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| author | Ingo Molnar <mingo@elte.hu> | 2008-06-19 16:32:14 +0200 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@suse.de> | 2008-06-21 22:24:57 -0700 |
| commit | 384353364373c7c9f8134a847a35e27642cb6dae (patch) | |
| tree | d4191107a9bcd8a1d7288330673054272c3ace15 | |
| parent | b2e4b1cc4a1bfa05582949065a2c97ce7ab3caa3 (diff) | |
x86: remove mwait capability C-state check
back-ported from upstream commit a738d897b7b03b83488ae74a9bc03d26a2875dc6 by Vegard Nossum
Vegard Nossum reports:
| powertop shows between 200-400 wakeups/second with the description
| "<kernel IPI>: Rescheduling interrupts" when all processors have load (e.g.
| I need to run two busy-loops on my 2-CPU system for this to show up).
|
| The bisect resulted in this commit:
|
| commit 0c07ee38c9d4eb081758f5ad14bbffa7197e1aec
| Date: Wed Jan 30 13:33:16 2008 +0100
|
| x86: use the correct cpuid method to detect MWAIT support for C states
remove the functional effects of this patch and make mwait unconditional.
A future patch will turn off mwait on specific CPUs where that causes
power to be wasted.
Bisected-by: Vegard Nossum <vegard.nossum@gmail.com>
Tested-by: Vegard Nossum <vegard.nossum@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Vegard Nossum <vegard.nossum@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
| -rw-r--r-- | arch/x86/kernel/process_32.c | 10 | ||||
| -rw-r--r-- | arch/x86/kernel/process_64.c | 11 |
2 files changed, 2 insertions, 19 deletions
diff --git a/arch/x86/kernel/process_32.c b/arch/x86/kernel/process_32.c index c8890b8b772a..54bb813bc29b 100644 --- a/arch/x86/kernel/process_32.c +++ b/arch/x86/kernel/process_32.c @@ -259,14 +259,6 @@ static void mwait_idle(void) mwait_idle_with_hints(0, 0); } -static int __cpuinit mwait_usable(const struct cpuinfo_x86 *c) -{ - if (force_mwait) - return 1; - /* Any C1 states supported? */ - return c->cpuid_level >= 5 && ((cpuid_edx(5) >> 4) & 0xf) > 0; -} - void __cpuinit select_idle_routine(const struct cpuinfo_x86 *c) { static int selected; @@ -279,7 +271,7 @@ void __cpuinit select_idle_routine(const struct cpuinfo_x86 *c) " performance may degrade.\n"); } #endif - if (cpu_has(c, X86_FEATURE_MWAIT) && mwait_usable(c)) { + if (cpu_has(c, X86_FEATURE_MWAIT)) { /* * Skip, if setup has overridden idle. * One CPU supports mwait => All CPUs supports mwait diff --git a/arch/x86/kernel/process_64.c b/arch/x86/kernel/process_64.c index 1316f1cb7d87..fbb171fc2bee 100644 --- a/arch/x86/kernel/process_64.c +++ b/arch/x86/kernel/process_64.c @@ -254,15 +254,6 @@ static void mwait_idle(void) } } - -static int __cpuinit mwait_usable(const struct cpuinfo_x86 *c) -{ - if (force_mwait) - return 1; - /* Any C1 states supported? */ - return c->cpuid_level >= 5 && ((cpuid_edx(5) >> 4) & 0xf) > 0; -} - void __cpuinit select_idle_routine(const struct cpuinfo_x86 *c) { static int selected; @@ -275,7 +266,7 @@ void __cpuinit select_idle_routine(const struct cpuinfo_x86 *c) " performance may degrade.\n"); } #endif - if (cpu_has(c, X86_FEATURE_MWAIT) && mwait_usable(c)) { + if (cpu_has(c, X86_FEATURE_MWAIT)) { /* * Skip, if setup has overridden idle. * One CPU supports mwait => All CPUs supports mwait |