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Add a sysfs knob to enable/disable C1 demotion for the following Intel platforms: Sapphire Rapids Xeon, Emerald Rapids Xeon, Granite Rapids Xeon, Sierra Forest Xeon, and Grand Ridge SoC. This sysfs file shows up as "/sys/devices/system/cpu/cpuidle/intel_c1_demotion". The C1 demotion feature involves the platform firmware demoting deep C-state requests from the OS (e.g., C6 requests) to C1. The idea is that firmware monitors CPU wake-up rate, and if it is higher than a platform-specific threshold, the firmware demotes deep C-state requests to C1. For example, Linux requests C6, but firmware noticed too many wake-ups per second, and it keeps the CPU in C1. When the CPU stays in C1 long enough, the platform promotes it back to C6. The default value for C1 demotion is whatever is configured by BIOS. Signed-off-by: Artem Bityutskiy <artem.bityutskiy@linux.intel.com> Link: https://patch.msgid.link/20250317135541.1471754-2-dedekind1@gmail.com Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> |
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| block | ||
| certs | ||
| crypto | ||
| Documentation | ||
| drivers | ||
| fs | ||
| include | ||
| init | ||
| io_uring | ||
| ipc | ||
| kernel | ||
| lib | ||
| LICENSES | ||
| mm | ||
| net | ||
| rust | ||
| samples | ||
| scripts | ||
| security | ||
| sound | ||
| tools | ||
| usr | ||
| virt | ||
| .clang-format | ||
| .clippy.toml | ||
| .cocciconfig | ||
| .editorconfig | ||
| .get_maintainer.ignore | ||
| .gitattributes | ||
| .gitignore | ||
| .mailmap | ||
| .rustfmt.toml | ||
| COPYING | ||
| CREDITS | ||
| Kbuild | ||
| Kconfig | ||
| MAINTAINERS | ||
| Makefile | ||
| README | ||
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 reStructuredText 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.