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| author | Linus Torvalds <torvalds@linux-foundation.org> | 2022-08-01 19:49:29 +0300 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2022-08-01 19:49:29 +0300 |
| commit | 42efa5e3a8888c45c15fc5a567cd77049a2e30f1 (patch) | |
| tree | b72f6bf5e213d60615b3e54fac9757127d0d665c /Documentation | |
| parent | 650ea1f626ab4d939fda00b7cca57698dcf57e5e (diff) | |
| parent | 3f2adf00f52b5f2e9e9f23bb5c77608fc9ee297c (diff) | |
| download | linux-42efa5e3a8888c45c15fc5a567cd77049a2e30f1.tar.xz | |
Merge tag 'x86_cpu_for_v6.0_rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull x86 cpu updates from Borislav Petkov:
- Remove the vendor check when selecting MWAIT as the default idle
state
- Respect idle=nomwait when supplied on the kernel cmdline
- Two small cleanups
* tag 'x86_cpu_for_v6.0_rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
x86/cpu: Use MSR_IA32_MISC_ENABLE constants
x86: Fix comment for X86_FEATURE_ZEN
x86: Remove vendor checks from prefer_mwait_c1_over_halt
x86: Handle idle=nomwait cmdline properly for x86_idle
Diffstat (limited to 'Documentation')
| -rw-r--r-- | Documentation/admin-guide/pm/cpuidle.rst | 15 |
1 files changed, 9 insertions, 6 deletions
diff --git a/Documentation/admin-guide/pm/cpuidle.rst b/Documentation/admin-guide/pm/cpuidle.rst index aec2cd2aaea7..19754beb5a4e 100644 --- a/Documentation/admin-guide/pm/cpuidle.rst +++ b/Documentation/admin-guide/pm/cpuidle.rst @@ -612,8 +612,8 @@ the ``menu`` governor to be used on the systems that use the ``ladder`` governor by default this way, for example. The other kernel command line parameters controlling CPU idle time management -described below are only relevant for the *x86* architecture and some of -them affect Intel processors only. +described below are only relevant for the *x86* architecture and references +to ``intel_idle`` affect Intel processors only. The *x86* architecture support code recognizes three kernel command line options related to CPU idle time management: ``idle=poll``, ``idle=halt``, @@ -635,10 +635,13 @@ idle, so it very well may hurt single-thread computations performance as well as energy-efficiency. Thus using it for performance reasons may not be a good idea at all.] -The ``idle=nomwait`` option disables the ``intel_idle`` driver and causes -``acpi_idle`` to be used (as long as all of the information needed by it is -there in the system's ACPI tables), but it is not allowed to use the -``MWAIT`` instruction of the CPUs to ask the hardware to enter idle states. +The ``idle=nomwait`` option prevents the use of ``MWAIT`` instruction of +the CPU to enter idle states. When this option is used, the ``acpi_idle`` +driver will use the ``HLT`` instruction instead of ``MWAIT``. On systems +running Intel processors, this option disables the ``intel_idle`` driver +and forces the use of the ``acpi_idle`` driver instead. Note that in either +case, ``acpi_idle`` driver will function only if all the information needed +by it is in the system's ACPI tables. In addition to the architecture-level kernel command line options affecting CPU idle time management, there are parameters affecting individual ``CPUIdle`` |