5969e0c1c7
struct perf_event_attr supports exclude counting of idle task. This is sent to kernel via perf_event_attr.exclude_idle and in perf tool, user can use ":I" event modifier to enable this for specific event. Monitor Mode Control Register 2 (MMCR2) SPR has control bits for each PMCs to freeze counting based on the Control Register CTRL[RUN] state. CTRL[RUN] is not set when idle task is running. Patch adds a check for event attr.exclude_idle to set MMCR2[FCnWAIT] bit. Signed-off-by: Madhavan Srinivasan <maddy@linux.ibm.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/20210429050208.266619-1-maddy@linux.ibm.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.