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| author | Stratos Karafotis <stratosk@semaphore.gr> | 2013-03-05 23:06:29 +0100 |
|---|---|---|
| committer | Rafael J. Wysocki <rafael.j.wysocki@intel.com> | 2013-04-01 01:11:35 +0200 |
| commit | 7af1c0568d33339318c6710381921a3a3d40eebb (patch) | |
| tree | 4ae1c0bf763b140695e8efa0174e8453f9986ca7 | |
| parent | cpufreq: governors: Calculate iowait time only when necessary (diff) | |
| download | linux-7af1c0568d33339318c6710381921a3a3d40eebb.tar.xz linux-7af1c0568d33339318c6710381921a3a3d40eebb.zip | |
cpufreq: conservative: Fix sampling_down_factor functionality
sampling_down_factor tunable is unused since commit
8e677ce83bf41ba9c74e5b6d9ee60b07d4e5ed93 (4 years ago).
This patch restores the original functionality and documents the
tunable.
Signed-off-by: Stratos Karafotis <stratosk@semaphore.gr>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
| -rw-r--r-- | Documentation/cpu-freq/governors.txt | 6 | ||||
| -rw-r--r-- | drivers/cpufreq/cpufreq_conservative.c | 11 |
2 files changed, 14 insertions, 3 deletions
diff --git a/Documentation/cpu-freq/governors.txt b/Documentation/cpu-freq/governors.txt index c7a2eb8450c2..4dfed30b7fda 100644 --- a/Documentation/cpu-freq/governors.txt +++ b/Documentation/cpu-freq/governors.txt @@ -191,6 +191,12 @@ governor but for the opposite direction. For example when set to its default value of '20' it means that if the CPU usage needs to be below 20% between samples to have the frequency decreased. +sampling_down_factor: similar functionality as in "ondemand" governor. +But in "conservative", it controls the rate at which the kernel makes +a decision on when to decrease the frequency while running in any +speed. Load for frequency increase is still evaluated every +sampling rate. + 3. The Governor Interface in the CPUfreq Core ============================================= diff --git a/drivers/cpufreq/cpufreq_conservative.c b/drivers/cpufreq/cpufreq_conservative.c index 52f76b19a883..d746d6abbca8 100644 --- a/drivers/cpufreq/cpufreq_conservative.c +++ b/drivers/cpufreq/cpufreq_conservative.c @@ -36,9 +36,9 @@ static DEFINE_PER_CPU(struct cs_cpu_dbs_info_s, cs_cpu_dbs_info); /* * 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 check, if current idle time is more than 80%, then - * we try to decrease frequency + * (default), then we try to increase frequency. Every sampling_rate * + * sampling_down_factor, we check, if current idle time is more than 80% + * (default), then we try to decrease frequency * * Any frequency increase takes it to the maximum frequency. Frequency reduction * happens at minimum steps of 5% (default) of maximum frequency @@ -81,6 +81,11 @@ static void cs_check_cpu(int cpu, unsigned int load) return; } + /* if sampling_down_factor is active break out early */ + if (++dbs_info->down_skip < cs_tuners->sampling_down_factor) + return; + dbs_info->down_skip = 0; + /* * The optimal frequency is the frequency that is the lowest that can * support the current CPU usage without triggering the up policy. To be |