[PATCH] (3/3) cpufreq_ondemand - 03_sys_freq_step.diff

[PATCH] (3/3) cpufreq_ondemand - 03_sys_freq_step.diff

[Alexander Clouter]

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Adds support so that the cpufreq change stepping is no longer fixed at 5% and 
can be changed dynamically by the user

Signed-off-by: Alexander Clouter <alex-kernel@digriz.org.uk>

-- 
 _________________________________________ 
/ It is wise to keep in mind that neither \
| success nor failure is ever final.      |
|                                         |
\ -- Roger Babson                         /
 ----------------------------------------- 
        \   ^__^
         \  (oo)\_______
            (__)\       )\/\
                ||----w |
                ||     ||

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--- linux-2.6.11-rc3-mm2.orig/drivers/cpufreq/cpufreq_ondemand.c	2005-02-20 11:36:56.082671840 +0000
+++ linux-2.6.11-rc3-mm2/drivers/cpufreq/cpufreq_ondemand.c	2005-02-20 11:37:13.371043608 +0000
@@ -80,6 +80,7 @@
 	unsigned int		up_threshold;
 	unsigned int		down_threshold;
 	unsigned int		ignore_nice;
+	unsigned int		freq_step;
 };
 
 static struct dbs_tuners dbs_tuners_ins = {
@@ -118,6 +119,7 @@
 show_one(up_threshold, up_threshold);
 show_one(down_threshold, down_threshold);
 show_one(ignore_nice, ignore_nice);
+show_one(freq_step, freq_step);
 
 static ssize_t store_sampling_down_factor(struct cpufreq_policy *unused, 
 		const char *buf, size_t count)
@@ -236,6 +238,29 @@
 	return count;
 }
 
+static ssize_t store_freq_step(struct cpufreq_policy *policy,
+		const char *buf, size_t count)
+{
+	unsigned int input;
+	int ret;
+
+	ret = sscanf (buf, "%u", &input);
+
+	if ( ret != 1 )
+		return -EINVAL;
+
+	if ( input > 100 )
+		input = 100;
+	
+	/* no need to test here if freq_step is zero as the user might actually
+	 * want this, they would be crazy though :) */
+	down(&dbs_sem);
+	dbs_tuners_ins.freq_step = input;
+	up(&dbs_sem);
+
+	return count;
+}
+
 #define define_one_rw(_name) \
 static struct freq_attr _name = \
 __ATTR(_name, 0644, show_##_name, store_##_name)
@@ -245,6 +270,7 @@
 define_one_rw(up_threshold);
 define_one_rw(down_threshold);
 define_one_rw(ignore_nice);
+define_one_rw(freq_step);
 
 static struct attribute * dbs_attributes[] = {
 	&sampling_rate_max.attr,
@@ -254,6 +280,7 @@
 	&up_threshold.attr,
 	&down_threshold.attr,
 	&ignore_nice.attr,
+	&freq_step.attr,
 	NULL
 };
 
@@ -292,7 +319,7 @@
 	 *
 	 * Any frequency increase takes it to the maximum frequency. 
 	 * Frequency reduction happens at minimum steps of 
-	 * 5% of max_frequency 
+	 * 5% (default) of max_frequency 
 	 */
 
 	/* Check for frequency increase */
@@ -391,18 +418,20 @@
 			sampling_rate_in_HZ(freq_down_sampling_rate);
 
 	if (idle_ticks > down_idle_ticks ) {
-		/* if we are already at the lowest speed then break out early */
-		if (policy->cur == policy->min)
+		/* if we are already at the lowest speed then break out early
+		 * or if we 'cannot' reduce the speed as the user might want
+		 * freq_step to be zero */
+		if (policy->cur == policy->min || dbs_tuners_ins.freq_step == 0)
 			return;
-		
-		freq_down_step = (5 * policy->max) / 100;
+
+		freq_down_step = (dbs_tuners_ins.freq_step * policy->max) / 100;
 
 		/* max freq cannot be less than 100. But who knows.... */
 		if (unlikely(freq_down_step == 0))
 			freq_down_step = 5;
 
 		__cpufreq_driver_target(policy,
-			policy->cur - freq_down_step, 
+			policy->cur - freq_down_step,
 			CPUFREQ_RELATION_H);
 		return;
 	}
@@ -488,6 +517,7 @@
 					DEF_SAMPLING_RATE_LATENCY_MULTIPLIER;
 			dbs_tuners_ins.sampling_rate = def_sampling_rate;
 			dbs_tuners_ins.ignore_nice = 0;
+			dbs_tuners_ins.freq_step = 5;
 
 			dbs_timer_init();
 		}

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Re: [PATCH] (3/3) cpufreq_ondemand - 03_sys_freq_step.diff

[Bruno Ducrot]

On Sun, Feb 20, 2005 at 01:18:08PM +0000, Alexander Clouter wrote:
> Adds support so that the cpufreq change stepping is no longer fixed at 5% and 
> can be changed dynamically by the user
> 

The cpufreq core will step to the next available frequency (in both
direction).  So I failed to see the usefullness for this one.

-- 
Bruno Ducrot

--  Which is worse:  ignorance or apathy?
--  Don't know.  Don't care.

Re: [PATCH] (3/3) cpufreq_ondemand - 03_sys_freq_step.diff

[Dominik Brodowski]

On Mon, Feb 21, 2005 at 04:17:50PM +0100, Bruno Ducrot wrote:
> On Sun, Feb 20, 2005 at 01:18:08PM +0000, Alexander Clouter wrote:
> > Adds support so that the cpufreq change stepping is no longer fixed at 5% and 
> > can be changed dynamically by the user
> > 
> 
> The cpufreq core will step to the next available frequency (in both
> direction).  So I failed to see the usefullness for this one.

If the load is going down, this tunable defines in what frequency steps the
"target" frequency is decreased -- _then_ the cpufreq core determines which
frequency close to the target is actually supported by the hardware.

Thanks,
	Dominik

[PATCH] (3/3) cpufreq_ondemand - 03_sys_freq_step.diff

[Alexander Clouter]

[-- Attachment #1.1.1: Type: text/plain, Size: 490 bytes --]

Adds support so that the cpufreq change stepping is no longer fixed at 5% and
can be changed dynamically by the user

Signed-off-by: Alexander Clouter <alex-kernel@digriz.org.uk>

-- 
 _______________________________________ 
/ It is a poor judge who cannot award a \
\ prize.                                /
 --------------------------------------- 
        \   ^__^
         \  (oo)\_______
            (__)\       )\/\
                ||----w |
                ||     ||

[-- Attachment #1.1.2: cpufreq_ondemand-2.6.12-rc3-mm3-03_sys_freq_step.diff --]
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--- linux-2.6.12-rc3-mm3.orig/drivers/cpufreq/cpufreq_ondemand.c	2005-05-10 22:23:51.692480816 +0100
+++ linux-2.6.12-rc3-mm3/drivers/cpufreq/cpufreq_ondemand.c	2005-05-10 22:24:10.032692680 +0100
@@ -79,6 +79,7 @@
 	unsigned int		up_threshold;
 	unsigned int		down_threshold;
 	unsigned int		ignore_nice;
+	unsigned int		freq_step;
 };
 
 static struct dbs_tuners dbs_tuners_ins = {
@@ -117,6 +118,7 @@
 show_one(up_threshold, up_threshold);
 show_one(down_threshold, down_threshold);
 show_one(ignore_nice, ignore_nice);
+show_one(freq_step, freq_step);
 
 static ssize_t store_sampling_down_factor(struct cpufreq_policy *unused, 
 		const char *buf, size_t count)
@@ -235,6 +237,29 @@
 	return count;
 }
 
+static ssize_t store_freq_step(struct cpufreq_policy *policy,
+		const char *buf, size_t count)
+{
+	unsigned int input;
+	int ret;
+
+	ret = sscanf (buf, "%u", &input);
+
+	if ( ret != 1 )
+		return -EINVAL;
+
+	if ( input > 100 )
+		input = 100;
+	
+	/* no need to test here if freq_step is zero as the user might actually
+	 * want this, they would be crazy though :) */
+	down(&dbs_sem);
+	dbs_tuners_ins.freq_step = input;
+	up(&dbs_sem);
+
+	return count;
+}
+
 #define define_one_rw(_name) \
 static struct freq_attr _name = \
 __ATTR(_name, 0644, show_##_name, store_##_name)
@@ -244,6 +269,7 @@
 define_one_rw(up_threshold);
 define_one_rw(down_threshold);
 define_one_rw(ignore_nice);
+define_one_rw(freq_step);
 
 static struct attribute * dbs_attributes[] = {
 	&sampling_rate_max.attr,
@@ -253,6 +279,7 @@
 	&up_threshold.attr,
 	&down_threshold.attr,
 	&ignore_nice.attr,
+	&freq_step.attr,
 	NULL
 };
 
@@ -291,7 +318,7 @@
 	 *
 	 * Any frequency increase takes it to the maximum frequency. 
 	 * Frequency reduction happens at minimum steps of 
-	 * 5% of max_frequency 
+	 * 5% (default) of max_frequency 
 	 */
 
 	/* Check for frequency increase */
@@ -390,18 +417,20 @@
 			usecs_to_jiffies(freq_down_sampling_rate);
 
 	if (idle_ticks > down_idle_ticks ) {
-		/* if we are already at the lowest speed then break out early */
-		if (policy->cur == policy->min)
+		/* if we are already at the lowest speed then break out early
+		 * or if we 'cannot' reduce the speed as the user might want
+		 * freq_step to be zero */
+		if (policy->cur == policy->min || dbs_tuners_ins.freq_step == 0)
 			return;
-		
-		freq_down_step = (5 * policy->max) / 100;
+
+		freq_down_step = (dbs_tuners_ins.freq_step * policy->max) / 100;
 
 		/* max freq cannot be less than 100. But who knows.... */
 		if (unlikely(freq_down_step == 0))
 			freq_down_step = 5;
 
 		__cpufreq_driver_target(policy,
-			policy->cur - freq_down_step, 
+			policy->cur - freq_down_step,
 			CPUFREQ_RELATION_H);
 		return;
 	}
@@ -486,6 +515,7 @@
 					DEF_SAMPLING_RATE_LATENCY_MULTIPLIER;
 			dbs_tuners_ins.sampling_rate = def_sampling_rate;
 			dbs_tuners_ins.ignore_nice = 0;
+			dbs_tuners_ins.freq_step = 5;
 
 			dbs_timer_init();
 		}

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