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authorLinus Torvalds <torvalds@linux-foundation.org>2009-06-17 12:51:50 -0400
committerLinus Torvalds <torvalds@linux-foundation.org>2009-06-17 12:51:50 -0400
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 43c743903dd7..75a58d14d3cf 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:
155- if relation==CPUFREQ_REL_H, try to select a new_freq lower than or equal 155- if relation==CPUFREQ_REL_H, try to select a new_freq lower than or equal
156 target_freq. ("H for highest, but no higher than") 156 target_freq. ("H for highest, but no higher than")
157 157
158Here again the frequency table helper might assist you - see section 3 158Here again the frequency table helper might assist you - see section 2
159for details. 159for details.
160 160
161 161
diff --git a/Documentation/cpu-freq/governors.txt b/Documentation/cpu-freq/governors.txt
index ce73f3eb5ddb..aed082f49d09 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
119what to do about the frequency. Typically this is set to values of 119what to do about the frequency. Typically this is set to values of
120around '10000' or more. It's default value is (cmp. with users-guide.txt): 120around '10000' or more. It's default value is (cmp. with users-guide.txt):
121transition_latency * 1000 121transition_latency * 1000
122The lowest value you can set is:
123transition_latency * 100 or it may get restricted to a value where it
124makes not sense for the kernel anymore to poll that often which depends
125on your HZ config variable (HZ=1000: max=20000us, HZ=250: max=5000).
126Be aware that transition latency is in ns and sampling_rate is in us, so you 122Be aware that transition latency is in ns and sampling_rate is in us, so you
127get the same sysfs value by default. 123get the same sysfs value by default.
128Sampling rate should always get adjusted considering the transition latency 124Sampling rate should always get adjusted considering the transition latency
@@ -131,14 +127,20 @@ in the bash (as said, 1000 is default), do:
131echo `$(($(cat cpuinfo_transition_latency) * 750 / 1000)) \ 127echo `$(($(cat cpuinfo_transition_latency) * 750 / 1000)) \
132 >ondemand/sampling_rate 128 >ondemand/sampling_rate
133 129
134show_sampling_rate_(min|max): THIS INTERFACE IS DEPRECATED, DON'T USE IT. 130show_sampling_rate_min:
135You can use wider ranges now and the general 131The sampling rate is limited by the HW transition latency:
136cpuinfo_transition_latency variable (cmp. with user-guide.txt) can be 132transition_latency * 100
137used to obtain exactly the same info: 133Or by kernel restrictions:
138show_sampling_rate_min = transtition_latency * 500 / 1000 134If CONFIG_NO_HZ is set, the limit is 10ms fixed.
139show_sampling_rate_max = transtition_latency * 500000 / 1000 135If CONFIG_NO_HZ is not set or no_hz=off boot parameter is used, the
140(divided by 1000 is to illustrate that sampling rate is in us and 136limits depend on the CONFIG_HZ option:
141transition latency is exported ns). 137HZ=1000: min=20000us (20ms)
138HZ=250: min=80000us (80ms)
139HZ=100: min=200000us (200ms)
140The highest value of kernel and HW latency restrictions is shown and
141used as the minimum sampling rate.
142
143show_sampling_rate_max: THIS INTERFACE IS DEPRECATED, DON'T USE IT.
142 144
143up_threshold: defines what the average CPU usage between the samplings 145up_threshold: defines what the average CPU usage between the samplings
144of 'sampling_rate' needs to be for the kernel to make a decision on 146of '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 75f41193f3e1..5d5f5fadd1c2 100644
--- a/Documentation/cpu-freq/user-guide.txt
+++ b/Documentation/cpu-freq/user-guide.txt
@@ -31,7 +31,6 @@ Contents:
31 31
323. How to change the CPU cpufreq policy and/or speed 323. How to change the CPU cpufreq policy and/or speed
333.1 Preferred interface: sysfs 333.1 Preferred interface: sysfs
343.2 Deprecated interfaces
35 34
36 35
37 36