2.3 Userspace
2.4 Ondemand
2.5 Conservative
-2.6 Interactive
3. The Governor Interface in the CPUfreq Core
speed. Load for frequency increase is still evaluated every
sampling rate.
-2.6 Interactive
----------------
-
-The CPUfreq governor "interactive" is designed for latency-sensitive,
-interactive workloads. This governor sets the CPU speed depending on
-usage, similar to "ondemand" and "conservative" governors, but with a
-different set of configurable behaviors.
-
-The tuneable values for this governor are:
-
-target_loads: CPU load values used to adjust speed to influence the
-current CPU load toward that value. In general, the lower the target
-load, the more often the governor will raise CPU speeds to bring load
-below the target. The format is a single target load, optionally
-followed by pairs of CPU speeds and CPU loads to target at or above
-those speeds. Colons can be used between the speeds and associated
-target loads for readability. For example:
-
- 85 1000000:90 1700000:99
-
-targets CPU load 85% below speed 1GHz, 90% at or above 1GHz, until
-1.7GHz and above, at which load 99% is targeted. If speeds are
-specified these must appear in ascending order. Higher target load
-values are typically specified for higher speeds, that is, target load
-values also usually appear in an ascending order. The default is
-target load 90% for all speeds.
-
-min_sample_time: The minimum amount of time to spend at the current
-frequency before ramping down. Default is 80000 uS.
-
-hispeed_freq: An intermediate "hi speed" at which to initially ramp
-when CPU load hits the value specified in go_hispeed_load. If load
-stays high for the amount of time specified in above_hispeed_delay,
-then speed may be bumped higher. Default is the maximum speed
-allowed by the policy at governor initialization time.
-
-go_hispeed_load: The CPU load at which to ramp to hispeed_freq.
-Default is 99%.
-
-above_hispeed_delay: When speed is at or above hispeed_freq, wait for
-this long before raising speed in response to continued high load.
-The format is a single delay value, optionally followed by pairs of
-CPU speeds and the delay to use at or above those speeds. Colons can
-be used between the speeds and associated delays for readability. For
-example:
-
- 80000 1300000:200000 1500000:40000
-
-uses delay 80000 uS until CPU speed 1.3 GHz, at which speed delay
-200000 uS is used until speed 1.5 GHz, at which speed (and above)
-delay 40000 uS is used. If speeds are specified these must appear in
-ascending order. Default is 20000 uS.
-
-timer_rate: Sample rate for reevaluating CPU load when the CPU is not
-idle. A deferrable timer is used, such that the CPU will not be woken
-from idle to service this timer until something else needs to run.
-(The maximum time to allow deferring this timer when not running at
-minimum speed is configurable via timer_slack.) Default is 20000 uS.
-
-timer_slack: Maximum additional time to defer handling the governor
-sampling timer beyond timer_rate when running at speeds above the
-minimum. For platforms that consume additional power at idle when
-CPUs are running at speeds greater than minimum, this places an upper
-bound on how long the timer will be deferred prior to re-evaluating
-load and dropping speed. For example, if timer_rate is 20000uS and
-timer_slack is 10000uS then timers will be deferred for up to 30msec
-when not at lowest speed. A value of -1 means defer timers
-indefinitely at all speeds. Default is 80000 uS.
-
-boost: If non-zero, immediately boost speed of all CPUs to at least
-hispeed_freq until zero is written to this attribute. If zero, allow
-CPU speeds to drop below hispeed_freq according to load as usual.
-Default is zero.
-
-boostpulse: On each write, immediately boost speed of all CPUs to
-hispeed_freq for at least the period of time specified by
-boostpulse_duration, after which speeds are allowed to drop below
-hispeed_freq according to load as usual.
-
-boostpulse_duration: Length of time to hold CPU speed at hispeed_freq
-on a write to boostpulse, before allowing speed to drop according to
-load as usual. Default is 80000 uS.
-
-
3. The Governor Interface in the CPUfreq Core
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projects / firefly-linux-kernel-4.4.55.git / blobdiff