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 <len.brown@intel.com>
This commit is contained in:
Len Brown
parent
02cf4f9808
commit
2671717265
6 changed files with 486 additions and 2 deletions
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@ -2850,6 +2850,13 @@ T: git git://git.kernel.org/pub/scm/linux/kernel/git/dtor/input.git
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S: Maintained
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F: drivers/input/
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INTEL IDLE DRIVER
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M: Len Brown <lenb@kernel.org>
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L: linux-pm@lists.linux-foundation.org
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T: git git://git.kernel.org/pub/scm/linux/kernel/git/lenb/linux-idle-2.6.git
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S: Supported
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F: drivers/idle/intel_idle.c
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INTEL FRAMEBUFFER DRIVER (excluding 810 and 815)
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M: Maik Broemme <mbroemme@plusserver.de>
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L: linux-fbdev@vger.kernel.org
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@ -10,6 +10,7 @@ obj-$(CONFIG_PCI) += pci/
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obj-$(CONFIG_PARISC) += parisc/
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obj-$(CONFIG_RAPIDIO) += rapidio/
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obj-y += video/
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obj-y += idle/
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obj-$(CONFIG_ACPI) += acpi/
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obj-$(CONFIG_SFI) += sfi/
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# PnP must come after ACPI since it will eventually need to check if acpi
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@ -91,7 +92,6 @@ obj-$(CONFIG_EISA) += eisa/
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obj-y += lguest/
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obj-$(CONFIG_CPU_FREQ) += cpufreq/
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obj-$(CONFIG_CPU_IDLE) += cpuidle/
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obj-y += idle/
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obj-$(CONFIG_MMC) += mmc/
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obj-$(CONFIG_MEMSTICK) += memstick/
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obj-$(CONFIG_NEW_LEDS) += leds/
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@ -922,9 +922,13 @@ static int __init acpi_processor_init(void)
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return -ENOMEM;
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#endif
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if (!cpuidle_register_driver(&acpi_idle_driver))
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if (!cpuidle_register_driver(&acpi_idle_driver)) {
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printk(KERN_DEBUG "ACPI: %s registered with cpuidle\n",
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acpi_idle_driver.name);
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} else {
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printk(KERN_DEBUG "ACPI: acpi_idle yielding to %s",
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cpuidle_get_driver()->name);
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}
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result = acpi_bus_register_driver(&acpi_processor_driver);
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if (result < 0)
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@ -1,3 +1,14 @@
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config INTEL_IDLE
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tristate "Cpuidle Driver for Intel Processors"
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depends on CPU_IDLE
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depends on X86
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depends on CPU_SUP_INTEL
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depends on EXPERIMENTAL
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help
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Enable intel_idle, a cpuidle driver that includes knowledge of
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native Intel hardware idle features. The acpi_idle driver
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can be configured at the same time, in order to handle
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processors intel_idle does not support.
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menu "Memory power savings"
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depends on X86_64
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@ -1,2 +1,3 @@
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obj-$(CONFIG_I7300_IDLE) += i7300_idle.o
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obj-$(CONFIG_INTEL_IDLE) += intel_idle.o
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461
drivers/idle/intel_idle.c
Executable file
461
drivers/idle/intel_idle.c
Executable file
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@ -0,0 +1,461 @@
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/*
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* intel_idle.c - native hardware idle loop for modern Intel processors
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*
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* Copyright (c) 2010, Intel Corporation.
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* Len Brown <len.brown@intel.com>
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*
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* This program is free software; you can redistribute it and/or modify it
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* under the terms and conditions of the GNU General Public License,
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* version 2, as published by the Free Software Foundation.
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*
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* This program is distributed in the hope it will be useful, but WITHOUT
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* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
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* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
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* more details.
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*
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* You should have received a copy of the GNU General Public License along with
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* this program; if not, write to the Free Software Foundation, Inc.,
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* 51 Franklin St - Fifth Floor, Boston, MA 02110-1301 USA.
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*/
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/*
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* intel_idle is a cpuidle driver that loads on specific Intel processors
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* in lieu of the legacy ACPI processor_idle driver. The intent is to
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* make Linux more efficient on these processors, as intel_idle knows
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* more than ACPI, as well as make Linux more immune to ACPI BIOS bugs.
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*/
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/*
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* Design Assumptions
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*
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* All CPUs have same idle states as boot CPU
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*
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* Chipset BM_STS (bus master status) bit is a NOP
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* for preventing entry into deep C-stats
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*/
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/*
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* Known limitations
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*
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* The driver currently initializes for_each_online_cpu() upon modprobe.
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* It it unaware of subsequent processors hot-added to the system.
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* This means that if you boot with maxcpus=n and later online
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* processors above n, those processors will use C1 only.
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*
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* ACPI has a .suspend hack to turn off deep c-statees during suspend
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* to avoid complications with the lapic timer workaround.
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* Have not seen issues with suspend, but may need same workaround here.
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*
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* There is currently no kernel-based automatic probing/loading mechanism
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* if the driver is built as a module.
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*/
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/* un-comment DEBUG to enable pr_debug() statements */
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#define DEBUG
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#include <linux/kernel.h>
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#include <linux/cpuidle.h>
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#include <linux/clockchips.h>
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#include <linux/hrtimer.h> /* ktime_get_real() */
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#include <trace/events/power.h>
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#include <linux/sched.h>
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#define INTEL_IDLE_VERSION "0.4"
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#define PREFIX "intel_idle: "
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#define MWAIT_SUBSTATE_MASK (0xf)
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#define MWAIT_CSTATE_MASK (0xf)
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#define MWAIT_SUBSTATE_SIZE (4)
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#define MWAIT_MAX_NUM_CSTATES 8
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#define CPUID_MWAIT_LEAF (5)
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#define CPUID5_ECX_EXTENSIONS_SUPPORTED (0x1)
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#define CPUID5_ECX_INTERRUPT_BREAK (0x2)
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static struct cpuidle_driver intel_idle_driver = {
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.name = "intel_idle",
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.owner = THIS_MODULE,
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};
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/* intel_idle.max_cstate=0 disables driver */
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static int max_cstate = MWAIT_MAX_NUM_CSTATES - 1;
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static int power_policy = 7; /* 0 = max perf; 15 = max powersave */
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static unsigned int substates;
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static int (*choose_substate)(int);
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/* Reliable LAPIC Timer States, bit 1 for C1 etc. */
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static unsigned int lapic_timer_reliable_states;
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static struct cpuidle_device *intel_idle_cpuidle_devices;
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static int intel_idle(struct cpuidle_device *dev, struct cpuidle_state *state);
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static struct cpuidle_state *cpuidle_state_table;
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/*
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* States are indexed by the cstate number,
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* which is also the index into the MWAIT hint array.
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* Thus C0 is a dummy.
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*/
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static struct cpuidle_state nehalem_cstates[MWAIT_MAX_NUM_CSTATES] = {
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{ /* MWAIT C0 */ },
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{ /* MWAIT C1 */
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.name = "NHM-C1",
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.desc = "MWAIT 0x00",
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.driver_data = (void *) 0x00,
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.flags = CPUIDLE_FLAG_TIME_VALID,
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.exit_latency = 3,
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.power_usage = 1000,
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.target_residency = 6,
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.enter = &intel_idle },
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{ /* MWAIT C2 */
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.name = "NHM-C3",
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.desc = "MWAIT 0x10",
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.driver_data = (void *) 0x10,
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.flags = CPUIDLE_FLAG_TIME_VALID,
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.exit_latency = 20,
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.power_usage = 500,
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.target_residency = 80,
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.enter = &intel_idle },
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{ /* MWAIT C3 */
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.name = "NHM-C6",
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.desc = "MWAIT 0x20",
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.driver_data = (void *) 0x20,
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.flags = CPUIDLE_FLAG_TIME_VALID,
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.exit_latency = 200,
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.power_usage = 350,
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.target_residency = 800,
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.enter = &intel_idle },
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};
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static struct cpuidle_state atom_cstates[MWAIT_MAX_NUM_CSTATES] = {
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{ /* MWAIT C0 */ },
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{ /* MWAIT C1 */
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.name = "ATM-C1",
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.desc = "MWAIT 0x00",
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.driver_data = (void *) 0x00,
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.flags = CPUIDLE_FLAG_TIME_VALID,
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.exit_latency = 1,
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.power_usage = 1000,
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.target_residency = 4,
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.enter = &intel_idle },
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{ /* MWAIT C2 */
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.name = "ATM-C2",
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.desc = "MWAIT 0x10",
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.driver_data = (void *) 0x10,
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.flags = CPUIDLE_FLAG_TIME_VALID,
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.exit_latency = 20,
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.power_usage = 500,
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.target_residency = 80,
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.enter = &intel_idle },
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{ /* MWAIT C3 */ },
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{ /* MWAIT C4 */
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.name = "ATM-C4",
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.desc = "MWAIT 0x30",
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.driver_data = (void *) 0x30,
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.flags = CPUIDLE_FLAG_TIME_VALID,
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.exit_latency = 100,
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.power_usage = 250,
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.target_residency = 400,
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.enter = &intel_idle },
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{ /* MWAIT C5 */ },
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{ /* MWAIT C6 */
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.name = "ATM-C6",
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.desc = "MWAIT 0x40",
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.driver_data = (void *) 0x40,
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.flags = CPUIDLE_FLAG_TIME_VALID,
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.exit_latency = 200,
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.power_usage = 150,
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.target_residency = 800,
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.enter = NULL }, /* disabled */
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};
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/*
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* choose_tunable_substate()
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*
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* Run-time decision on which C-state substate to invoke
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* If power_policy = 0, choose shallowest substate (0)
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* If power_policy = 15, choose deepest substate
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* If power_policy = middle, choose middle substate etc.
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*/
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static int choose_tunable_substate(int cstate)
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{
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unsigned int num_substates;
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unsigned int substate_choice;
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power_policy &= 0xF; /* valid range: 0-15 */
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cstate &= 7; /* valid range: 0-7 */
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num_substates = (substates >> ((cstate) * 4)) & MWAIT_SUBSTATE_MASK;
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if (num_substates <= 1)
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return 0;
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substate_choice = ((power_policy + (power_policy + 1) *
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(num_substates - 1)) / 16);
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return substate_choice;
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}
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/*
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* choose_zero_substate()
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*/
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static int choose_zero_substate(int cstate)
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{
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return 0;
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}
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/**
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* intel_idle
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* @dev: cpuidle_device
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* @state: cpuidle state
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*
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*/
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static int intel_idle(struct cpuidle_device *dev, struct cpuidle_state *state)
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{
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unsigned long ecx = 1; /* break on interrupt flag */
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unsigned long eax = (unsigned long)cpuidle_get_statedata(state);
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unsigned int cstate;
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ktime_t kt_before, kt_after;
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s64 usec_delta;
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int cpu = smp_processor_id();
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cstate = (((eax) >> MWAIT_SUBSTATE_SIZE) & MWAIT_CSTATE_MASK) + 1;
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eax = eax + (choose_substate)(cstate);
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local_irq_disable();
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if (!(lapic_timer_reliable_states & (1 << (cstate))))
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clockevents_notify(CLOCK_EVT_NOTIFY_BROADCAST_ENTER, &cpu);
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kt_before = ktime_get_real();
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stop_critical_timings();
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#ifndef MODULE
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trace_power_start(POWER_CSTATE, (eax >> 4) + 1);
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#endif
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if (!need_resched()) {
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__monitor((void *)¤t_thread_info()->flags, 0, 0);
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smp_mb();
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if (!need_resched())
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__mwait(eax, ecx);
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}
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start_critical_timings();
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kt_after = ktime_get_real();
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usec_delta = ktime_to_us(ktime_sub(kt_after, kt_before));
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local_irq_enable();
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if (!(lapic_timer_reliable_states & (1 << (cstate))))
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clockevents_notify(CLOCK_EVT_NOTIFY_BROADCAST_EXIT, &cpu);
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return usec_delta;
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}
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/*
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* intel_idle_probe()
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*/
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static int intel_idle_probe(void)
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{
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unsigned int eax, ebx, ecx, edx;
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if (max_cstate == 0) {
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pr_debug(PREFIX "disabled\n");
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return -EPERM;
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}
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if (boot_cpu_data.x86_vendor != X86_VENDOR_INTEL)
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return -ENODEV;
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if (!boot_cpu_has(X86_FEATURE_MWAIT))
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return -ENODEV;
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if (boot_cpu_data.cpuid_level < CPUID_MWAIT_LEAF)
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return -ENODEV;
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cpuid(CPUID_MWAIT_LEAF, &eax, &ebx, &ecx, &edx);
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if (!(ecx & CPUID5_ECX_EXTENSIONS_SUPPORTED) ||
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!(ecx & CPUID5_ECX_INTERRUPT_BREAK))
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return -ENODEV;
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#ifdef DEBUG
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if (substates == 0) /* can over-ride via modparam */
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#endif
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substates = edx;
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pr_debug(PREFIX "MWAIT substates: 0x%x\n", substates);
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if (boot_cpu_has(X86_FEATURE_ARAT)) /* Always Reliable APIC Timer */
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lapic_timer_reliable_states = 0xFFFFFFFF;
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if (boot_cpu_data.x86 != 6) /* family 6 */
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return -ENODEV;
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switch (boot_cpu_data.x86_model) {
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case 0x1A: /* Core i7, Xeon 5500 series */
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case 0x1E: /* Core i7 and i5 Processor - Lynnfield Jasper Forest */
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case 0x1F: /* Core i7 and i5 Processor - Nehalem */
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case 0x2E: /* Nehalem-EX Xeon */
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lapic_timer_reliable_states = (1 << 1); /* C1 */
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case 0x25: /* Westmere */
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case 0x2C: /* Westmere */
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cpuidle_state_table = nehalem_cstates;
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choose_substate = choose_tunable_substate;
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break;
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case 0x1C: /* 28 - Atom Processor */
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lapic_timer_reliable_states = (1 << 2) | (1 << 1); /* C2, C1 */
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cpuidle_state_table = atom_cstates;
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choose_substate = choose_zero_substate;
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break;
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#ifdef FUTURE_USE
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case 0x17: /* 23 - Core 2 Duo */
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lapic_timer_reliable_states = (1 << 2) | (1 << 1); /* C2, C1 */
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#endif
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default:
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pr_debug(PREFIX "does not run on family %d model %d\n",
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boot_cpu_data.x86, boot_cpu_data.x86_model);
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return -ENODEV;
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}
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pr_debug(PREFIX "v" INTEL_IDLE_VERSION
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" model 0x%X\n", boot_cpu_data.x86_model);
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pr_debug(PREFIX "lapic_timer_reliable_states 0x%x\n",
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lapic_timer_reliable_states);
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return 0;
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}
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/*
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* intel_idle_cpuidle_devices_uninit()
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* unregister, free cpuidle_devices
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*/
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static void intel_idle_cpuidle_devices_uninit(void)
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{
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int i;
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struct cpuidle_device *dev;
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for_each_online_cpu(i) {
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dev = per_cpu_ptr(intel_idle_cpuidle_devices, i);
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cpuidle_unregister_device(dev);
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}
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free_percpu(intel_idle_cpuidle_devices);
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return;
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}
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/*
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* intel_idle_cpuidle_devices_init()
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* allocate, initialize, register cpuidle_devices
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*/
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static int intel_idle_cpuidle_devices_init(void)
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{
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int i, cstate;
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struct cpuidle_device *dev;
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intel_idle_cpuidle_devices = alloc_percpu(struct cpuidle_device);
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if (intel_idle_cpuidle_devices == NULL)
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return -ENOMEM;
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for_each_online_cpu(i) {
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dev = per_cpu_ptr(intel_idle_cpuidle_devices, i);
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dev->state_count = 1;
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for (cstate = 1; cstate < MWAIT_MAX_NUM_CSTATES; ++cstate) {
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int num_substates;
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if (cstate > max_cstate) {
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printk(PREFIX "max_cstate %d reached\n",
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max_cstate);
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break;
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}
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||||
|
||||
/* does the state exist in CPUID.MWAIT? */
|
||||
num_substates = (substates >> ((cstate) * 4))
|
||||
& MWAIT_SUBSTATE_MASK;
|
||||
if (num_substates == 0)
|
||||
continue;
|
||||
/* is the state not enabled? */
|
||||
if (cpuidle_state_table[cstate].enter == NULL) {
|
||||
/* does the driver not know about the state? */
|
||||
if (*cpuidle_state_table[cstate].name == '\0')
|
||||
pr_debug(PREFIX "unaware of model 0x%x"
|
||||
" MWAIT %d please"
|
||||
" contact lenb@kernel.org",
|
||||
boot_cpu_data.x86_model, cstate);
|
||||
continue;
|
||||
}
|
||||
|
||||
if ((cstate > 2) &&
|
||||
!boot_cpu_has(X86_FEATURE_NONSTOP_TSC))
|
||||
mark_tsc_unstable("TSC halts in idle"
|
||||
" states deeper than C2");
|
||||
|
||||
dev->states[dev->state_count] = /* structure copy */
|
||||
cpuidle_state_table[cstate];
|
||||
|
||||
dev->state_count += 1;
|
||||
}
|
||||
|
||||
dev->cpu = i;
|
||||
if (cpuidle_register_device(dev)) {
|
||||
pr_debug(PREFIX "cpuidle_register_device %d failed!\n",
|
||||
i);
|
||||
intel_idle_cpuidle_devices_uninit();
|
||||
return -EIO;
|
||||
}
|
||||
}
|
||||
|
||||
return 0;
|
||||
}
|
||||
|
||||
|
||||
static int __init intel_idle_init(void)
|
||||
{
|
||||
int retval;
|
||||
|
||||
retval = intel_idle_probe();
|
||||
if (retval)
|
||||
return retval;
|
||||
|
||||
retval = cpuidle_register_driver(&intel_idle_driver);
|
||||
if (retval) {
|
||||
printk(KERN_DEBUG PREFIX "intel_idle yielding to %s",
|
||||
cpuidle_get_driver()->name);
|
||||
return retval;
|
||||
}
|
||||
|
||||
retval = intel_idle_cpuidle_devices_init();
|
||||
if (retval) {
|
||||
cpuidle_unregister_driver(&intel_idle_driver);
|
||||
return retval;
|
||||
}
|
||||
|
||||
return 0;
|
||||
}
|
||||
|
||||
static void __exit intel_idle_exit(void)
|
||||
{
|
||||
intel_idle_cpuidle_devices_uninit();
|
||||
cpuidle_unregister_driver(&intel_idle_driver);
|
||||
|
||||
return;
|
||||
}
|
||||
|
||||
module_init(intel_idle_init);
|
||||
module_exit(intel_idle_exit);
|
||||
|
||||
module_param(power_policy, int, 0644);
|
||||
module_param(max_cstate, int, 0444);
|
||||
#ifdef DEBUG
|
||||
module_param(substates, int, 0444);
|
||||
#endif
|
||||
|
||||
MODULE_AUTHOR("Len Brown <len.brown@intel.com>");
|
||||
MODULE_DESCRIPTION("Cpuidle driver for Intel Hardware v" INTEL_IDLE_VERSION);
|
||||
MODULE_LICENSE("GPL");
|
||||
Loading…
Reference in a new issue