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| author | Zhao Yakui <yakui.zhao@intel.com> | 2008-06-24 18:01:09 +0800 |
|---|---|---|
| committer | Andi Kleen <andi@basil.nowhere.org> | 2008-07-16 23:27:05 +0200 |
| commit | da5e09a1b3e5a9fc0b15a3feb64e921ccc55ba74 (patch) | |
| tree | 382a75c1180e458df826ef4efbc191f3f71275c1 /Documentation/kernel-parameters.txt | |
| parent | c1e3b377ad48febba6f91b8ae42c44ee4d4ab45e (diff) | |
| download | lwn-da5e09a1b3e5a9fc0b15a3feb64e921ccc55ba74.tar.gz lwn-da5e09a1b3e5a9fc0b15a3feb64e921ccc55ba74.zip | |
ACPI : Create "idle=nomwait" bootparam
"idle=nomwait" disables the use of the MWAIT
instruction from both C1 (C1_FFH) and deeper (C2C3_FFH)
C-states.
When MWAIT is unavailable, the BIOS and OS generally
negotiate to use the HALT instruction for C1,
and use IO accesses for deeper C-states.
This option is useful for power and performance
comparisons, and also to work around BIOS bugs
where broken MWAIT support is advertised.
http://bugzilla.kernel.org/show_bug.cgi?id=10807
http://bugzilla.kernel.org/show_bug.cgi?id=10914
Signed-off-by: Zhao Yakui <yakui.zhao@intel.com>
Signed-off-by: Li Shaohua <shaohua.li@intel.com>
Signed-off-by: Len Brown <len.brown@intel.com>
Signed-off-by: Andi Kleen <ak@linux.intel.com>
Diffstat (limited to 'Documentation/kernel-parameters.txt')
| -rw-r--r-- | Documentation/kernel-parameters.txt | 3 |
1 files changed, 2 insertions, 1 deletions
diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt index 65db7f4711aa..5e497d16fb51 100644 --- a/Documentation/kernel-parameters.txt +++ b/Documentation/kernel-parameters.txt @@ -818,7 +818,7 @@ and is between 256 and 4096 characters. It is defined in the file See Documentation/ide/ide.txt. idle= [X86] - Format: idle=poll or idle=mwait, idle=halt + Format: idle=poll or idle=mwait, idle=halt, idle=nomwait Poll forces a polling idle loop that can slightly improves the performance of waking up a idle CPU, but will use a lot of power and make the system run hot. Not recommended. @@ -828,6 +828,7 @@ and is between 256 and 4096 characters. It is defined in the file 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 ide-pci-generic.all-generic-ide [HW] (E)IDE subsystem Claim all unknown PCI IDE storage controllers. |