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Commit | Line | Data |
---|---|---|
2cb7cef9 BS |
1 | From: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com> |
2 | Subject: cpufreq,ondemand: Use get_cpu_idle_time_us() to get micro-accounted idle information | |
3 | ||
4 | Use get_cpu_idle_time_us() to get micro-accounted idle information. | |
5 | This enables ondemand to get more accurate idle and busy timings | |
6 | than the jiffy based calculation. As a result, we can decrease | |
7 | the ondemand safety gaurd band from 80-10 to 95-3. | |
8 | ||
9 | Results in more aggressive power savings. | |
10 | ||
11 | Signed-off-by: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com> | |
12 | Signed-off-by: Thomas Renninger <trenn@suse.de> | |
13 | ||
14 | --- | |
15 | drivers/cpufreq/cpufreq_ondemand.c | 46 ++++++++++++++++++++++++++++++++++++- | |
16 | 1 file changed, 45 insertions(+), 1 deletion(-) | |
17 | ||
18 | Index: cpufreq.git/drivers/cpufreq/cpufreq_ondemand.c | |
19 | =================================================================== | |
20 | --- cpufreq.git.orig/drivers/cpufreq/cpufreq_ondemand.c 2008-07-31 14:52:15.000000000 -0700 | |
21 | +++ cpufreq.git/drivers/cpufreq/cpufreq_ondemand.c 2008-07-31 14:52:22.000000000 -0700 | |
22 | @@ -18,6 +18,9 @@ | |
23 | #include <linux/jiffies.h> | |
24 | #include <linux/kernel_stat.h> | |
25 | #include <linux/mutex.h> | |
26 | +#include <linux/hrtimer.h> | |
27 | +#include <linux/tick.h> | |
28 | +#include <linux/ktime.h> | |
29 | ||
30 | /* | |
31 | * dbs is used in this file as a shortform for demandbased switching | |
32 | @@ -26,6 +29,8 @@ | |
33 | ||
34 | #define DEF_FREQUENCY_DOWN_DIFFERENTIAL (10) | |
35 | #define DEF_FREQUENCY_UP_THRESHOLD (80) | |
36 | +#define MICRO_FREQUENCY_DOWN_DIFFERENTIAL (3) | |
37 | +#define MICRO_FREQUENCY_UP_THRESHOLD (95) | |
38 | #define MIN_FREQUENCY_UP_THRESHOLD (11) | |
39 | #define MAX_FREQUENCY_UP_THRESHOLD (100) | |
40 | ||
41 | @@ -58,6 +63,7 @@ enum {DBS_NORMAL_SAMPLE, DBS_SUB_SAMPLE} | |
42 | struct cpu_dbs_info_s { | |
43 | cputime64_t prev_cpu_idle; | |
44 | cputime64_t prev_cpu_wall; | |
45 | + cputime64_t prev_cpu_nice; | |
46 | struct cpufreq_policy *cur_policy; | |
47 | struct delayed_work work; | |
48 | struct cpufreq_frequency_table *freq_table; | |
49 | @@ -97,7 +103,8 @@ static struct dbs_tuners { | |
50 | .powersave_bias = 0, | |
51 | }; | |
52 | ||
53 | -static inline cputime64_t get_cpu_idle_time(unsigned int cpu, cputime64_t *wall) | |
54 | +static inline cputime64_t get_cpu_idle_time_jiffy(unsigned int cpu, | |
55 | + cputime64_t *wall) | |
56 | { | |
57 | cputime64_t idle_time; | |
58 | cputime64_t cur_wall_time; | |
59 | @@ -123,6 +130,33 @@ static inline cputime64_t get_cpu_idle_t | |
60 | return idle_time; | |
61 | } | |
62 | ||
63 | +static inline cputime64_t get_cpu_idle_time(unsigned int cpu, cputime64_t *wall) | |
64 | +{ | |
65 | + u64 idle_time = get_cpu_idle_time_us(cpu, wall); | |
66 | + | |
67 | + if (idle_time == -1ULL) | |
68 | + return get_cpu_idle_time_jiffy(cpu, wall); | |
69 | + | |
70 | + if (dbs_tuners_ins.ignore_nice) { | |
71 | + cputime64_t cur_nice; | |
72 | + unsigned long cur_nice_jiffies; | |
73 | + struct cpu_dbs_info_s *dbs_info; | |
74 | + | |
75 | + dbs_info = &per_cpu(cpu_dbs_info, cpu); | |
76 | + cur_nice = cputime64_sub(kstat_cpu(cpu).cpustat.nice, | |
77 | + dbs_info->prev_cpu_nice); | |
78 | + /* | |
79 | + * Assumption: nice time between sampling periods will be | |
80 | + * less than 2^32 jiffies for 32 bit sys | |
81 | + */ | |
82 | + cur_nice_jiffies = (unsigned long) | |
83 | + cputime64_to_jiffies64(cur_nice); | |
84 | + dbs_info->prev_cpu_nice = kstat_cpu(cpu).cpustat.nice; | |
85 | + return idle_time + jiffies_to_usecs(cur_nice_jiffies); | |
86 | + } | |
87 | + return idle_time; | |
88 | +} | |
89 | + | |
90 | /* | |
91 | * Find right freq to be set now with powersave_bias on. | |
92 | * Returns the freq_hi to be used right now and will set freq_hi_jiffies, | |
93 | @@ -602,6 +636,16 @@ EXPORT_SYMBOL(cpufreq_gov_ondemand); | |
94 | ||
95 | static int __init cpufreq_gov_dbs_init(void) | |
96 | { | |
97 | + cputime64_t wall; | |
98 | + u64 idle_time = get_cpu_idle_time_us(smp_processor_id(), &wall); | |
99 | + | |
100 | + if (idle_time != -1ULL) { | |
101 | + /* Idle micro accounting is supported. Use finer thresholds */ | |
102 | + dbs_tuners_ins.up_threshold = MICRO_FREQUENCY_UP_THRESHOLD; | |
103 | + dbs_tuners_ins.down_differential = | |
104 | + MICRO_FREQUENCY_DOWN_DIFFERENTIAL; | |
105 | + } | |
106 | + | |
107 | kondemand_wq = create_workqueue("kondemand"); | |
108 | if (!kondemand_wq) { | |
109 | printk(KERN_ERR "Creation of kondemand failed\n"); | |
110 | ||
111 | -- |