From 9ca8dbcc65cfc63d6f5ef3312a33184e1d726e00 Mon Sep 17 00:00:00 2001 From: Yunhong Jiang Date: Tue, 4 Aug 2015 12:17:53 -0700 Subject: Add the rt linux 4.1.3-rt3 as base Import the rt linux 4.1.3-rt3 as OPNFV kvm base. It's from git://git.kernel.org/pub/scm/linux/kernel/git/rt/linux-rt-devel.git linux-4.1.y-rt and the base is: commit 0917f823c59692d751951bf5ea699a2d1e2f26a2 Author: Sebastian Andrzej Siewior Date: Sat Jul 25 12:13:34 2015 +0200 Prepare v4.1.3-rt3 Signed-off-by: Sebastian Andrzej Siewior We lose all the git history this way and it's not good. We should apply another opnfv project repo in future. Change-Id: I87543d81c9df70d99c5001fbdf646b202c19f423 Signed-off-by: Yunhong Jiang --- kernel/Documentation/cpu-freq/cpufreq-stats.txt | 128 ++++++++++++++++++++++++ 1 file changed, 128 insertions(+) create mode 100644 kernel/Documentation/cpu-freq/cpufreq-stats.txt (limited to 'kernel/Documentation/cpu-freq/cpufreq-stats.txt') diff --git a/kernel/Documentation/cpu-freq/cpufreq-stats.txt b/kernel/Documentation/cpu-freq/cpufreq-stats.txt new file mode 100644 index 000000000..fc647492e --- /dev/null +++ b/kernel/Documentation/cpu-freq/cpufreq-stats.txt @@ -0,0 +1,128 @@ + + CPU frequency and voltage scaling statistics in the Linux(TM) kernel + + + L i n u x c p u f r e q - s t a t s d r i v e r + + - information for users - + + + Venkatesh Pallipadi + +Contents +1. Introduction +2. Statistics Provided (with example) +3. Configuring cpufreq-stats + + +1. Introduction + +cpufreq-stats is a driver that provides CPU frequency statistics for each CPU. +These statistics are provided in /sysfs as a bunch of read_only interfaces. This +interface (when configured) will appear in a separate directory under cpufreq +in /sysfs (/devices/system/cpu/cpuX/cpufreq/stats/) for each CPU. +Various statistics will form read_only files under this directory. + +This driver is designed to be independent of any particular cpufreq_driver +that may be running on your CPU. So, it will work with any cpufreq_driver. + + +2. Statistics Provided (with example) + +cpufreq stats provides following statistics (explained in detail below). +- time_in_state +- total_trans +- trans_table + +All the statistics will be from the time the stats driver has been inserted +to the time when a read of a particular statistic is done. Obviously, stats +driver will not have any information about the frequency transitions before +the stats driver insertion. + +-------------------------------------------------------------------------------- +:/sys/devices/system/cpu/cpu0/cpufreq/stats # ls -l +total 0 +drwxr-xr-x 2 root root 0 May 14 16:06 . +drwxr-xr-x 3 root root 0 May 14 15:58 .. +-r--r--r-- 1 root root 4096 May 14 16:06 time_in_state +-r--r--r-- 1 root root 4096 May 14 16:06 total_trans +-r--r--r-- 1 root root 4096 May 14 16:06 trans_table +-------------------------------------------------------------------------------- + +- time_in_state +This gives the amount of time spent in each of the frequencies supported by +this CPU. The cat output will have "