X-Git-Url: http://demsky.eecs.uci.edu/git/?a=blobdiff_plain;f=Documentation%2Fcpu-freq%2Fgovernors.txt;h=4d8ae34f7bba117ad7f1cb436be9b60246d9170e;hb=b4f2820d791c456ba57ea2ab7848dae2f8135af4;hp=c15aa75f52275b703e3da46faff2a95e2ccfc6e9;hpb=f7c0af824711a88b47debbe295f17be6c0556539;p=firefly-linux-kernel-4.4.55.git

diff --git a/Documentation/cpu-freq/governors.txt b/Documentation/cpu-freq/governors.txt
index c15aa75f5227..4d8ae34f7bba 100644
--- a/Documentation/cpu-freq/governors.txt
+++ b/Documentation/cpu-freq/governors.txt
@@ -28,6 +28,7 @@ Contents:
 2.3  Userspace
 2.4  Ondemand
 2.5  Conservative
+2.6  Interactive
 
 3.   The Governor Interface in the CPUfreq Core
 
@@ -218,6 +219,80 @@ a decision on when to decrease the frequency while running in any
 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.
+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
 =============================================