diff options
| author | Len Brown <len.brown@intel.com> | 2013-02-10 01:38:39 -0500 |
|---|---|---|
| committer | Len Brown <len.brown@intel.com> | 2013-02-10 03:03:41 -0500 |
| commit | 69fb3676df3329a7142803bb3502fa59dc0db2e3 (patch) | |
| tree | e2cfa5a6513e07d01e6b1fe935f09be8300d7bde /Documentation | |
| parent | 6a377ddc4e4ede2eeb9cd46ada23bbe417704fc9 (diff) | |
x86 idle: remove mwait_idle() and "idle=mwait" cmdline param
mwait_idle() is a C1-only idle loop intended to be more efficient
than HLT, starting on Pentium-4 HT-enabled processors.
But mwait_idle() has been replaced by the more general
mwait_idle_with_hints(), which handles both C1 and deeper C-states.
ACPI processor_idle and intel_idle use only mwait_idle_with_hints(),
and no longer use mwait_idle().
Here we simplify the x86 native idle code by removing mwait_idle(),
and the "idle=mwait" bootparam used to invoke it.
Since Linux 3.0 there has been a boot-time warning when "idle=mwait"
was invoked saying it would be removed in 2012. This removal
was also noted in the (now removed:-) feature-removal-schedule.txt.
After this change, kernels configured with
(CONFIG_ACPI=n && CONFIG_INTEL_IDLE=n) when run on hardware
that supports MWAIT will simply use HLT. If MWAIT is desired
on those systems, cpuidle and the cpuidle drivers above
can be enabled.
Signed-off-by: Len Brown <len.brown@intel.com>
Cc: x86@kernel.org
Diffstat (limited to 'Documentation')
| -rw-r--r-- | Documentation/kernel-parameters.txt | 7 |
1 files changed, 1 insertions, 6 deletions
diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt index 363e348bff9b..3b0cd1e612da 100644 --- a/Documentation/kernel-parameters.txt +++ b/Documentation/kernel-parameters.txt @@ -1039,16 +1039,11 @@ bytes respectively. Such letter suffixes can also be entirely omitted. Claim all unknown PCI IDE storage controllers. idle= [X86] - Format: idle=poll, idle=mwait, idle=halt, idle=nomwait + Format: idle=poll, idle=halt, idle=nomwait Poll forces a polling idle loop that can slightly improve the performance of waking up a idle CPU, but will use a lot of power and make the system run hot. Not recommended. - idle=mwait: On systems which support MONITOR/MWAIT but - the kernel chose to not use it because it doesn't save - as much power as a normal idle loop, use the - MONITOR/MWAIT idle loop anyways. Performance should be - the same as idle=poll. idle=halt: Halt is forced to be used for CPU idle. In such case C2/C3 won't be used again. idle=nomwait: Disable mwait for CPU C-states |