer/timer_test.sh

@@ -3,7 +3,6 @@
 make format
 make
 make install
-cat /sys/class/timer/inter
 for (( del = 0; del < 30; del += 5)); do
         sleep $del
         iter=$(cat /sys/class/timer/inter)