From 541adf7cd937b3895c7645406a9b060504df453b Mon Sep 17 00:00:00 2001 From: Len Brown Date: Sat, 22 May 2010 17:03:29 -0400 Subject: ACPI: allow a native cpuidle driver to displace ACPI The ACPI driver would fail probe when it found that another driver had previously registered with cpuidle. But this is a natural situation, as a native hardware cpuidle driver should be able to bind instead of ACPI, and the ACPI processor driver should be able to handle yielding control of C-states while still handling P-states and T-states. Add a KERN_DEBUG line showing when acpi_idle does successfully register. Signed-off-by: Len Brown --- drivers/acpi/processor_driver.c | 11 ++++++----- 1 file changed, 6 insertions(+), 5 deletions(-) (limited to 'drivers/acpi') diff --git a/drivers/acpi/processor_driver.c b/drivers/acpi/processor_driver.c index 5675d97..deefa85 100644 --- a/drivers/acpi/processor_driver.c +++ b/drivers/acpi/processor_driver.c @@ -616,7 +616,8 @@ static int __cpuinit acpi_processor_add(struct acpi_device *device) acpi_processor_get_limit_info(pr); - acpi_processor_power_init(pr, device); + if (cpuidle_get_driver() == &acpi_idle_driver) + acpi_processor_power_init(pr, device); pr->cdev = thermal_cooling_device_register("Processor", device, &processor_cooling_ops); @@ -920,9 +921,10 @@ static int __init acpi_processor_init(void) if (!acpi_processor_dir) return -ENOMEM; #endif - result = cpuidle_register_driver(&acpi_idle_driver); - if (result < 0) - goto out_proc; + + if (!cpuidle_register_driver(&acpi_idle_driver)) + printk(KERN_DEBUG "ACPI: %s registered with cpuidle\n", + acpi_idle_driver.name); result = acpi_bus_register_driver(&acpi_processor_driver); if (result < 0) @@ -941,7 +943,6 @@ static int __init acpi_processor_init(void) out_cpuidle: cpuidle_unregister_driver(&acpi_idle_driver); -out_proc: #ifdef CONFIG_ACPI_PROCFS remove_proc_entry(ACPI_PROCESSOR_CLASS, acpi_root_dir); #endif -- cgit v1.1 From a7d27c37533524e23bbdc9ba1d78e3241b7483ea Mon Sep 17 00:00:00 2001 From: Len Brown Date: Mon, 24 May 2010 11:41:00 -0400 Subject: acpi_pad: uses MONITOR/MWAIT, so it doesn't need to clear TS_POLLING api_pad exclusively uses MONITOR/MWAIT to sleep in idle, so it does not need the wakeup IPI during idle sleep that is provoked by clearing TS_POLLING. Signed-off-by: Len Brown Cc: Shaohua Li --- drivers/acpi/acpi_pad.c | 9 --------- 1 file changed, 9 deletions(-) (limited to 'drivers/acpi') diff --git a/drivers/acpi/acpi_pad.c b/drivers/acpi/acpi_pad.c index 6212213..7edf053 100644 --- a/drivers/acpi/acpi_pad.c +++ b/drivers/acpi/acpi_pad.c @@ -168,13 +168,6 @@ static int power_saving_thread(void *data) do_sleep = 0; - current_thread_info()->status &= ~TS_POLLING; - /* - * TS_POLLING-cleared state must be visible before we test - * NEED_RESCHED: - */ - smp_mb(); - expire_time = jiffies + HZ * (100 - idle_pct) / 100; while (!need_resched()) { @@ -200,8 +193,6 @@ static int power_saving_thread(void *data) } } - current_thread_info()->status |= TS_POLLING; - /* * current sched_rt has threshold for rt task running time. * When a rt task uses 95% CPU time, the rt thread will be -- cgit v1.1 From 02cf4f9808382af7265cafc33dc86ec5875526aa Mon Sep 17 00:00:00 2001 From: Len Brown Date: Mon, 24 May 2010 14:27:44 -0400 Subject: ACPI: acpi_idle: touch TS_POLLING only in the non-MWAIT case commit d306ebc28649b89877a22158fe0076f06cc46f60 (ACPI: Be in TS_POLLING state during mwait based C-state entry) fixed an important power & performance issue where ACPI c2 and c3 C-states were clearing TS_POLLING even when using MWAIT (ACPI_STATE_FFH). That bug had been causing us to receive redundant scheduling interrups when we had already been woken up by MONITOR/MWAIT. Following up on that... In the MWAIT case, we don't have to subsequently check need_resched(), as that c heck was there for the TS_POLLING-clearing case. Note that not only does the cpuidle calling function already check need_resched() before calling us, the low-level entry into monitor/mwait calls it twice -- guaranteeing that a write to the trigger address can not go un-noticed. Also, in this case, we don't have to set TS_POLLING when we wake, because we never cleared it. Signed-off-by: Len Brown Acked-by: Venkatesh Pallipadi --- drivers/acpi/processor_idle.c | 28 ++++++++++++++++------------ 1 file changed, 16 insertions(+), 12 deletions(-) (limited to 'drivers/acpi') diff --git a/drivers/acpi/processor_idle.c b/drivers/acpi/processor_idle.c index 5939e7f..a4166e2 100644 --- a/drivers/acpi/processor_idle.c +++ b/drivers/acpi/processor_idle.c @@ -881,6 +881,7 @@ static int acpi_idle_enter_simple(struct cpuidle_device *dev, return(acpi_idle_enter_c1(dev, state)); local_irq_disable(); + if (cx->entry_method != ACPI_CSTATE_FFH) { current_thread_info()->status &= ~TS_POLLING; /* @@ -888,12 +889,12 @@ static int acpi_idle_enter_simple(struct cpuidle_device *dev, * NEED_RESCHED: */ smp_mb(); - } - if (unlikely(need_resched())) { - current_thread_info()->status |= TS_POLLING; - local_irq_enable(); - return 0; + if (unlikely(need_resched())) { + current_thread_info()->status |= TS_POLLING; + local_irq_enable(); + return 0; + } } /* @@ -918,7 +919,8 @@ static int acpi_idle_enter_simple(struct cpuidle_device *dev, sched_clock_idle_wakeup_event(sleep_ticks*PM_TIMER_TICK_NS); local_irq_enable(); - current_thread_info()->status |= TS_POLLING; + if (cx->entry_method != ACPI_CSTATE_FFH) + current_thread_info()->status |= TS_POLLING; cx->usage++; @@ -968,6 +970,7 @@ static int acpi_idle_enter_bm(struct cpuidle_device *dev, } local_irq_disable(); + if (cx->entry_method != ACPI_CSTATE_FFH) { current_thread_info()->status &= ~TS_POLLING; /* @@ -975,12 +978,12 @@ static int acpi_idle_enter_bm(struct cpuidle_device *dev, * NEED_RESCHED: */ smp_mb(); - } - if (unlikely(need_resched())) { - current_thread_info()->status |= TS_POLLING; - local_irq_enable(); - return 0; + if (unlikely(need_resched())) { + current_thread_info()->status |= TS_POLLING; + local_irq_enable(); + return 0; + } } acpi_unlazy_tlb(smp_processor_id()); @@ -1032,7 +1035,8 @@ static int acpi_idle_enter_bm(struct cpuidle_device *dev, sched_clock_idle_wakeup_event(sleep_ticks*PM_TIMER_TICK_NS); local_irq_enable(); - current_thread_info()->status |= TS_POLLING; + if (cx->entry_method != ACPI_CSTATE_FFH) + current_thread_info()->status |= TS_POLLING; cx->usage++; -- cgit v1.1 From 2671717265ae6e720a9ba5f13fbec3a718983b65 Mon Sep 17 00:00:00 2001 From: Len Brown Date: Mon, 8 Mar 2010 14:07:30 -0500 Subject: intel_idle: native hardware cpuidle driver for latest Intel processors This EXPERIMENTAL driver supersedes acpi_idle on Intel Atom Processors, Intel Core i3/i5/i7 Processors and associated Intel Xeon processors. It does not support the Intel Core2 processor or earlier. For kernels configured with ACPI, CONFIG_INTEL_IDLE=y allows intel_idle to probe before the ACPI processor driver. Booting with "intel_idle.max_cstate=0" disables intel_idle and the system will fall back on ACPI's "acpi_idle". Typical Linux distributions load ACPI processor module early, making CONFIG_INTEL_IDLE=m not easily useful on ACPI platforms. intel_idle probes all processors at module_init time. Processors that are hot-added later will be limited to using C1 in idle. Signed-off-by: Len Brown --- drivers/acpi/processor_driver.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) (limited to 'drivers/acpi') diff --git a/drivers/acpi/processor_driver.c b/drivers/acpi/processor_driver.c index deefa85..b1034a9 100644 --- a/drivers/acpi/processor_driver.c +++ b/drivers/acpi/processor_driver.c @@ -922,9 +922,13 @@ static int __init acpi_processor_init(void) return -ENOMEM; #endif - if (!cpuidle_register_driver(&acpi_idle_driver)) + if (!cpuidle_register_driver(&acpi_idle_driver)) { printk(KERN_DEBUG "ACPI: %s registered with cpuidle\n", acpi_idle_driver.name); + } else { + printk(KERN_DEBUG "ACPI: acpi_idle yielding to %s", + cpuidle_get_driver()->name); + } result = acpi_bus_register_driver(&acpi_processor_driver); if (result < 0) -- cgit v1.1