Messages in this thread Patch in this message | | | Date | Fri, 24 Feb 2006 14:17:58 +0000 | From | Alexander Clouter <> | Subject | [patch 1/2] cpufreq_conservative: align codebase with ondemand for consistancy |
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Something I had been meaning to do for a while. The codebases between ondemand and conservative have strayed and as Venkatesh has far more Clue(tm) than I am going to adjust my code to look more like his :)
Another reason to do this is ages ago, knowingly, I did a piss poor attempt at making conservative less responsive by knocking up DEF_SAMPLING_RATE_LATENCY_MULTIPLIER by two orders of magnitude. I did fix this ages ago but in my dis-organisation I must have toasted the diff and left it the way it was. About two weeks ago a user contacted me saying he was having problems with the conservative governor with his AMD Athlon XP-M 2800+ as /sys/devices/system/cpu/cpu0/cpufreq/conservative showed sampling_rate_min 9950000 sampling_rate_max 1360065408
Nine seconds to decide about changing the frequency....not too responsive :)
N.B. only one bug remains, well on my machine, if anyone can see the cause then let me know. On my IBM T40p the cpu frequency only drops when the mouse moves (bizarre interrupt issue?). *Very* strange never the less...
Not using PREEMPT or DYNTICKS...any suggestions would be welcomed, no one else has reported the problem though.
Signed-off-by: Alexander Clouter <alex-kernel@digriz.org.uk> --- linux-2.6.15/drivers/cpufreq/cpufreq_conservative.c.orig 2006-02-09 18:05:36.157782500 +0000 +++ linux-2.6.15/drivers/cpufreq/cpufreq_conservative.c 2006-02-09 19:03:35.871251000 +0000 @@ -35,12 +35,7 @@ */ #define DEF_FREQUENCY_UP_THRESHOLD (80) -#define MIN_FREQUENCY_UP_THRESHOLD (0) -#define MAX_FREQUENCY_UP_THRESHOLD (100) - #define DEF_FREQUENCY_DOWN_THRESHOLD (20) -#define MIN_FREQUENCY_DOWN_THRESHOLD (0) -#define MAX_FREQUENCY_DOWN_THRESHOLD (100) /* * The polling frequency of this governor depends on the capability of @@ -53,10 +48,14 @@ * All times here are in uS. */ static unsigned int def_sampling_rate; -#define MIN_SAMPLING_RATE (def_sampling_rate / 2) +#define MIN_SAMPLING_RATE_RATIO (2) +/* for correct statistics, we need at least 10 ticks between each measure */ +#define MIN_STAT_SAMPLING_RATE (MIN_SAMPLING_RATE_RATIO * jiffies_to_usecs(10)) +#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 (100000) -#define DEF_SAMPLING_DOWN_FACTOR (5) +#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); @@ -139,6 +138,9 @@ if (ret != 1 ) return -EINVAL; + if (input > MAX_SAMPLING_DOWN_FACTOR || input < 1) + return -EINVAL; + down(&dbs_sem); dbs_tuners_ins.sampling_down_factor = input; up(&dbs_sem); @@ -173,8 +175,7 @@ ret = sscanf (buf, "%u", &input); down(&dbs_sem); - if (ret != 1 || input > MAX_FREQUENCY_UP_THRESHOLD || - input < MIN_FREQUENCY_UP_THRESHOLD || + if (ret != 1 || input > 100 || input < 0 || input <= dbs_tuners_ins.down_threshold) { up(&dbs_sem); return -EINVAL; @@ -194,8 +195,7 @@ ret = sscanf (buf, "%u", &input); down(&dbs_sem); - if (ret != 1 || input > MAX_FREQUENCY_DOWN_THRESHOLD || - input < MIN_FREQUENCY_DOWN_THRESHOLD || + if (ret != 1 || input > 100 || input < 0 || input >= dbs_tuners_ins.up_threshold) { up(&dbs_sem); return -EINVAL; @@ -280,8 +280,8 @@ &sampling_rate_min.attr, &sampling_rate.attr, &sampling_down_factor.attr, - &up_threshold.attr, &down_threshold.attr, + &up_threshold.attr, &ignore_nice.attr, &freq_step.attr, NULL @@ -337,7 +337,6 @@ */ /* Check for frequency increase */ - idle_ticks = UINT_MAX; for_each_cpu_mask(j, policy->cpus) { unsigned int tmp_idle_ticks, total_idle_ticks; @@ -357,7 +356,7 @@ /* 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); + usecs_to_jiffies(dbs_tuners_ins.sampling_rate); if (idle_ticks < up_idle_ticks) { down_skip[cpu] = 0; @@ -398,6 +397,7 @@ 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; @@ -414,12 +414,14 @@ freq_down_sampling_rate = dbs_tuners_ins.sampling_rate * dbs_tuners_ins.sampling_down_factor; down_idle_ticks = (100 - dbs_tuners_ins.down_threshold) * - usecs_to_jiffies(freq_down_sampling_rate); + 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 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 */ + * freq_step to be zero + */ if (requested_freq[cpu] == policy->min || dbs_tuners_ins.freq_step == 0) return; @@ -434,9 +436,8 @@ if (requested_freq[cpu] < policy->min) requested_freq[cpu] = policy->min; - __cpufreq_driver_target(policy, - requested_freq[cpu], - CPUFREQ_RELATION_H); + __cpufreq_driver_target(policy, requested_freq[cpu], + CPUFREQ_RELATION_H); return; } } @@ -507,13 +508,16 @@ if (dbs_enable == 1) { unsigned int latency; /* policy latency is in nS. Convert it to uS first */ + latency = policy->cpuinfo.transition_latency / 1000; + if (latency == 0) + latency = 1; - latency = policy->cpuinfo.transition_latency; - if (latency < 1000) - latency = 1000; - - def_sampling_rate = (latency / 1000) * + def_sampling_rate = latency * DEF_SAMPLING_RATE_LATENCY_MULTIPLIER; + + if (def_sampling_rate < MIN_STAT_SAMPLING_RATE) + def_sampling_rate = MIN_STAT_SAMPLING_RATE; + dbs_tuners_ins.sampling_rate = def_sampling_rate; dbs_tuners_ins.ignore_nice = 0; dbs_tuners_ins.freq_step = 5; | |