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authorLinus Torvalds <torvalds@linux-foundation.org>2009-06-17 09:51:50 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2009-06-17 09:51:50 -0700
commitc30938d59e7468259855da91a885b19e8044b5f4 (patch)
tree15fa3b7c4696947d43702273291398a91232f644 /Documentation
parentaa2638a210ab0d7c6702cd54315365785fce326c (diff)
parent8e7c25971b1590776a90b249de3d859dd45e7414 (diff)
Merge branch 'fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/davej/cpufreq
* 'fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/davej/cpufreq: [CPUFREQ] cpumask: new cpumask operators for arch/x86/kernel/cpu/cpufreq/powernow-k8.c [CPUFREQ] cpumask: avoid playing with cpus_allowed in powernow-k8.c [CPUFREQ] cpumask: avoid cpumask games in arch/x86/kernel/cpu/cpufreq/speedstep-centrino.c [CPUFREQ] cpumask: avoid playing with cpus_allowed in speedstep-ich.c [CPUFREQ] powernow-k8: get drv data for correct CPU [CPUFREQ] powernow-k8: read P-state from HW [CPUFREQ] reduce scope of ACPI_PSS_BIOS_BUG_MSG[] [CPUFREQ] Clean up convoluted code in arch/x86/kernel/tsc.c:time_cpufreq_notifier() [CPUFREQ] minor correction to cpu-freq documentation [CPUFREQ] powernow-k8.c: mess cleanup [CPUFREQ] Only set sampling_rate_max deprecated, sampling_rate_min is useful [CPUFREQ] powernow-k8: Set transition latency to 1 if ACPI tables export 0 [CPUFREQ] ondemand: Uncouple minimal sampling rate from HZ in NO_HZ case
Diffstat (limited to 'Documentation')
-rw-r--r--Documentation/cpu-freq/cpu-drivers.txt2
-rw-r--r--Documentation/cpu-freq/governors.txt26
-rw-r--r--Documentation/cpu-freq/user-guide.txt1
3 files changed, 15 insertions, 14 deletions
diff --git a/Documentation/cpu-freq/cpu-drivers.txt b/Documentation/cpu-freq/cpu-drivers.txt
index 43c743903dd..75a58d14d3c 100644
--- a/Documentation/cpu-freq/cpu-drivers.txt
+++ b/Documentation/cpu-freq/cpu-drivers.txt
@@ -155,7 +155,7 @@ actual frequency must be determined using the following rules:
- if relation==CPUFREQ_REL_H, try to select a new_freq lower than or equal
target_freq. ("H for highest, but no higher than")
-Here again the frequency table helper might assist you - see section 3
+Here again the frequency table helper might assist you - see section 2
for details.
diff --git a/Documentation/cpu-freq/governors.txt b/Documentation/cpu-freq/governors.txt
index ce73f3eb5dd..aed082f49d0 100644
--- a/Documentation/cpu-freq/governors.txt
+++ b/Documentation/cpu-freq/governors.txt
@@ -119,10 +119,6 @@ want the kernel to look at the CPU usage and to make decisions on
what to do about the frequency. Typically this is set to values of
around '10000' or more. It's default value is (cmp. with users-guide.txt):
transition_latency * 1000
-The lowest value you can set is:
-transition_latency * 100 or it may get restricted to a value where it
-makes not sense for the kernel anymore to poll that often which depends
-on your HZ config variable (HZ=1000: max=20000us, HZ=250: max=5000).
Be aware that transition latency is in ns and sampling_rate is in us, so you
get the same sysfs value by default.
Sampling rate should always get adjusted considering the transition latency
@@ -131,14 +127,20 @@ in the bash (as said, 1000 is default), do:
echo `$(($(cat cpuinfo_transition_latency) * 750 / 1000)) \
>ondemand/sampling_rate
-show_sampling_rate_(min|max): THIS INTERFACE IS DEPRECATED, DON'T USE IT.
-You can use wider ranges now and the general
-cpuinfo_transition_latency variable (cmp. with user-guide.txt) can be
-used to obtain exactly the same info:
-show_sampling_rate_min = transtition_latency * 500 / 1000
-show_sampling_rate_max = transtition_latency * 500000 / 1000
-(divided by 1000 is to illustrate that sampling rate is in us and
-transition latency is exported ns).
+show_sampling_rate_min:
+The sampling rate is limited by the HW transition latency:
+transition_latency * 100
+Or by kernel restrictions:
+If CONFIG_NO_HZ is set, the limit is 10ms fixed.
+If CONFIG_NO_HZ is not set or no_hz=off boot parameter is used, the
+limits depend on the CONFIG_HZ option:
+HZ=1000: min=20000us (20ms)
+HZ=250: min=80000us (80ms)
+HZ=100: min=200000us (200ms)
+The highest value of kernel and HW latency restrictions is shown and
+used as the minimum sampling rate.
+
+show_sampling_rate_max: THIS INTERFACE IS DEPRECATED, DON'T USE IT.
up_threshold: defines what the average CPU usage between the samplings
of 'sampling_rate' needs to be for the kernel to make a decision on
diff --git a/Documentation/cpu-freq/user-guide.txt b/Documentation/cpu-freq/user-guide.txt
index 75f41193f3e..5d5f5fadd1c 100644
--- a/Documentation/cpu-freq/user-guide.txt
+++ b/Documentation/cpu-freq/user-guide.txt
@@ -31,7 +31,6 @@ Contents:
3. How to change the CPU cpufreq policy and/or speed
3.1 Preferred interface: sysfs
-3.2 Deprecated interfaces