From da5e09a1b3e5a9fc0b15a3feb64e921ccc55ba74 Mon Sep 17 00:00:00 2001 From: Zhao Yakui Date: Tue, 24 Jun 2008 18:01:09 +0800 Subject: 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 Signed-off-by: Li Shaohua Signed-off-by: Len Brown Signed-off-by: Andi Kleen --- Documentation/kernel-parameters.txt | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) (limited to 'Documentation') diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt index 65db7f4..5e497d1 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. -- cgit v1.1