Merge "cpufreq: interactive: default go_hispeed_load 99%, doc updates"
diff --git a/Documentation/cpu-freq/governors.txt b/Documentation/cpu-freq/governors.txt
index 712f24d..b4ae5e6 100644
--- a/Documentation/cpu-freq/governors.txt
+++ b/Documentation/cpu-freq/governors.txt
@@ -198,23 +198,8 @@
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. However,
-the governor is more aggressive about scaling the CPU speed up in
-response to CPU-intensive activity.
-
-Sampling the CPU load every X ms can lead to under-powering the CPU
-for X ms, leading to dropped frames, stuttering UI, etc. Instead of
-sampling the cpu at a specified rate, the interactive governor will
-check whether to scale the cpu frequency up soon after coming out of
-idle. When the cpu comes out of idle, a timer is configured to fire
-within 1-2 ticks. If the cpu is very busy between exiting idle and
-when the timer fires then we assume the cpu is underpowered and ramp
-to MAX speed.
-
-If the cpu was not sufficiently busy to immediately ramp to MAX speed,
-then governor evaluates the cpu load since the last speed adjustment,
-choosing the highest value between that longer-term load or the
-short-term load since idle exit to determine the cpu speed to ramp to.
+usage, similar to "ondemand" and "conservative" governors, but with a
+different set of configurable behaviors.
The tuneable values for this governor are:
@@ -236,36 +221,51 @@
target load 90% for all speeds.
min_sample_time: The minimum amount of time to spend at the current
-frequency before ramping down. This is to ensure that the governor has
-seen enough historic cpu load data to determine the appropriate
-workload. Default is 80000 uS.
+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 maximum speed.
+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 the intermediate "hi
-speed". Default is 85%.
+go_hispeed_load: The CPU load at which to ramp to hispeed_freq.
+Default is 99%.
-above_hispeed_delay: Once speed is set to hispeed_freq, wait for this
-long before bumping speed higher in response to continued high load.
+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 system is
-not idle. 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.
-input_boost: If non-zero, boost speed of all CPUs to hispeed_freq on
-touchscreen activity. Default is 0.
+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: Immediately boost speed of all CPUs to hispeed_freq for
-min_sample_time, after which speeds are allowed to drop below
+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
=============================================
diff --git a/drivers/cpufreq/cpufreq_interactive.c b/drivers/cpufreq/cpufreq_interactive.c
index 4dc7f04..7ad6c00 100644
--- a/drivers/cpufreq/cpufreq_interactive.c
+++ b/drivers/cpufreq/cpufreq_interactive.c
@@ -65,7 +65,7 @@
static unsigned int hispeed_freq;
/* Go to hi speed when CPU load at or above this value. */
-#define DEFAULT_GO_HISPEED_LOAD 85
+#define DEFAULT_GO_HISPEED_LOAD 99
static unsigned long go_hispeed_load;
/* Target load. Lower values result in higher CPU speeds. */