mainlining shenanigans
PCC regions utilize a mailbox to set/retrieve register values used by the CPPC code. This is fine as long as the operations are infrequent. With the FIE code enabled though the overhead can range from 2-11% of system CPU overhead (ex: as measured by top) on Arm based machines. So, before enabling FIE assure none of the registers used by cppc_get_perf_ctrs() are in the PCC region. Finally, add a module parameter which can override the PCC region detection at boot or module reload. Signed-off-by: Jeremy Linton <jeremy.linton@arm.com> Acked-by: Viresh Kumar <viresh.kumar@linaro.org> Reviewed-by: Ionela Voinescu <ionela.voinescu@arm.com> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> |
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arch | ||
block | ||
certs | ||
crypto | ||
Documentation | ||
drivers | ||
fs | ||
include | ||
init | ||
io_uring | ||
ipc | ||
kernel | ||
lib | ||
LICENSES | ||
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 |
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.