diff options
| 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 /arch/ia64/kernel/process.c | |
| parent | c1e3b377ad48febba6f91b8ae42c44ee4d4ab45e (diff) | |
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 'arch/ia64/kernel/process.c')
| -rw-r--r-- | arch/ia64/kernel/process.c | 2 |
1 files changed, 2 insertions, 0 deletions
diff --git a/arch/ia64/kernel/process.c b/arch/ia64/kernel/process.c index 612b3c4a0603..3ab8373103ec 100644 --- a/arch/ia64/kernel/process.c +++ b/arch/ia64/kernel/process.c @@ -57,6 +57,8 @@ unsigned long boot_option_idle_override = 0; EXPORT_SYMBOL(boot_option_idle_override); unsigned long idle_halt; EXPORT_SYMBOL(idle_halt); +unsigned long idle_nomwait; +EXPORT_SYMBOL(idle_nomwait); void ia64_do_show_stack (struct unw_frame_info *info, void *arg) |