Yazen Ghannam
d4794f25f1
tools/power turbostat: Make interval calculation per thread to reduce jitter
Turbostat currently normalizes TSC and other values by dividing by an interval. This interval is the delta between the start of one global (all counters on all CPUs) sampling and the start of another. However, this introduces a lot of jitter into the data. In order to reduce jitter, the interval calculation should be based on timestamps taken per thread and close to the start of the thread's sampling. Define a per thread time value to hold the delta between samples taken on the thread. Use the timestamp taken at the beginning of sampling to calculate the delta. Move the thread's beginning timestamp to after the CPU migration to avoid jitter due to the migration. Use the global time delta for the average time delta. Signed-off-by: Yazen Ghannam <yazen.ghannam@amd.com> Signed-off-by: Len Brown <len.brown@intel.com>
Linux kernel ============ There are several guides for kernel developers and users. These guides can be rendered in a number of formats, like HTML and PDF. Please read Documentation/admin-guide/README.rst first. In order to build the documentation, use ``make htmldocs`` or ``make pdfdocs``. The formatted documentation can also be read online at: https://www.kernel.org/doc/html/latest/ There are various text files in the Documentation/ subdirectory, several of them using the Restructured Text markup notation. 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.
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