[CPUFREQ] Remove slowdown from ondemand sampling path.

Remove slowdown from ondemand sampling path. This reduces the code path length in dbs_check_cpu() by half. slowdown was not used by ondemand by default. If there are any user level tools that were using this tunable, they may report error now. Signed-off-by: Alexey Starikovskiy <alexey.y.starikovskiy@intel.com> Signed-off-by: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com> Signed-off-by: Dave Jones <davej@redhat.com>

[CPUFREQ] Remove slowdown from ondemand sampling path.
Remove slowdown from ondemand sampling path. This reduces the code path length in dbs_check_cpu() by half. slowdown was not used by ondemand by default. If there are any user level tools that were using this tunable, they may report error now. Signed-off-by: Alexey Starikovskiy <alexey.y.starikovskiy@intel.com> Signed-off-by: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com> Signed-off-by: Dave Jones <davej@redhat.com>
Venkatesh Pallipadi · Dave Jones
1 parent 501b7c77de
Showing 2 changed files with 42 additions and 98 deletions Side-by-side Diff
drivers/cpufreq/cpufreq_ondemand.c
include/asm-generic/cputime.h
@@ -56,16 +56,14 @@
 #define MIN_SAMPLING_RATE			(def_sampling_rate / MIN_SAMPLING_RATE_RATIO)
 #define MAX_SAMPLING_RATE			(500 * def_sampling_rate)
 #define DEF_SAMPLING_RATE_LATENCY_MULTIPLIER	(1000)
-#define DEF_SAMPLING_DOWN_FACTOR		(1)
-#define MAX_SAMPLING_DOWN_FACTOR		(10)
 #define TRANSITION_LATENCY_LIMIT		(10 * 1000)
  
 static void do_dbs_timer(void *data);
  
 struct cpu_dbs_info_s {
+	cputime64_t prev_cpu_idle;
+	cputime64_t prev_cpu_wall;
 	struct cpufreq_policy *cur_policy;
-	unsigned int prev_cpu_idle_up;
-	unsigned int prev_cpu_idle_down;
 	unsigned int enable;
 };
 static DEFINE_PER_CPU(struct cpu_dbs_info_s, cpu_dbs_info);
  
  
  
@@ -87,24 +85,26 @@
  
 struct dbs_tuners {
 	unsigned int sampling_rate;
-	unsigned int sampling_down_factor;
 	unsigned int up_threshold;
 	unsigned int ignore_nice;
 };
  
 static struct dbs_tuners dbs_tuners_ins = {
 	.up_threshold = DEF_FREQUENCY_UP_THRESHOLD,
-	.sampling_down_factor = DEF_SAMPLING_DOWN_FACTOR,
 	.ignore_nice = 0,
 };
  
-static inline unsigned int get_cpu_idle_time(unsigned int cpu)
+static inline cputime64_t get_cpu_idle_time(unsigned int cpu)
 {
-	return	kstat_cpu(cpu).cpustat.idle +
-		kstat_cpu(cpu).cpustat.iowait +
-		( dbs_tuners_ins.ignore_nice ?
-		  kstat_cpu(cpu).cpustat.nice :
-		  0);
+	cputime64_t retval;
+
+	retval = cputime64_add(kstat_cpu(cpu).cpustat.idle,
+			kstat_cpu(cpu).cpustat.iowait);
+
+	if (dbs_tuners_ins.ignore_nice)
+		retval = cputime64_add(retval, kstat_cpu(cpu).cpustat.nice);
+
+	return retval;
 }
  
 /************************** sysfs interface ************************/
  
@@ -133,29 +133,9 @@
 	return sprintf(buf, "%u\n", dbs_tuners_ins.object);		\
 }
 show_one(sampling_rate, sampling_rate);
-show_one(sampling_down_factor, sampling_down_factor);
 show_one(up_threshold, up_threshold);
 show_one(ignore_nice_load, ignore_nice);
  
-static ssize_t store_sampling_down_factor(struct cpufreq_policy *unused,
-		const char *buf, size_t count)
-{
-	unsigned int input;
-	int ret;
-	ret = sscanf (buf, "%u", &input);
-	if (ret != 1 )
-		return -EINVAL;
-
-	if (input > MAX_SAMPLING_DOWN_FACTOR || input < 1)
-		return -EINVAL;
-
-	mutex_lock(&dbs_mutex);
-	dbs_tuners_ins.sampling_down_factor = input;
-	mutex_unlock(&dbs_mutex);
-
-	return count;
-}
-
 static ssize_t store_sampling_rate(struct cpufreq_policy *unused,
 		const char *buf, size_t count)
 {
  
@@ -217,12 +197,12 @@
 	}
 	dbs_tuners_ins.ignore_nice = input;
  
-	/* we need to re-evaluate prev_cpu_idle_up and prev_cpu_idle_down */
+	/* we need to re-evaluate prev_cpu_idle */
 	for_each_online_cpu(j) {
-		struct cpu_dbs_info_s *j_dbs_info;
-		j_dbs_info = &per_cpu(cpu_dbs_info, j);
-		j_dbs_info->prev_cpu_idle_up = get_cpu_idle_time(j);
-		j_dbs_info->prev_cpu_idle_down = j_dbs_info->prev_cpu_idle_up;
+		struct cpu_dbs_info_s *dbs_info;
+		dbs_info = &per_cpu(cpu_dbs_info, j);
+		dbs_info->prev_cpu_idle = get_cpu_idle_time(j);
+		dbs_info->prev_cpu_wall = get_jiffies_64();
 	}
 	mutex_unlock(&dbs_mutex);
  
@@ -234,7 +214,6 @@
 __ATTR(_name, 0644, show_##_name, store_##_name)
  
 define_one_rw(sampling_rate);
-define_one_rw(sampling_down_factor);
 define_one_rw(up_threshold);
 define_one_rw(ignore_nice_load);
  
@@ -242,7 +221,6 @@
 	&sampling_rate_max.attr,
 	&sampling_rate_min.attr,
 	&sampling_rate.attr,
-	&sampling_down_factor.attr,
 	&up_threshold.attr,
 	&ignore_nice_load.attr,
 	NULL
  
@@ -257,11 +235,10 @@
  
 static void dbs_check_cpu(int cpu)
 {
-	unsigned int idle_ticks, up_idle_ticks, total_ticks;
-	unsigned int freq_next;
-	unsigned int freq_down_sampling_rate;
-	static int down_skip[NR_CPUS];
+	unsigned int idle_ticks, total_ticks;
+	unsigned int load;
 	struct cpu_dbs_info_s *this_dbs_info;
+	cputime64_t cur_jiffies;
  
 	struct cpufreq_policy *policy;
 	unsigned int j;
  
@@ -271,10 +248,14 @@
 		return;
  
 	policy = this_dbs_info->cur_policy;
+	cur_jiffies = jiffies64_to_cputime64(get_jiffies_64());
+	total_ticks = (unsigned int) cputime64_sub(cur_jiffies,
+			this_dbs_info->prev_cpu_wall);
+	this_dbs_info->prev_cpu_wall = cur_jiffies;
 	/*
 	 * Every sampling_rate, we check, if current idle time is less
 	 * than 20% (default), then we try to increase frequency
-	 * Every sampling_rate*sampling_down_factor, we look for a the lowest
+	 * Every sampling_rate, we look for a the lowest
 	 * frequency which can sustain the load while keeping idle time over
 	 * 30%. If such a frequency exist, we try to decrease to this frequency.
 	 *
  
  
  
  
@@ -283,36 +264,26 @@
 	 * 5% (default) of current frequency
 	 */
  
-	/* Check for frequency increase */
+	/* Get Idle Time */
 	idle_ticks = UINT_MAX;
 	for_each_cpu_mask(j, policy->cpus) {
-		unsigned int tmp_idle_ticks, total_idle_ticks;
+		cputime64_t total_idle_ticks;
+		unsigned int tmp_idle_ticks;
 		struct cpu_dbs_info_s *j_dbs_info;
  
 		j_dbs_info = &per_cpu(cpu_dbs_info, j);
 		total_idle_ticks = get_cpu_idle_time(j);
-		tmp_idle_ticks = total_idle_ticks -
-			j_dbs_info->prev_cpu_idle_up;
-		j_dbs_info->prev_cpu_idle_up = total_idle_ticks;
+		tmp_idle_ticks = (unsigned int) cputime64_sub(total_idle_ticks,
+				j_dbs_info->prev_cpu_idle);
+		j_dbs_info->prev_cpu_idle = total_idle_ticks;
  
 		if (tmp_idle_ticks < idle_ticks)
 			idle_ticks = tmp_idle_ticks;
 	}
+	load = (100 * (total_ticks - idle_ticks)) / total_ticks;
  
-	/* Scale idle ticks by 100 and compare with up and down ticks */
-	idle_ticks *= 100;
-	up_idle_ticks = (100 - dbs_tuners_ins.up_threshold) *
-			usecs_to_jiffies(dbs_tuners_ins.sampling_rate);
-
-	if (idle_ticks < up_idle_ticks) {
-		down_skip[cpu] = 0;
-		for_each_cpu_mask(j, policy->cpus) {
-			struct cpu_dbs_info_s *j_dbs_info;
-
-			j_dbs_info = &per_cpu(cpu_dbs_info, j);
-			j_dbs_info->prev_cpu_idle_down =
-					j_dbs_info->prev_cpu_idle_up;
-		}
+	/* Check for frequency increase */
+	if (load > dbs_tuners_ins.up_threshold) {
 		/* if we are already at full speed then break out early */
 		if (policy->cur == policy->max)
 			return;
  
  
  
  
@@ -323,50 +294,22 @@
 	}
  
 	/* Check for frequency decrease */
-	down_skip[cpu]++;
-	if (down_skip[cpu] < dbs_tuners_ins.sampling_down_factor)
-		return;
-
-	idle_ticks = UINT_MAX;
-	for_each_cpu_mask(j, policy->cpus) {
-		unsigned int tmp_idle_ticks, total_idle_ticks;
-		struct cpu_dbs_info_s *j_dbs_info;
-
-		j_dbs_info = &per_cpu(cpu_dbs_info, j);
-		/* Check for frequency decrease */
-		total_idle_ticks = j_dbs_info->prev_cpu_idle_up;
-		tmp_idle_ticks = total_idle_ticks -
-			j_dbs_info->prev_cpu_idle_down;
-		j_dbs_info->prev_cpu_idle_down = total_idle_ticks;
-
-		if (tmp_idle_ticks < idle_ticks)
-			idle_ticks = tmp_idle_ticks;
-	}
-
-	down_skip[cpu] = 0;
 	/* if we cannot reduce the frequency anymore, break out early */
 	if (policy->cur == policy->min)
 		return;
  
-	/* Compute how many ticks there are between two measurements */
-	freq_down_sampling_rate = dbs_tuners_ins.sampling_rate *
-		dbs_tuners_ins.sampling_down_factor;
-	total_ticks = usecs_to_jiffies(freq_down_sampling_rate);
-
 	/*
 	 * The optimal frequency is the frequency that is the lowest that
 	 * can support the current CPU usage without triggering the up
 	 * policy. To be safe, we focus 10 points under the threshold.
 	 */
-	freq_next = ((total_ticks - idle_ticks) * 100) / total_ticks;
-	freq_next = (freq_next * policy->cur) /
+	if (load < (dbs_tuners_ins.up_threshold - 10)) {
+		unsigned int freq_next;
+		freq_next = (policy->cur * load) /
 			(dbs_tuners_ins.up_threshold - 10);
  
-	if (freq_next < policy->min)
-		freq_next = policy->min;
-
-	if (freq_next <= ((policy->cur * 95) / 100))
 		__cpufreq_driver_target(policy, freq_next, CPUFREQ_RELATION_L);
+	}
 }
  
 static void do_dbs_timer(void *data)
@@ -432,9 +375,8 @@
 			j_dbs_info = &per_cpu(cpu_dbs_info, j);
 			j_dbs_info->cur_policy = policy;
  
-			j_dbs_info->prev_cpu_idle_up = get_cpu_idle_time(j);
-			j_dbs_info->prev_cpu_idle_down
-				= j_dbs_info->prev_cpu_idle_up;
+			j_dbs_info->prev_cpu_idle = get_cpu_idle_time(j);
+			j_dbs_info->prev_cpu_wall = get_jiffies_64();
 		}
 		this_dbs_info->enable = 1;
 		sysfs_create_group(&policy->kobj, &dbs_attr_group);
@@ -24,7 +24,9 @@
  
 #define cputime64_zero (0ULL)
 #define cputime64_add(__a, __b)		((__a) + (__b))
+#define cputime64_sub(__a, __b)		((__a) - (__b))
 #define cputime64_to_jiffies64(__ct)	(__ct)
+#define jiffies64_to_cputime64(__jif)	(__jif)
 #define cputime_to_cputime64(__ct)	((u64) __ct)
...	...	@@ -56,16 +56,14 @@
56	56	#define MIN_SAMPLING_RATE (def_sampling_rate / MIN_SAMPLING_RATE_RATIO)
57	57	#define MAX_SAMPLING_RATE (500 * def_sampling_rate)
58	58	#define DEF_SAMPLING_RATE_LATENCY_MULTIPLIER (1000)
59		-#define DEF_SAMPLING_DOWN_FACTOR (1)
60		-#define MAX_SAMPLING_DOWN_FACTOR (10)
61	59	#define TRANSITION_LATENCY_LIMIT (10 * 1000)
62	60
63	61	static void do_dbs_timer(void *data);
64	62
65	63	struct cpu_dbs_info_s {
	64	+ cputime64_t prev_cpu_idle;
	65	+ cputime64_t prev_cpu_wall;
66	66	struct cpufreq_policy *cur_policy;
67		- unsigned int prev_cpu_idle_up;
68		- unsigned int prev_cpu_idle_down;
69	67	unsigned int enable;
70	68	};
71	69	static DEFINE_PER_CPU(struct cpu_dbs_info_s, cpu_dbs_info);
72	70
73	71
74	72
...	...	@@ -87,24 +85,26 @@
87	85
88	86	struct dbs_tuners {
89	87	unsigned int sampling_rate;
90		- unsigned int sampling_down_factor;
91	88	unsigned int up_threshold;
92	89	unsigned int ignore_nice;
93	90	};
94	91
95	92	static struct dbs_tuners dbs_tuners_ins = {
96	93	.up_threshold = DEF_FREQUENCY_UP_THRESHOLD,
97		- .sampling_down_factor = DEF_SAMPLING_DOWN_FACTOR,
98	94	.ignore_nice = 0,
99	95	};
100	96
101		-static inline unsigned int get_cpu_idle_time(unsigned int cpu)
	97	+static inline cputime64_t get_cpu_idle_time(unsigned int cpu)
102	98	{
103		- return kstat_cpu(cpu).cpustat.idle +
104		- kstat_cpu(cpu).cpustat.iowait +
105		- ( dbs_tuners_ins.ignore_nice ?
106		- kstat_cpu(cpu).cpustat.nice :
107		- 0);
	99	+ cputime64_t retval;
	100	+
	101	+ retval = cputime64_add(kstat_cpu(cpu).cpustat.idle,
	102	+ kstat_cpu(cpu).cpustat.iowait);
	103	+
	104	+ if (dbs_tuners_ins.ignore_nice)
	105	+ retval = cputime64_add(retval, kstat_cpu(cpu).cpustat.nice);
	106	+
	107	+ return retval;
108	108	}
109	109
110	110	/************************ sysfs interface **********************/
111	111
...	...	@@ -133,29 +133,9 @@
133	133	return sprintf(buf, "%u\n", dbs_tuners_ins.object); \
134	134	}
135	135	show_one(sampling_rate, sampling_rate);
136		-show_one(sampling_down_factor, sampling_down_factor);
137	136	show_one(up_threshold, up_threshold);
138	137	show_one(ignore_nice_load, ignore_nice);
139	138
140		-static ssize_t store_sampling_down_factor(struct cpufreq_policy *unused,
141		- const char *buf, size_t count)
142		-{
143		- unsigned int input;
144		- int ret;
145		- ret = sscanf (buf, "%u", &input);
146		- if (ret != 1 )
147		- return -EINVAL;
148		-
149		- if (input > MAX_SAMPLING_DOWN_FACTOR \|\| input < 1)
150		- return -EINVAL;
151		-
152		- mutex_lock(&dbs_mutex);
153		- dbs_tuners_ins.sampling_down_factor = input;
154		- mutex_unlock(&dbs_mutex);
155		-
156		- return count;
157		-}
158		-
159	139	static ssize_t store_sampling_rate(struct cpufreq_policy *unused,
160	140	const char *buf, size_t count)
161	141	{
162	142
...	...	@@ -217,12 +197,12 @@
217	197	}
218	198	dbs_tuners_ins.ignore_nice = input;
219	199
220		- /* we need to re-evaluate prev_cpu_idle_up and prev_cpu_idle_down */
	200	+ /* we need to re-evaluate prev_cpu_idle */
221	201	for_each_online_cpu(j) {
222		- struct cpu_dbs_info_s *j_dbs_info;
223		- j_dbs_info = &per_cpu(cpu_dbs_info, j);
224		- j_dbs_info->prev_cpu_idle_up = get_cpu_idle_time(j);
225		- j_dbs_info->prev_cpu_idle_down = j_dbs_info->prev_cpu_idle_up;
	202	+ struct cpu_dbs_info_s *dbs_info;
	203	+ dbs_info = &per_cpu(cpu_dbs_info, j);
	204	+ dbs_info->prev_cpu_idle = get_cpu_idle_time(j);
	205	+ dbs_info->prev_cpu_wall = get_jiffies_64();
226	206	}
227	207	mutex_unlock(&dbs_mutex);
228	208
...	...	@@ -234,7 +214,6 @@
234	214	__ATTR(_name, 0644, show_##_name, store_##_name)
235	215
236	216	define_one_rw(sampling_rate);
237		-define_one_rw(sampling_down_factor);
238	217	define_one_rw(up_threshold);
239	218	define_one_rw(ignore_nice_load);
240	219
...	...	@@ -242,7 +221,6 @@
242	221	&sampling_rate_max.attr,
243	222	&sampling_rate_min.attr,
244	223	&sampling_rate.attr,
245		- &sampling_down_factor.attr,
246	224	&up_threshold.attr,
247	225	&ignore_nice_load.attr,
248	226	NULL
249	227
...	...	@@ -257,11 +235,10 @@
257	235
258	236	static void dbs_check_cpu(int cpu)
259	237	{
260		- unsigned int idle_ticks, up_idle_ticks, total_ticks;
261		- unsigned int freq_next;
262		- unsigned int freq_down_sampling_rate;
263		- static int down_skip[NR_CPUS];
	238	+ unsigned int idle_ticks, total_ticks;
	239	+ unsigned int load;
264	240	struct cpu_dbs_info_s *this_dbs_info;
	241	+ cputime64_t cur_jiffies;
265	242
266	243	struct cpufreq_policy *policy;
267	244	unsigned int j;
268	245
...	...	@@ -271,10 +248,14 @@
271	248	return;
272	249
273	250	policy = this_dbs_info->cur_policy;
	251	+ cur_jiffies = jiffies64_to_cputime64(get_jiffies_64());
	252	+ total_ticks = (unsigned int) cputime64_sub(cur_jiffies,
	253	+ this_dbs_info->prev_cpu_wall);
	254	+ this_dbs_info->prev_cpu_wall = cur_jiffies;
274	255	/*
275	256	* Every sampling_rate, we check, if current idle time is less
276	257	* than 20% (default), then we try to increase frequency
277		- * Every sampling_rate*sampling_down_factor, we look for a the lowest
	258	+ * Every sampling_rate, we look for a the lowest
278	259	* frequency which can sustain the load while keeping idle time over
279	260	* 30%. If such a frequency exist, we try to decrease to this frequency.
280	261	*
281	262
282	263
283	264
284	265
...	...	@@ -283,36 +264,26 @@
283	264	* 5% (default) of current frequency
284	265	*/
285	266
286		- /* Check for frequency increase */
	267	+ /* Get Idle Time */
287	268	idle_ticks = UINT_MAX;
288	269	for_each_cpu_mask(j, policy->cpus) {
289		- unsigned int tmp_idle_ticks, total_idle_ticks;
	270	+ cputime64_t total_idle_ticks;
	271	+ unsigned int tmp_idle_ticks;
290	272	struct cpu_dbs_info_s *j_dbs_info;
291	273
292	274	j_dbs_info = &per_cpu(cpu_dbs_info, j);
293	275	total_idle_ticks = get_cpu_idle_time(j);
294		- tmp_idle_ticks = total_idle_ticks -
295		- j_dbs_info->prev_cpu_idle_up;
296		- j_dbs_info->prev_cpu_idle_up = total_idle_ticks;
	276	+ tmp_idle_ticks = (unsigned int) cputime64_sub(total_idle_ticks,
	277	+ j_dbs_info->prev_cpu_idle);
	278	+ j_dbs_info->prev_cpu_idle = total_idle_ticks;
297	279
298	280	if (tmp_idle_ticks < idle_ticks)
299	281	idle_ticks = tmp_idle_ticks;
300	282	}
	283	+ load = (100 * (total_ticks - idle_ticks)) / total_ticks;
301	284
302		- /* Scale idle ticks by 100 and compare with up and down ticks */
303		- idle_ticks *= 100;
304		- up_idle_ticks = (100 - dbs_tuners_ins.up_threshold) *
305		- usecs_to_jiffies(dbs_tuners_ins.sampling_rate);
306		-
307		- if (idle_ticks < up_idle_ticks) {
308		- down_skip[cpu] = 0;
309		- for_each_cpu_mask(j, policy->cpus) {
310		- struct cpu_dbs_info_s *j_dbs_info;
311		-
312		- j_dbs_info = &per_cpu(cpu_dbs_info, j);
313		- j_dbs_info->prev_cpu_idle_down =
314		- j_dbs_info->prev_cpu_idle_up;
315		- }
	285	+ /* Check for frequency increase */
	286	+ if (load > dbs_tuners_ins.up_threshold) {
316	287	/* if we are already at full speed then break out early */
317	288	if (policy->cur == policy->max)
318	289	return;
319	290
320	291
321	292
322	293
...	...	@@ -323,50 +294,22 @@
323	294	}
324	295
325	296	/* Check for frequency decrease */
326		- down_skip[cpu]++;
327		- if (down_skip[cpu] < dbs_tuners_ins.sampling_down_factor)
328		- return;
329		-
330		- idle_ticks = UINT_MAX;
331		- for_each_cpu_mask(j, policy->cpus) {
332		- unsigned int tmp_idle_ticks, total_idle_ticks;
333		- struct cpu_dbs_info_s *j_dbs_info;
334		-
335		- j_dbs_info = &per_cpu(cpu_dbs_info, j);
336		- /* Check for frequency decrease */
337		- total_idle_ticks = j_dbs_info->prev_cpu_idle_up;
338		- tmp_idle_ticks = total_idle_ticks -
339		- j_dbs_info->prev_cpu_idle_down;
340		- j_dbs_info->prev_cpu_idle_down = total_idle_ticks;
341		-
342		- if (tmp_idle_ticks < idle_ticks)
343		- idle_ticks = tmp_idle_ticks;
344		- }
345		-
346		- down_skip[cpu] = 0;
347	297	/* if we cannot reduce the frequency anymore, break out early */
348	298	if (policy->cur == policy->min)
349	299	return;
350	300
351		- /* Compute how many ticks there are between two measurements */
352		- freq_down_sampling_rate = dbs_tuners_ins.sampling_rate *
353		- dbs_tuners_ins.sampling_down_factor;
354		- total_ticks = usecs_to_jiffies(freq_down_sampling_rate);
355		-
356	301	/*
357	302	* The optimal frequency is the frequency that is the lowest that
358	303	* can support the current CPU usage without triggering the up
359	304	* policy. To be safe, we focus 10 points under the threshold.
360	305	*/
361		- freq_next = ((total_ticks - idle_ticks) * 100) / total_ticks;
362		- freq_next = (freq_next * policy->cur) /
	306	+ if (load < (dbs_tuners_ins.up_threshold - 10)) {
	307	+ unsigned int freq_next;
	308	+ freq_next = (policy->cur * load) /
363	309	(dbs_tuners_ins.up_threshold - 10);
364	310
365		- if (freq_next < policy->min)
366		- freq_next = policy->min;
367		-
368		- if (freq_next <= ((policy->cur * 95) / 100))
369	311	__cpufreq_driver_target(policy, freq_next, CPUFREQ_RELATION_L);
	312	+ }
370	313	}
371	314
372	315	static void do_dbs_timer(void *data)
...	...	@@ -432,9 +375,8 @@
432	375	j_dbs_info = &per_cpu(cpu_dbs_info, j);
433	376	j_dbs_info->cur_policy = policy;
434	377
435		- j_dbs_info->prev_cpu_idle_up = get_cpu_idle_time(j);
436		- j_dbs_info->prev_cpu_idle_down
437		- = j_dbs_info->prev_cpu_idle_up;
	378	+ j_dbs_info->prev_cpu_idle = get_cpu_idle_time(j);
	379	+ j_dbs_info->prev_cpu_wall = get_jiffies_64();
438	380	}
439	381	this_dbs_info->enable = 1;
440	382	sysfs_create_group(&policy->kobj, &dbs_attr_group);
...	...	@@ -24,7 +24,9 @@
24	24
25	25	#define cputime64_zero (0ULL)
26	26	#define cputime64_add(__a, __b) ((__a) + (__b))
	27	+#define cputime64_sub(__a, __b) ((__a) - (__b))
27	28	#define cputime64_to_jiffies64(__ct) (__ct)
	29	+#define jiffies64_to_cputime64(__jif) (__jif)
28	30	#define cputime_to_cputime64(__ct) ((u64) __ct)
29	31
30	32