diff options
| author | Suresh Siddha <suresh.b.siddha@intel.com> | 2010-09-30 21:19:07 -0400 |
|---|---|---|
| committer | Len Brown <len.brown@intel.com> | 2010-09-30 21:19:22 -0400 |
| commit | 6110a1f43c27b516e16d5ce8860fca50748c2a87 (patch) | |
| tree | 021233718337a4a72ba4715f4d0782d5253fec7c | |
| parent | 9587a678fa56ea6d7f39b048f24f5d03a89bf9b3 (diff) | |
intel_idle: Voluntary leave_mm before entering deeper
Avoid TLB flush IPIs for the cores in deeper c-states by voluntary leave_mm()
before entering into that state. CPUs tend to flush TLB in those c-states
anyways.
acpi_idle does this with C3-type states, but it was not caried over
when intel_idle was introduced. intel_idle can apply it
to C-states in addition to those that ACPI might export as C3...
Signed-off-by: Suresh Siddha <suresh.b.siddha@intel.com>
Signed-off-by: Len Brown <len.brown@intel.com>
| -rw-r--r-- | drivers/idle/intel_idle.c | 18 | ||||
| -rw-r--r-- | include/linux/cpuidle.h | 1 |
2 files changed, 15 insertions, 4 deletions
diff --git a/drivers/idle/intel_idle.c b/drivers/idle/intel_idle.c index 96bf38097996..0906fc5b69b9 100644 --- a/drivers/idle/intel_idle.c +++ b/drivers/idle/intel_idle.c @@ -108,7 +108,7 @@ static struct cpuidle_state nehalem_cstates[MWAIT_MAX_NUM_CSTATES] = { .name = "NHM-C3", .desc = "MWAIT 0x10", .driver_data = (void *) 0x10, - .flags = CPUIDLE_FLAG_TIME_VALID, + .flags = CPUIDLE_FLAG_TIME_VALID | CPUIDLE_FLAG_TLB_FLUSHED, .exit_latency = 20, .power_usage = 500, .target_residency = 80, @@ -117,7 +117,7 @@ static struct cpuidle_state nehalem_cstates[MWAIT_MAX_NUM_CSTATES] = { .name = "NHM-C6", .desc = "MWAIT 0x20", .driver_data = (void *) 0x20, - .flags = CPUIDLE_FLAG_TIME_VALID, + .flags = CPUIDLE_FLAG_TIME_VALID | CPUIDLE_FLAG_TLB_FLUSHED, .exit_latency = 200, .power_usage = 350, .target_residency = 800, @@ -149,7 +149,7 @@ static struct cpuidle_state atom_cstates[MWAIT_MAX_NUM_CSTATES] = { .name = "ATM-C4", .desc = "MWAIT 0x30", .driver_data = (void *) 0x30, - .flags = CPUIDLE_FLAG_TIME_VALID, + .flags = CPUIDLE_FLAG_TIME_VALID | CPUIDLE_FLAG_TLB_FLUSHED, .exit_latency = 100, .power_usage = 250, .target_residency = 400, @@ -159,7 +159,7 @@ static struct cpuidle_state atom_cstates[MWAIT_MAX_NUM_CSTATES] = { .name = "ATM-C6", .desc = "MWAIT 0x40", .driver_data = (void *) 0x40, - .flags = CPUIDLE_FLAG_TIME_VALID, + .flags = CPUIDLE_FLAG_TIME_VALID | CPUIDLE_FLAG_TLB_FLUSHED, .exit_latency = 200, .power_usage = 150, .target_residency = 800, @@ -185,6 +185,16 @@ static int intel_idle(struct cpuidle_device *dev, struct cpuidle_state *state) local_irq_disable(); + /* + * If the state flag indicates that the TLB will be flushed or if this + * is the deepest c-state supported, do a voluntary leave mm to avoid + * costly and mostly unnecessary wakeups for flushing the user TLB's + * associated with the active mm. + */ + if (state->flags & CPUIDLE_FLAG_TLB_FLUSHED || + (&dev->states[dev->state_count - 1] == state)) + leave_mm(cpu); + if (!(lapic_timer_reliable_states & (1 << (cstate)))) clockevents_notify(CLOCK_EVT_NOTIFY_BROADCAST_ENTER, &cpu); diff --git a/include/linux/cpuidle.h b/include/linux/cpuidle.h index 36ca9721a0c2..1be416bbbb82 100644 --- a/include/linux/cpuidle.h +++ b/include/linux/cpuidle.h @@ -53,6 +53,7 @@ struct cpuidle_state { #define CPUIDLE_FLAG_BALANCED (0x40) /* medium latency, moderate savings */ #define CPUIDLE_FLAG_DEEP (0x80) /* high latency, large savings */ #define CPUIDLE_FLAG_IGNORE (0x100) /* ignore during this idle period */ +#define CPUIDLE_FLAG_TLB_FLUSHED (0x200) /* tlb will be flushed */ #define CPUIDLE_DRIVER_FLAGS_MASK (0xFFFF0000) |