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When turbostat shows % of time in a CPU idle power state, it has always been showing information from underlying hardware residency counters. While this reflects what the hardware is doing, and is thus useful for understanding the hardware, it doesn't directly tell us what Linux requested -- which is useful for tuning Linux itself. Here we add columns to turbostat to show the Linux cpuidle sub-system statistics: /sys/devices/system/cpu/cpu*/cpuidle/state*/* The first group of columns are the "usage", which is the number of times software requested that C-state in the measurement interval. eg C1 below. The second group of columns are the "time", which is the percentage of the measurement interval time that software has requested the specified C-state. eg C1% below. These software counters can be compared to the underlying hardware residency counters (eg CPU%c1 CPU%c3 CPU%c6 CPU%c7) to compare what sofware requested to what the hardware delivered. These sysfs attributes are discovered when turbostat starts, rather than being "built in". So the --show and --hide parameters do not know about these dynamic column names. However "--show sysfs" and "--hide sysfs" act on the entire group of columns: turbostat --show sysfs ... cpu4: POLL: CPUIDLE CORE POLL IDLE cpu4: C1: MWAIT 0x00 cpu4: C1E: MWAIT 0x01 cpu4: C3: MWAIT 0x10 cpu4: C6: MWAIT 0x20 cpu4: C7s: MWAIT 0x32 ... C1 C1E C3 C6 C7s C1% C1E% C3% C6% C7s% 3 6 5 1 188 0.00 0.02 0.00 0.00 99.93 0 6 5 0 58 0.00 0.16 0.02 0.00 99.70 0 0 0 0 9 0.00 0.00 0.00 0.00 99.96 0 0 0 1 24 0.00 0.00 0.00 0.02 99.93 0 0 0 0 9 0.00 0.00 0.00 0.00 99.97 0 0 0 0 32 0.00 0.00 0.00 0.00 99.96 0 0 0 0 7 0.00 0.00 0.00 0.00 99.98 2 0 0 0 36 0.00 0.00 0.00 0.00 99.97 1 0 0 0 13 0.00 0.00 0.00 0.00 99.98 Signed-off-by: Len Brown <len.brown@intel.com>
Linux kernel ============ This file was moved to Documentation/admin-guide/README.rst Please notice that there are several guides for kernel developers and users. These guides can be rendered in a number of formats, like HTML and PDF. In order to build the documentation, use ``make htmldocs`` or ``make pdfdocs``. There are various text files in the Documentation/ subdirectory, several of them using the Restructured Text markup notation. See Documentation/00-INDEX for a list of what is contained in each file. Please read the Documentation/process/changes.rst file, as it contains the requirements for building and running the kernel, and information about the problems which may result by upgrading your kernel.