cpufreq: Introduce new relation for freq selection

Introduce CPUFREQ_RELATION_C for frequency selection. It selects the frequency with the minimum euclidean distance to target. In case of equal distance between 2 frequencies, it will select the greater frequency. Signed-off-by: Stratos Karafotis <stratosk@semaphore.gr> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

cpufreq: Introduce new relation for freq selection
Introduce CPUFREQ_RELATION_C for frequency selection. It selects the frequency with the minimum euclidean distance to target. In case of equal distance between 2 frequencies, it will select the greater frequency. Signed-off-by: Stratos Karafotis <stratosk@semaphore.gr> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Stratos Karafotis · Rafael J. Wysocki
1 parent 22d0628a22
Showing 2 changed files with 12 additions and 1 deletions Side-by-side Diff
drivers/cpufreq/freq_table.c
include/linux/cpufreq.h
@@ -117,7 +117,7 @@
 		.frequency = 0,
 	};
 	struct cpufreq_frequency_table *pos;
-	unsigned int freq, i = 0;
+	unsigned int freq, diff, i = 0;
  
 	pr_debug("request for target %u kHz (relation: %u) for cpu %u\n",
 					target_freq, relation, policy->cpu);
@@ -127,6 +127,7 @@
 		suboptimal.frequency = ~0;
 		break;
 	case CPUFREQ_RELATION_L:
+	case CPUFREQ_RELATION_C:
 		optimal.frequency = ~0;
 		break;
 	}
@@ -166,6 +167,15 @@
 					suboptimal.frequency = freq;
 					suboptimal.driver_data = i;
 				}
+			}
+			break;
+		case CPUFREQ_RELATION_C:
+			diff = abs(freq - target_freq);
+			if (diff < optimal.frequency ||
+			    (diff == optimal.frequency &&
+			     freq > table[optimal.driver_data].frequency)) {
+				optimal.frequency = diff;
+				optimal.driver_data = i;
 			}
 			break;
 		}
@@ -176,6 +176,7 @@
  
 #define CPUFREQ_RELATION_L 0  /* lowest frequency at or above target */
 #define CPUFREQ_RELATION_H 1  /* highest frequency below or at target */
+#define CPUFREQ_RELATION_C 2  /* closest frequency to target */
  
 struct freq_attr {
 	struct attribute attr;
...	...	@@ -117,7 +117,7 @@
117	117	.frequency = 0,
118	118	};
119	119	struct cpufreq_frequency_table *pos;
120		- unsigned int freq, i = 0;
	120	+ unsigned int freq, diff, i = 0;
121	121
122	122	pr_debug("request for target %u kHz (relation: %u) for cpu %u\n",
123	123	target_freq, relation, policy->cpu);
...	...	@@ -127,6 +127,7 @@
127	127	suboptimal.frequency = ~0;
128	128	break;
129	129	case CPUFREQ_RELATION_L:
	130	+ case CPUFREQ_RELATION_C:
130	131	optimal.frequency = ~0;
131	132	break;
132	133	}
...	...	@@ -166,6 +167,15 @@
166	167	suboptimal.frequency = freq;
167	168	suboptimal.driver_data = i;
168	169	}
	170	+ }
	171	+ break;
	172	+ case CPUFREQ_RELATION_C:
	173	+ diff = abs(freq - target_freq);
	174	+ if (diff < optimal.frequency \|\|
	175	+ (diff == optimal.frequency &&
	176	+ freq > table[optimal.driver_data].frequency)) {
	177	+ optimal.frequency = diff;
	178	+ optimal.driver_data = i;
169	179	}
170	180	break;
171	181	}
...	...	@@ -176,6 +176,7 @@
176	176
177	177	#define CPUFREQ_RELATION_L 0 /* lowest frequency at or above target */
178	178	#define CPUFREQ_RELATION_H 1 /* highest frequency below or at target */
	179	+#define CPUFREQ_RELATION_C 2 /* closest frequency to target */
179	180
180	181	struct freq_attr {
181	182	struct attribute attr;