Home Home > GIT Browse
summaryrefslogtreecommitdiff
diff options
context:
space:
mode:
authorIngo Molnar <mingo@elte.hu>2008-06-19 16:32:14 +0200
committerGreg Kroah-Hartman <gregkh@suse.de>2008-06-21 22:24:57 -0700
commit384353364373c7c9f8134a847a35e27642cb6dae (patch)
treed4191107a9bcd8a1d7288330673054272c3ace15
parentb2e4b1cc4a1bfa05582949065a2c97ce7ab3caa3 (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.c10
-rw-r--r--arch/x86/kernel/process_64.c11
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