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When the hardware issues an HFI event, relay a notification to user space. This allows user space to respond by reading performance and efficiency of each CPU and take appropriate action. For example, when the performance and efficiency of a CPU is 0, user space can either offline the CPU or inject idle. Also, if user space notices a downward trend in performance, it may proactively adjust power limits to avoid future situations in which performance drops to 0. To avoid excessive notifications, the rate is limited by one HZ per event. To limit the netlink message size, send parameters for up to 16 CPUs in a single message. If there are more than 16 CPUs, issue as many messages as needed to notify the status of all CPUs. In the HFI specification, both performance and efficiency capabilities are defined in the [0, 255] range. The existing implementations of HFI hardware do not scale the maximum values to 255. Since userspace cares about capability values that are either 0 or show a downward/upward trend, this fact does not matter much. Relative changes in capabilities are enough. To comply with the thermal netlink ABI, scale both performance and efficiency capabilities to the [0, 1023] interval. Reviewed-by: Len Brown <len.brown@intel.com> Signed-off-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> |
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| Documentation | ||
| LICENSES | ||
| arch | ||
| block | ||
| certs | ||
| crypto | ||
| drivers | ||
| fs | ||
| include | ||
| init | ||
| ipc | ||
| kernel | ||
| lib | ||
| mm | ||
| net | ||
| samples | ||
| scripts | ||
| security | ||
| sound | ||
| tools | ||
| usr | ||
| virt | ||
| .clang-format | ||
| .cocciconfig | ||
| .get_maintainer.ignore | ||
| .gitattributes | ||
| .gitignore | ||
| .mailmap | ||
| COPYING | ||
| CREDITS | ||
| Kbuild | ||
| Kconfig | ||
| MAINTAINERS | ||
| Makefile | ||
| README | ||
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 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.