cpufreq: docs: Reflect latency changes in docs

There were two changes related to transition latency recently.
Namely commit e13aa799c2a6 ("cpufreq: Change default transition delay
to 2ms") and
commit 37c6dccd6837 ("cpufreq: Remove LATENCY_MULTIPLIER").

Both changed the defaults / maximums so let the documentation
reflect that.

Signed-off-by: Christian Loehle <christian.loehle@arm.com>
Link: https://patch.msgid.link/46853b6e-bad5-4ace-9b23-ff157f234ae3@arm.com
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

diff --git a/Documentation/admin-guide/pm/cpufreq.rst b/Documentation/admin-guide/pm/cpufreq.rst
index fe1be4a..a21369e 100644 (file)
--- a/Documentation/admin-guide/pm/cpufreq.rst
+++ b/Documentation/admin-guide/pm/cpufreq.rst
@@ -425,8 +425,8 @@ This governor exposes only one tunable:
 
 ``rate_limit_us``
        Minimum time (in microseconds) that has to pass between two consecutive
-       runs of governor computations (default: 1000 times the scaling driver's
-       transition latency).
+       runs of governor computations (default: 1.5 times the scaling driver's
+       transition latency or the maximum 2ms).
 
        The purpose of this tunable is to reduce the scheduler context overhead
        of the governor which might be excessive without it.
@@ -474,17 +474,17 @@ This governor exposes the following tunables:
        This is how often the governor's worker routine should run, in
        microseconds.
 
-       Typically, it is set to values of the order of 10000 (10 ms).  Its
-       default value is equal to the value of ``cpuinfo_transition_latency``
-       for each policy this governor is attached to (but since the unit here
-       is greater by 1000, this means that the time represented by
-       ``sampling_rate`` is 1000 times greater than the transition latency by
-       default).
+       Typically, it is set to values of the order of 2000 (2 ms).  Its
+       default value is to add a 50% breathing room
+       to ``cpuinfo_transition_latency`` on each policy this governor is
+       attached to. The minimum is typically the length of two scheduler
+       ticks.
 
        If this tunable is per-policy, the following shell command sets the time
-       represented by it to be 750 times as high as the transition latency::
+       represented by it to be 1.5 times as high as the transition latency
+       (the default)::
 
-       # echo `$(($(cat cpuinfo_transition_latency) * 750 / 1000)) > ondemand/sampling_rate
+       # echo `$(($(cat cpuinfo_transition_latency) * 3 / 2)) > ondemand/sampling_rate
 
 ``up_threshold``
        If the estimated CPU load is above this value (in percent), the governor