29 Nov, 2019
1 commit
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Adjust indentation from spaces to tab (+optional two spaces) as in
coding style with command like:
$ sed -e 's/^ /\t/' -i */KconfigSigned-off-by: Krzysztof Kozlowski
Signed-off-by: Rafael J. Wysocki
30 Jul, 2019
2 commits
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The cpuidle_haltpoll governor, in conjunction with the haltpoll cpuidle
driver, allows guest vcpus to poll for a specified amount of time before
halting.
This provides the following benefits to host side polling:1) The POLL flag is set while polling is performed, which allows
a remote vCPU to avoid sending an IPI (and the associated
cost of handling the IPI) when performing a wakeup.2) The VM-exit cost can be avoided.
The downside of guest side polling is that polling is performed
even with other runnable tasks in the host.Results comparing halt_poll_ns and server/client application
where a small packet is ping-ponged:host --> 31.33
halt_poll_ns=300000 / no guest busy spin --> 33.40 (93.8%)
halt_poll_ns=0 / guest_halt_poll_ns=300000 --> 32.73 (95.7%)For the SAP HANA benchmarks (where idle_spin is a parameter
of the previous version of the patch, results should be the
same):hpns == halt_poll_ns
idle_spin=0/ idle_spin=800/ idle_spin=0/
hpns=200000 hpns=0 hpns=800000
DeleteC06T03 (100 thread) 1.76 1.71 (-3%) 1.78 (+1%)
InsertC16T02 (100 thread) 2.14 2.07 (-3%) 2.18 (+1.8%)
DeleteC00T01 (1 thread) 1.34 1.28 (-4.5%) 1.29 (-3.7%)
UpdateC00T03 (1 thread) 4.72 4.18 (-12%) 4.53 (-5%)Signed-off-by: Marcelo Tosatti
Signed-off-by: Rafael J. Wysocki -
Add a cpuidle driver that calls the architecture default_idle routine.
To be used in conjunction with the haltpoll governor.
Signed-off-by: Marcelo Tosatti
Signed-off-by: Rafael J. Wysocki
21 May, 2019
1 commit
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Add SPDX license identifiers to all Make/Kconfig files which:
- Have no license information of any form
These files fall under the project license, GPL v2 only. The resulting SPDX
license identifier is:GPL-2.0-only
Signed-off-by: Thomas Gleixner
Signed-off-by: Greg Kroah-Hartman
17 Jan, 2019
1 commit
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The venerable menu governor does some things that are quite
questionable in my view.First, it includes timer wakeups in the pattern detection data and
mixes them up with wakeups from other sources which in some cases
causes it to expect what essentially would be a timer wakeup in a
time frame in which no timer wakeups are possible (because it knows
the time until the next timer event and that is later than the
expected wakeup time).Second, it uses the extra exit latency limit based on the predicted
idle duration and depending on the number of tasks waiting on I/O,
even though those tasks may run on a different CPU when they are
woken up. Moreover, the time ranges used by it for the sleep length
correction factors depend on whether or not there are tasks waiting
on I/O, which again doesn't imply anything in particular, and they
are not correlated to the list of available idle states in any way
whatever.Also, the pattern detection code in menu may end up considering
values that are too large to matter at all, in which cases running
it is a waste of time.A major rework of the menu governor would be required to address
these issues and the performance of at least some workloads (tuned
specifically to the current behavior of the menu governor) is likely
to suffer from that. It is thus better to introduce an entirely new
governor without them and let everybody use the governor that works
better with their actual workloads.The new governor introduced here, the timer events oriented (TEO)
governor, uses the same basic strategy as menu: it always tries to
find the deepest idle state that can be used in the given conditions.
However, it applies a different approach to that problem.First, it doesn't use "correction factors" for the time till the
closest timer, but instead it tries to correlate the measured idle
duration values with the available idle states and use that
information to pick up the idle state that is most likely to "match"
the upcoming CPU idle interval.Second, it doesn't take the number of "I/O waiters" into account at
all and the pattern detection code in it avoids taking timer wakeups
into account. It also only uses idle duration values less than the
current time till the closest timer (with the tick excluded) for that
purpose.Signed-off-by: Rafael J. Wysocki
Acked-by: Daniel Lezcano
16 Jan, 2016
1 commit
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Since commit d6f346f2d2 (cpuidle: improve governor Kconfig options)
the best cpuidle governor is selected automatically. There is little
point in additionally selecting the other one as it will not be used,
so don't select both governors by default.Being able to select more than one governor is still good for
developers booting with cpuidle_sysfs_switch, though.This fixes the second half of kernel BZ #65531.
Link: https://bugzilla.kernel.org/show_bug.cgi?id=65531
Signed-off-by: Jean Delvare
Signed-off-by: Rafael J. Wysocki
24 Mar, 2015
1 commit
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ARM32 and ARM64 have the same DT definitions and the same approaches.
The generic ARM cpuidle driver can be put in common for those two
architectures.Signed-off-by: Daniel Lezcano
Acked-by: Kevin Hilman
Acked-by: Rob Herring
Acked-by: Lorenzo Pieralisi
Tested-by: Lorenzo Pieralisi
25 Sep, 2014
2 commits
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This patch implements a generic CPU idle driver for ARM64 machines.
It relies on the DT idle states infrastructure to initialize idle
states count and respective parameters. Current code assumes the driver
is managing idle states on all possible CPUs but can be easily
generalized to support heterogenous systems and build cpumasks at
runtime using MIDRs or DT cpu nodes compatible properties.The driver relies on the arm64 CPU operations to call the idle
initialization hook used to parse and save suspend back-end specific
idle states information upon probing.Idle state index 0 is always initialized as a simple wfi state, ie always
considered present and functional on all ARM64 platforms.Idle state indices higher than 0 trigger idle state entry by calling
the cpu_suspend function, that triggers the suspend operation through
the CPU operations suspend back-end hook. cpu_suspend passes the idle
state index as a parameter so that the CPU operations suspend back-end
can retrieve the required idle state data by using the idle state
index to execute a look-up on its internal data structures.Reviewed-by: Ashwin Chaugule
Reviewed-by: Catalin Marinas
Signed-off-by: Lorenzo Pieralisi
Signed-off-by: Daniel Lezcano -
On most common ARM systems, the low-power states a CPU can be put into are
not discoverable in HW and require device tree bindings to describe
power down suspend operations and idle states parameters.In order to enable DT based idle states and configure idle drivers, this
patch implements the bulk infrastructure required to parse the device tree
idle states bindings and initialize the corresponding CPUidle driver states
data.The parsing API accepts a start index that defines the first idle state
that should be initialized by the parsing code in order to give new and
legacy driver flexibility over which states should be parsed using the
new DT mechanism.The idle states node(s) is obtained from the phandle list of the first cpu
in the driver cpumask; the kernel checks that the idle state node phandle
is the same for all CPUs in the driver cpumask before declaring the idle state
as valid and start parsing its content.The idle state enter function pointer is initialized through DT match
structures passed in by the CPUidle driver, so that ARM legacy code can
cope with platform specific idle entry method based on compatible
string matching and the code used to initialize the enter function pointer
can be moved to the DT generic layer.Acked-by: Catalin Marinas
Acked-by: Daniel Lezcano
Signed-off-by: Lorenzo Pieralisi
Signed-off-by: Daniel Lezcano
29 Jul, 2014
1 commit
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Like the coupled idle state, it is not up to the user to set this option
but the driver to select it.Remove the interactive selection of this option.
Signed-off-by: Daniel Lezcano
Signed-off-by: Rafael J. Wysocki
28 May, 2014
1 commit
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This patch adds a cpuidle driver for systems based around the MIPS
Coherent Processing System (CPS) architecture. It supports four idle
states:- The standard MIPS wait instruction.
- The non-coherent wait, clock gated & power gated states exposed by
the recently added pm-cps layer.The pm-cps layer is used to enter all the deep idle states. Since cores
in the clock or power gated states cannot service interrupts, the
gic_send_ipi_single function is modified to send a power up command for
the appropriate core to the CPC in cases where the target CPU has marked
itself potentially incoherent.Signed-off-by: Paul Burton
29 Jan, 2014
1 commit
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Move the file from arch specific pseries/processor_idle.c
to drivers/cpuidle/cpuidle-pseries.c
Make the relevant Makefile and Kconfig changes.
Also, introduce Kconfig.powerpc in drivers/cpuidle
for all powerpc cpuidle drivers.Signed-off-by: Deepthi Dharwar
Signed-off-by: Benjamin Herrenschmidt
27 Jul, 2013
1 commit
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Add Kconfig.arm for ARM cpuidle drivers and moves calxeda, kirkwood
and zynq to Kconfig.arm. Like in the cpufreq menu, "CPU Idle" menu
is added to drivers/cpuidle/Kconfig.Signed-off-by: Sahara
04 Jul, 2013
1 commit
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Pull power management and ACPI updates from Rafael Wysocki:
"This time the total number of ACPI commits is slightly greater than
the number of cpufreq commits, but Viresh Kumar (who works on cpufreq)
remains the most active patch submitter.To me, the most significant change is the addition of offline/online
device operations to the driver core (with the Greg's blessing) and
the related modifications of the ACPI core hotplug code. Next are the
freezer updates from Colin Cross that should make the freezing of
tasks a bit less heavy weight.We also have a couple of regression fixes, a number of fixes for
issues that have not been identified as regressions, two new drivers
and a bunch of cleanups all over.Highlights:
- Hotplug changes to support graceful hot-removal failures.
It sometimes is necessary to fail device hot-removal operations
gracefully if they cannot be carried out completely. For example,
if memory from a memory module being hot-removed has been allocated
for the kernel's own use and cannot be moved elsewhere, it's
desirable to fail the hot-removal operation in a graceful way
rather than to crash the kernel, but currenty a success or a kernel
crash are the only possible outcomes of an attempted memory
hot-removal. Needless to say, that is not a very attractive
alternative and it had to be addressed.However, in order to make it work for memory, I first had to make
it work for CPUs and for this purpose I needed to modify the ACPI
processor driver. It's been split into two parts, a resident one
handling the low-level initialization/cleanup and a modular one
playing the actual driver's role (but it binds to the CPU system
device objects rather than to the ACPI device objects representing
processors). That's been sort of like a live brain surgery on a
patient who's riding a bike.So this is a little scary, but since we found and fixed a couple of
regressions it caused to happen during the early linux-next testing
(a month ago), nobody has complained.As a bonus we remove some duplicated ACPI hotplug code, because the
ACPI-based CPU hotplug is now going to use the common ACPI hotplug
code.- Lighter weight freezing of tasks.
These changes from Colin Cross and Mandeep Singh Baines are
targeted at making the freezing of tasks a bit less heavy weight
operation. They reduce the number of tasks woken up every time
during the freezing, by using the observation that the freezer
simply doesn't need to wake up some of them and wait for them all
to call refrigerator(). The time needed for the freezer to decide
to report a failure is reduced too.Also reintroduced is the check causing a lockdep warining to
trigger when try_to_freeze() is called with locks held (which is
generally unsafe and shouldn't happen).- cpufreq updates
First off, a commit from Srivatsa S Bhat fixes a resume regression
introduced during the 3.10 cycle causing some cpufreq sysfs
attributes to return wrong values to user space after resume. The
fix is kind of fresh, but also it's pretty obvious once Srivatsa
has identified the root cause.Second, we have a new freqdomain_cpus sysfs attribute for the
acpi-cpufreq driver to provide information previously available via
related_cpus. From Lan Tianyu.Finally, we fix a number of issues, mostly related to the
CPUFREQ_POSTCHANGE notifier and cpufreq Kconfig options and clean
up some code. The majority of changes from Viresh Kumar with bits
from Jacob Shin, Heiko Stübner, Xiaoguang Chen, Ezequiel Garcia,
Arnd Bergmann, and Tang Yuantian.- ACPICA update
A usual bunch of updates from the ACPICA upstream.
During the 3.4 cycle we introduced support for ACPI 5 extended
sleep registers, but they are only supposed to be used if the
HW-reduced mode bit is set in the FADT flags and the code attempted
to use them without checking that bit. That caused suspend/resume
regressions to happen on some systems. Fix from Lv Zheng causes
those registers to be used only if the HW-reduced mode bit is set.Apart from this some other ACPICA bugs are fixed and code cleanups
are made by Bob Moore, Tomasz Nowicki, Lv Zheng, Chao Guan, and
Zhang Rui.- cpuidle updates
New driver for Xilinx Zynq processors is added by Michal Simek.
Multidriver support simplification, addition of some missing
kerneldoc comments and Kconfig-related fixes come from Daniel
Lezcano.- ACPI power management updates
Changes to make suspend/resume work correctly in Xen guests from
Konrad Rzeszutek Wilk, sparse warning fix from Fengguang Wu and
cleanups and fixes of the ACPI device power state selection
routine.- ACPI documentation updates
Some previously missing pieces of ACPI documentation are added by
Lv Zheng and Aaron Lu (hopefully, that will help people to
uderstand how the ACPI subsystem works) and one outdated doc is
updated by Hanjun Guo.- Assorted ACPI updates
We finally nailed down the IA-64 issue that was the reason for
reverting commit 9f29ab11ddbf ("ACPI / scan: do not match drivers
against objects having scan handlers"), so we can fix it and move
the ACPI scan handler check added to the ACPI video driver back to
the core.A mechanism for adding CMOS RTC address space handlers is
introduced by Lan Tianyu to allow some EC-related breakage to be
fixed on some systems.A spec-compliant implementation of acpi_os_get_timer() is added by
Mika Westerberg.The evaluation of _STA is added to do_acpi_find_child() to avoid
situations in which a pointer to a disabled device object is
returned instead of an enabled one with the same _ADR value. From
Jeff Wu.Intel BayTrail PCH (Platform Controller Hub) support is added to
the ACPI driver for Intel Low-Power Subsystems (LPSS) and that
driver is modified to work around a couple of known BIOS issues.
Changes from Mika Westerberg and Heikki Krogerus.The EC driver is fixed by Vasiliy Kulikov to use get_user() and
put_user() instead of dereferencing user space pointers blindly.Code cleanups are made by Bjorn Helgaas, Nicholas Mazzuca and Toshi
Kani.- Assorted power management updates
The "runtime idle" helper routine is changed to take the return
values of the callbacks executed by it into account and to call
rpm_suspend() if they return 0, which allows us to reduce the
overall code bloat a bit (by dropping some code that's not
necessary any more after that modification).The runtime PM documentation is updated by Alan Stern (to reflect
the "runtime idle" behavior change).New trace points for PM QoS are added by Sahara
().PM QoS documentation is updated by Lan Tianyu.
Code cleanups are made and minor issues are addressed by Bernie
Thompson, Bjorn Helgaas, Julius Werner, and Shuah Khan.- devfreq updates
New driver for the Exynos5-bus device from Abhilash Kesavan.
Minor cleanups, fixes and MAINTAINERS update from MyungJoo Ham,
Abhilash Kesavan, Paul Bolle, Rajagopal Venkat, and Wei Yongjun.- OMAP power management updates
Adaptive Voltage Scaling (AVS) SmartReflex voltage control driver
updates from Andrii Tseglytskyi and Nishanth Menon."* tag 'pm+acpi-3.11-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm: (162 commits)
cpufreq: Fix cpufreq regression after suspend/resume
ACPI / PM: Fix possible NULL pointer deref in acpi_pm_device_sleep_state()
PM / Sleep: Warn about system time after resume with pm_trace
cpufreq: don't leave stale policy pointer in cdbs->cur_policy
acpi-cpufreq: Add new sysfs attribute freqdomain_cpus
cpufreq: make sure frequency transitions are serialized
ACPI: implement acpi_os_get_timer() according the spec
ACPI / EC: Add HP Folio 13 to ec_dmi_table in order to skip DSDT scan
ACPI: Add CMOS RTC Operation Region handler support
ACPI / processor: Drop unused variable from processor_perflib.c
cpufreq: tegra: call CPUFREQ_POSTCHANGE notfier in error cases
cpufreq: s3c64xx: call CPUFREQ_POSTCHANGE notfier in error cases
cpufreq: omap: call CPUFREQ_POSTCHANGE notfier in error cases
cpufreq: imx6q: call CPUFREQ_POSTCHANGE notfier in error cases
cpufreq: exynos: call CPUFREQ_POSTCHANGE notfier in error cases
cpufreq: dbx500: call CPUFREQ_POSTCHANGE notfier in error cases
cpufreq: davinci: call CPUFREQ_POSTCHANGE notfier in error cases
cpufreq: arm-big-little: call CPUFREQ_POSTCHANGE notfier in error cases
cpufreq: powernow-k8: call CPUFREQ_POSTCHANGE notfier in error cases
cpufreq: pcc: call CPUFREQ_POSTCHANGE notfier in error cases
...
24 Jun, 2013
1 commit
-
Like other ARM specific drivers, this one requires ARM_CPU_SUSPEND,
as shown by this linker error:drivers/built-in.o: In function `calxeda_pwrdown_idle':
drivers/cpuidle/cpuidle-calxeda.c:84: undefined reference to `cpu_suspend'
drivers/cpuidle/cpuidle-calxeda.c:86: undefined reference to `cpu_resume'Signed-off-by: Arnd Bergmann
Acked-by: Rafael J. Wysocki
Acked-by: Rob Herring
Acked-by: Daniel Lezcano
Cc: linux-pm@vger.kernel.org
11 Jun, 2013
1 commit
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Before commit d6f346f (cpuidle: improve governor Kconfig options),
the CONFIG_ARCH_NEEDS_CPU_IDLE_COUPLED option didn't depend on
CONFIG_CPU_IDLE but now it has been moved under the CPU_IDLE
menuconfig.That raises the following warnings:
warning: (ARCH_OMAP4 && ARCH_TEGRA_2x_SOC) selects ARCH_NEEDS_CPU_IDLE_COUPLED
which has unmet direct dependencies (CPU_IDLE)
warning: (ARCH_OMAP4 && ARCH_TEGRA_2x_SOC) selects ARCH_NEEDS_CPU_IDLE_COUPLED
which has unmet direct dependencies (CPU_IDLE)because the tegra2 and omap4 Kconfig files select this option
without checking if CPU_IDLE is set.Fix that by moving ARCH_NEEDS_CPU_IDLE_COUPLED outside of CPU_IDLE.
[rjw: Changelog]
Signed-off-by: Daniel Lezcano
Signed-off-by: Rafael J. Wysocki
05 Jun, 2013
1 commit
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Add cpuidle support for Xilinx Zynq.
Signed-off-by: Michal Simek
Acked-by: Daniel Lezcano
Signed-off-by: Rafael J. Wysocki
04 Jun, 2013
1 commit
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Each governor is suitable for different kernel configurations: the menu
governor suits better for a tickless system, while the ladder governor fits
better for a periodic timer tick system.The Kconfig does not allow to [un]select a governor, thus both are compiled in
the kernel but the init order makes the menu governor to be the last one to be
registered, so becoming the default. The only way to switch back to the ladder
governor is to enable the sysfs governor switch in the kernel command line.Because it seems nobody complained about this, the menu governor is used by
default most of the time on the system, having both governors is not really
necessary on a tickless system but there isn't a config option to disable one
or another governor.Create a submenu for cpuidle and add a label for each governor, so we can see
the option in the menu config and enable/disable it.The governors will be enabled depending on the CONFIG_NO_HZ option:
- If CONFIG_NO_HZ is set, then the menu governor is selected and the ladder
governor is optional, defaulting to 'yes'
- If CONFIG_NO_HZ is not set, then the ladder governor is selected and the
menu governor is optional, defaulting to 'yes'Signed-off-by: Daniel Lezcano
Signed-off-by: Rafael J. Wysocki
01 Apr, 2013
1 commit
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When the CPU_IDLE and the ARCH_KIRKWOOD options are set it is
pointless to define a new option CPU_IDLE_KIRKWOOD because it
is redundant.The Makefile drivers directory contains a condition to compile
the cpuidle drivers:obj-$(CONFIG_CPU_IDLE) += cpuidle/
Hence, if CPU_IDLE is not set we won't enter this directory.
This patch removes the useless Kconfig option and replaces the
condition in the Makefile by CONFIG_ARCH_KIRKWOOD.Signed-off-by: Daniel Lezcano
Acked-by: Jason Cooper
Signed-off-by: Rafael J. Wysocki
01 Feb, 2013
1 commit
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Move the Kirkwood cpuidle driver out of arch/arm/mach-kirkwood and
into drivers/cpuidle. Convert the driver into a platform driver.Signed-off-by: Andrew Lunn
Signed-off-by: Jason Cooper
13 Dec, 2012
1 commit
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Pull ARM SoC updates from Olof Johansson:
"This contains the bulk of new SoC development for this merge window.Two new platforms have been added, the sunxi platforms (Allwinner A1x
SoCs) by Maxime Ripard, and a generic Broadcom platform for a new
series of ARMv7 platforms from them, where the hope is that we can
keep the platform code generic enough to have them all share one mach
directory. The new Broadcom platform is contributed by Christian
Daudt.Highbank has grown support for Calxeda's next generation of hardware,
ECX-2000.clps711x has seen a lot of cleanup from Alexander Shiyan, and he's
also taken on maintainership of the platform.Beyond this there has been a bunch of work from a number of people on
converting more platforms to IRQ domains, pinctrl conversion, cleanup
and general feature enablement across most of the active platforms."Fix up trivial conflicts as per Olof.
* tag 'soc' of git://git.kernel.org/pub/scm/linux/kernel/git/arm/arm-soc: (174 commits)
mfd: vexpress-sysreg: Remove LEDs code
irqchip: irq-sunxi: Add terminating entry for sunxi_irq_dt_ids
clocksource: sunxi_timer: Add terminating entry for sunxi_timer_dt_ids
irq: versatile: delete dangling variable
ARM: sunxi: add missing include for mdelay()
ARM: EXYNOS: Avoid early use of of_machine_is_compatible()
ARM: dts: add node for PL330 MDMA1 controller for exynos4
ARM: EXYNOS: Add support for secondary CPU bring-up on Exynos4412
ARM: EXYNOS: add UART3 to DEBUG_LL ports
ARM: S3C24XX: Add clkdev entry for camif-upll clock
ARM: SAMSUNG: Add s3c24xx/s3c64xx CAMIF GPIO setup helpers
ARM: sunxi: Add missing sun4i.dtsi file
pinctrl: samsung: Do not initialise statics to 0
ARM i.MX6: remove gate_mask from pllv3
ARM i.MX6: Fix ethernet PLL clocks
ARM i.MX6: rename PLLs according to datasheet
ARM i.MX6: Add pwm support
ARM i.MX51: Add pwm support
ARM i.MX53: Add pwm support
ARM: mx5: Replace clk_register_clkdev with clock DT lookup
...
15 Nov, 2012
1 commit
-
With the tegra3 and the big.LITTLE [1] new architectures, several cpus
with different characteristics (latencies and states) can co-exists on the
system.The cpuidle framework has the limitation of handling only identical cpus.
This patch removes this limitation by introducing the multiple driver support
for cpuidle.This option is configurable at compile time and should be enabled for the
architectures mentioned above. So there is no impact for the other platforms
if the option is disabled. The option defaults to 'n'. Note the multiple drivers
support is also compatible with the existing drivers, even if just one driver is
needed, all the cpu will be tied to this driver using an extra small chunk of
processor memory.The multiple driver support use a per-cpu driver pointer instead of a global
variable and the accessor to this variable are done from a cpu context.In order to keep the compatibility with the existing drivers, the function
'cpuidle_register_driver' and 'cpuidle_unregister_driver' will register
the specified driver for all the cpus.The semantic for the output of /sys/devices/system/cpu/cpuidle/current_driver
remains the same except the driver name will be related to the current cpu.The /sys/devices/system/cpu/cpu[0-9]/cpuidle/driver/name files are added
allowing to read the per cpu driver name.[1] http://lwn.net/Articles/481055/
Signed-off-by: Daniel Lezcano
Acked-by: Peter De Schrijver
Signed-off-by: Rafael J. Wysocki
08 Nov, 2012
1 commit
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Add support for core powergating on Calxeda platforms. Initially, this
supports ECX-1000 (highbank), but support will be added for ECX-2000
later.Signed-off-by: Rob Herring
Cc: Len Brown
Cc: "Rafael J. Wysocki"
02 Jun, 2012
1 commit
-
On some ARM SMP SoCs (OMAP4460, Tegra 2, and probably more), the
cpus cannot be independently powered down, either due to
sequencing restrictions (on Tegra 2, cpu 0 must be the last to
power down), or due to HW bugs (on OMAP4460, a cpu powering up
will corrupt the gic state unless the other cpu runs a work
around). Each cpu has a power state that it can enter without
coordinating with the other cpu (usually Wait For Interrupt, or
WFI), and one or more "coupled" power states that affect blocks
shared between the cpus (L2 cache, interrupt controller, and
sometimes the whole SoC). Entering a coupled power state must
be tightly controlled on both cpus.The easiest solution to implementing coupled cpu power states is
to hotplug all but one cpu whenever possible, usually using a
cpufreq governor that looks at cpu load to determine when to
enable the secondary cpus. This causes problems, as hotplug is an
expensive operation, so the number of hotplug transitions must be
minimized, leading to very slow response to loads, often on the
order of seconds.This file implements an alternative solution, where each cpu will
wait in the WFI state until all cpus are ready to enter a coupled
state, at which point the coupled state function will be called
on all cpus at approximately the same time.Once all cpus are ready to enter idle, they are woken by an smp
cross call. At this point, there is a chance that one of the
cpus will find work to do, and choose not to enter idle. A
final pass is needed to guarantee that all cpus will call the
power state enter function at the same time. During this pass,
each cpu will increment the ready counter, and continue once the
ready counter matches the number of online coupled cpus. If any
cpu exits idle, the other cpus will decrement their counter and
retry.To use coupled cpuidle states, a cpuidle driver must:
Set struct cpuidle_device.coupled_cpus to the mask of all
coupled cpus, usually the same as cpu_possible_mask if all cpus
are part of the same cluster. The coupled_cpus mask must be
set in the struct cpuidle_device for each cpu.Set struct cpuidle_device.safe_state to a state that is not a
coupled state. This is usually WFI.Set CPUIDLE_FLAG_COUPLED in struct cpuidle_state.flags for each
state that affects multiple cpus.Provide a struct cpuidle_state.enter function for each state
that affects multiple cpus. This function is guaranteed to be
called on all cpus at approximately the same time. The driver
should ensure that the cpus all abort together if any cpu tries
to abort once the function is called.update1:
cpuidle: coupled: fix count of online cpus
online_count was never incremented on boot, and was also counting
cpus that were not part of the coupled set. Fix both issues by
introducting a new function that counts online coupled cpus, and
call it from register as well as the hotplug notifier.update2:
cpuidle: coupled: fix decrementing ready count
cpuidle_coupled_set_not_ready sometimes refuses to decrement the
ready count in order to prevent a race condition. This makes it
unsuitable for use when finished with idle. Add a new function
cpuidle_coupled_set_done that decrements both the ready count and
waiting count, and call it after idle is complete.Cc: Amit Kucheria
Cc: Arjan van de Ven
Cc: Trinabh Gupta
Cc: Deepthi Dharwar
Reviewed-by: Santosh Shilimkar
Tested-by: Santosh Shilimkar
Reviewed-by: Kevin Hilman
Tested-by: Kevin Hilman
Signed-off-by: Colin Cross
Acked-by: Rafael J. Wysocki
Signed-off-by: Len Brown
22 Feb, 2012
1 commit
-
We moved all our pSeries idle loops to the cpu idle framework
so we really want it to come up by default.Signed-off-by: Benjamin Herrenschmidt
20 Nov, 2007
1 commit
-
In Linux-2.6.24, CPU_IDLE went upstream, default =n.
For Linux-2.6.25, enable it by default on ACPI systems.
For Linux-2.6.26, we plan to enable it always on ACPI systems.Signed-off-by: Len Brown
10 Oct, 2007
1 commit
-
commit e5a16b1f9eec0af7cfa0830304b41c1c0833cf9f
Author: Len Brown
Date: Tue Oct 2 23:44:44 2007 -0400cpuidle: shrink diff
processor_idle.c | 440 +++++++++++++++++++++++++++++++++++++++++--
1 file changed, 429 insertions(+), 11 deletions(-)Signed-off-by: Len Brown
commit dfbb9d5aedfb18848a3e0d6f6e3e4969febb209c
Author: Len Brown
Date: Wed Sep 26 02:17:55 2007 -0400cpuidle: reduce diff size
Reduces the cpuidle processor_idle.c diff vs 2.6.22 from this
processor_idle.c | 2006 ++++++++++++++++++++++++++-----------------
1 file changed, 1219 insertions(+), 787 deletions(-)to this:
processor_idle.c | 502 +++++++++++++++++++++++++++++++++++++++----
1 file changed, 458 insertions(+), 44 deletions(-)...for the purpose of making the cpuilde patch less invasive
and easier to review.no functional changes. build tested only.
Signed-off-by: Len Brown
commit 889172fc915f5a7fe20f35b133cbd205ce69bf6c
Author: Venki Pallipadi
Date: Thu Sep 13 13:40:05 2007 -0700cpuidle: Retain old ACPI policy for !CONFIG_CPU_IDLE
Retain the old policy in processor_idle, so that when CPU_IDLE is not
configured, old C-state policy will still be used. This provides a
clean gradual migration path from old ACPI policy to new cpuidle
based policy.Signed-off-by: Venkatesh Pallipadi
Signed-off-by: Len Browncommit 9544a8181edc7ecc33b3bfd69271571f98ed08bc
Author: Venki Pallipadi
Date: Thu Sep 13 13:39:17 2007 -0700cpuidle: Configure governors by default
Quoting Len "Do not give an option to users to shoot themselves in the foot".
Remove the configurability of ladder and menu governors as they are
needed for default policy of cpuidle. That way users will not be able to
have cpuidle without any policy loosing all C-state power savings.Signed-off-by: Venkatesh Pallipadi
Signed-off-by: Len Browncommit 8975059a2c1e56cfe83d1bcf031bcf4cb39be743
Author: Adam Belay
Date: Tue Aug 21 18:27:07 2007 -0400CPUIDLE: load ACPI properly when CPUIDLE is disabled
Change the registration return codes for when CPUIDLE
support is not compiled into the kernel. As a result, the ACPI
processor driver will load properly even if CPUIDLE is unavailable.
However, it may be possible to cleanup the ACPI processor driver further
and eliminate some dead code paths.Signed-off-by: Adam Belay
Acked-by: Venkatesh Pallipadi
Signed-off-by: Len Browncommit e0322e2b58dd1b12ec669bf84693efe0dc2414a8
Author: Adam Belay
Date: Tue Aug 21 18:26:06 2007 -0400CPUIDLE: remove cpuidle_get_bm_activity()
Remove cpuidle_get_bm_activity() and updates governors
accordingly.Signed-off-by: Adam Belay
Acked-by: Venkatesh Pallipadi
Signed-off-by: Len Browncommit 18a6e770d5c82ba26653e53d240caa617e09e9ab
Author: Adam Belay
Date: Tue Aug 21 18:25:58 2007 -0400CPUIDLE: max_cstate fix
Currently max_cstate is limited to 0, resulting in no idle processor
power management on ACPI platforms. This patch restores the value to
the array size.Signed-off-by: Adam Belay
Acked-by: Venkatesh Pallipadi
Signed-off-by: Len Browncommit 1fdc0887286179b40ce24bcdbde663172e205ef0
Author: Adam Belay
Date: Tue Aug 21 18:25:40 2007 -0400CPUIDLE: handle BM detection inside the ACPI Processor driver
Update the ACPI processor driver to detect BM activity and
limit state entry depth internally, rather than exposing such
requirements to CPUIDLE. As a result, CPUIDLE can drop this
ACPI-specific interface and become more platform independent. BM
activity is now handled much more aggressively than it was in the
original implementation, so some testing coverage may be needed to
verify that this doesn't introduce any DMA buffer under-run issues.Signed-off-by: Adam Belay
Acked-by: Venkatesh Pallipadi
Signed-off-by: Len Browncommit 0ef38840db666f48e3cdd2b769da676c57228dd9
Author: Adam Belay
Date: Tue Aug 21 18:25:14 2007 -0400CPUIDLE: menu governor updates
Tweak the menu governor to more effectively handle non-timer
break events. Non-timer break events are detected by comparing the
actual sleep time to the expected sleep time. In future revisions, it
may be more reliable to use the timer data structures directly.Signed-off-by: Adam Belay
Acked-by: Venkatesh Pallipadi
Signed-off-by: Len Browncommit bb4d74fca63fa96cf3ace644b15ae0f12b7df5a1
Author: Adam Belay
Date: Tue Aug 21 18:24:40 2007 -0400CPUIDLE: fix 'current_governor' sysfs entry
Allow the "current_governor" sysfs entry to properly handle
input terminated with '\n'.Signed-off-by: Adam Belay
Acked-by: Venkatesh Pallipadi
Signed-off-by: Len Browncommit df3c71559bb69b125f1a48971bf0d17f78bbdf47
Author: Len Brown
Date: Sun Aug 12 02:00:45 2007 -0400cpuidle: fix IA64 build (again)
Signed-off-by: Len Brown
commit a02064579e3f9530fd31baae16b1fc46b5a7bca8
Author: Venkatesh Pallipadi
Date: Sun Aug 12 01:39:27 2007 -0400cpuidle: Remove support for runtime changing of max_cstate
Remove support for runtime changeability of max_cstate. Drivers can use
use latency APIs.max_cstate can still be used as a boot time option and dmi override.
Signed-off-by: Venkatesh Pallipadi
Signed-off-by: Len Browncommit 0912a44b13adf22f5e3f607d263aed23b4910d7e
Author: Venkatesh Pallipadi
Date: Sun Aug 12 01:39:16 2007 -0400cpuidle: Remove ACPI cstate_limit calls from ipw2100
ipw2100 already has code to use accetable_latency interfaces to limit the
C-state. Remove the calls to acpi_set_cstate_limit and acpi_get_cstate_limit
as they are redundant.Signed-off-by: Venkatesh Pallipadi
Signed-off-by: Len Browncommit c649a76e76be6bff1fd770d0a775798813a3f6e0
Author: Venkatesh Pallipadi
Date: Sun Aug 12 01:35:39 2007 -0400cpuidle: compile fix for pause and resume functions
Fix the compilation failure when cpuidle is not compiled in.
Signed-off-by: Venkatesh Pallipadi
Acked-by: Adam Belay
Signed-off-by: Len Browncommit 2305a5920fb8ee6ccec1c62ade05aa8351091d71
Author: Adam Belay
Date: Thu Jul 19 00:49:00 2007 -0400cpuidle: re-write
Some portions have been rewritten to make the code cleaner and lighter
weight. The following is a list of changes:1.) the state name is now included in the sysfs interface
2.) detection, hotplug, and available state modifications are handled by
CPUIDLE drivers directly
3.) the CPUIDLE idle handler is only ever installed when at least one
cpuidle_device is enabled and ready
4.) the menu governor BM code no longer overflows
5.) the sysfs attributes are now printed as unsigned integers, avoiding
negative values
6.) a variety of other small cleanupsAlso, Idle drivers are no longer swappable during runtime through the
CPUIDLE sysfs inteface. On i386 and x86_64 most idle handlers (e.g.
poll, mwait, halt, etc.) don't benefit from an infrastructure that
supports multiple states, so I think using a more general case idle
handler selection mechanism would be cleaner.Signed-off-by: Adam Belay
Acked-by: Venkatesh Pallipadi
Acked-by: Shaohua Li
Signed-off-by: Len Browncommit df25b6b56955714e6e24b574d88d1fd11f0c3ee5
Author: Len Brown
Date: Tue Jul 24 17:08:21 2007 -0400cpuidle: fix IA64 buid
Signed-off-by: Len Brown
commit fd6ada4c14488755ff7068860078c437431fbccd
Author: Adrian Bunk
Date: Mon Jul 9 11:33:13 2007 -0700cpuidle: static
make cpuidle_replace_governor() static
Signed-off-by: Adrian Bunk
Cc: Venkatesh Pallipadi
Signed-off-by: Andrew Morton
Signed-off-by: Len Browncommit c1d4a2cebcadf2429c0c72e1d29aa2a9684c32e0
Author: Adrian Bunk
Date: Tue Jul 3 00:54:40 2007 -0400cpuidle: static
This patch makes the needlessly global struct menu_governor static.
Signed-off-by: Adrian Bunk
Signed-off-by: Andrew Morton
Signed-off-by: Len Browncommit dbf8780c6e8d572c2c273da97ed1cca7608fd999
Author: Andrew Morton
Date: Tue Jul 3 00:49:14 2007 -0400export symbol tick_nohz_get_sleep_length
ERROR: "tick_nohz_get_sleep_length" [drivers/cpuidle/governors/menu.ko] undefined!
ERROR: "tick_nohz_get_idle_jiffies" [drivers/cpuidle/governors/menu.ko] undefined!And please be sure to get your changes to core kernel suitably reviewed.
Cc: Adam Belay
Cc: Venki Pallipadi
Cc: Ingo Molnar
Cc: Thomas Gleixner
Cc: john stultz
Signed-off-by: Andrew Morton
Signed-off-by: Len Browncommit 29f0e248e7017be15f99febf9143a2cef00b2961
Author: Andrew Morton
Date: Tue Jul 3 00:43:04 2007 -0400tick.h needs hrtimer.h
It uses hrtimers.
Signed-off-by: Andrew Morton
Signed-off-by: Len Browncommit e40cede7d63a029e92712a3fe02faee60cc38fb4
Author: Venki Pallipadi
Date: Tue Jul 3 00:40:34 2007 -0400cpuidle: first round of documentation updates
Documentation changes based on Pavel's feedback.
Signed-off-by: Venkatesh Pallipadi
Signed-off-by: Andrew Morton
Signed-off-by: Len Browncommit 83b42be2efece386976507555c29e7773a0dfcd1
Author: Venki Pallipadi
Date: Tue Jul 3 00:39:25 2007 -0400cpuidle: add rating to the governors and pick the one with highest rating by default
Introduce a governor rating scheme to pick the right governor by default.
Signed-off-by: Venkatesh Pallipadi
Signed-off-by: Andrew Morton
Signed-off-by: Len Browncommit d2a74b8c5e8f22def4709330d4bfc4a29209b71c
Author: Venki Pallipadi
Date: Tue Jul 3 00:38:08 2007 -0400cpuidle: make cpuidle sysfs driver governor switch off by default
Make default cpuidle sysfs to show current_governor and current_driver in
read-only mode. More elaborate available_governors and available_drivers with
writeable current_governor and current_driver interface only appear with
"cpuidle_sysfs_switch" boot parameter.Signed-off-by: Venkatesh Pallipadi
Signed-off-by: Andrew Morton
Signed-off-by: Len Browncommit 1f60a0e80bf83cf6b55c8845bbe5596ed8f6307b
Author: Venki Pallipadi
Date: Tue Jul 3 00:37:00 2007 -0400cpuidle: menu governor: change the early break condition
Change the C-state early break out algorithm in menu governor.
We only look at early breakouts that result in wakeups shorter than idle
state's target_residency. If such a breakout is frequent enough, eliminate
the particular idle state upto a timeout period.Signed-off-by: Venkatesh Pallipadi
Signed-off-by: Andrew Morton
Signed-off-by: Len Browncommit 45a42095cf64b003b4a69be3ce7f434f97d7af51
Author: Venki Pallipadi
Date: Tue Jul 3 00:35:38 2007 -0400cpuidle: fix uninitialized variable in sysfs routine
Fix the uninitialized usage of ret.
Signed-off-by: Venkatesh Pallipadi
Signed-off-by: Andrew Morton
Signed-off-by: Len Browncommit 80dca7cdba3e6ee13eae277660873ab9584eb3be
Author: Venki Pallipadi
Date: Tue Jul 3 00:34:16 2007 -0400cpuidle: reenable /proc/acpi//power interface for the time being
Keep /proc/acpi/processor/CPU*/power around for a while as powertop depends
on it. It will be marked deprecated and removed in future. powertop can use
cpuidle interfaces instead.Signed-off-by: Venkatesh Pallipadi
Signed-off-by: Andrew Morton
Signed-off-by: Len Browncommit 589c37c2646c5e3813a51255a5ee1159cb4c33fc
Author: Venki Pallipadi
Date: Tue Jul 3 00:32:37 2007 -0400cpuidle: menu governor and hrtimer compile fix
Compile fix for menu governor.
Signed-off-by: Venkatesh Pallipadi
Signed-off-by: Andrew Morton
Signed-off-by: Len Browncommit 0ba80bd9ab3ed304cb4f19b722e4cc6740588b5e
Author: Len Brown
Date: Thu May 31 22:51:43 2007 -0400cpuidle: build fix - cpuidle vs ipw2100 module
ERROR: "acpi_set_cstate_limit" [drivers/net/wireless/ipw2100.ko] undefined!
Signed-off-by: Len Brown
commit d7d8fa7f96a7f7682be7c6cc0cc53fa7a18c3b58
Author: Adam Belay
Date: Sat Mar 24 03:47:07 2007 -0400cpuidle: add the 'menu' governor
Here is my first take at implementing an idle PM governor that takes
full advantage of NO_HZ. I call it the 'menu' governor because it
considers the full list of idle states before each entry.I've kept the implementation fairly simple. It attempts to guess the
next residency time and then chooses a state that would meet at least
the break-even point between power savings and entry cost. To this end,
it selects the deepest idle state that satisfies the following
constraints:
1. If the idle time elapsed since bus master activity was detected
is below a threshold (currently 20 ms), then limit the selection
to C2-type or above.
2. Do not choose a state with a break-even residency that exceeds
the expected time remaining until the next timer interrupt.
3. Do not choose a state with a break-even residency that exceeds
the elapsed time between the last pair of break events,
excluding timer interrupts.This governor has an advantage over "ladder" governor because it
proactively checks how much time remains until the next timer interrupt
using the tick infrastructure. Also, it handles device interrupt
activity more intelligently by not including timer interrupts in break
event calculations. Finally, it doesn't make policy decisions using the
number of state entries, which can have variable residency times (NO_HZ
makes these potentially very large), and instead only considers sleep
time deltas.The menu governor can be selected during runtime using the cpuidle sysfs
interface like so:
"echo "menu" > /sys/devices/system/cpu/cpuidle/current_governor"Signed-off-by: Adam Belay
Signed-off-by: Len Browncommit a4bec7e65aa3b7488b879d971651cc99a6c410fe
Author: Adam Belay
Date: Sat Mar 24 03:47:03 2007 -0400cpuidle: export time until next timer interrupt using NO_HZ
Expose information about the time remaining until the next
timer interrupt expires by utilizing the dynticks infrastructure.
Also modify the main idle loop to allow dynticks to handle
non-interrupt break events (e.g. DMA). Finally, expose sleep ticks
information to external code. Thomas Gleixner is responsible for much
of the code in this patch. However, I've made some additional changes,
so I'm probably responsible if there are any bugs or oversights :)Signed-off-by: Adam Belay
Signed-off-by: Len Browncommit 2929d8996fbc77f41a5ff86bb67cdde3ca7d2d72
Author: Adam Belay
Date: Sat Mar 24 03:46:58 2007 -0400cpuidle: governor API changes
This patch prepares cpuidle for the menu governor. It adds an optional
stage after idle state entry to give the governor an opportunity to
check why the state was exited. Also it makes sure the idle loop
returns after each state entry, allowing the appropriate dynticks code
to run.Signed-off-by: Adam Belay
Signed-off-by: Len Browncommit 3a7fd42f9825c3b03e364ca59baa751bb350775f
Author: Venki Pallipadi
Date: Thu Apr 26 00:03:59 2007 -0700cpuidle: hang fix
Prevent hang on x86-64, when ACPI processor driver is added as a module on
a system that does not support C-states.x86-64 expects all idle handlers to enable interrupts before returning from
idle handler. This is due to enter_idle(), exit_idle() races. Make
cpuidle_idle_call() confirm to this when there is no pm_idle_old.Also, cpuidle look at the return values of attch_driver() and set
current_driver to NULL if attach fails on all CPUs.Signed-off-by: Venkatesh Pallipadi
Signed-off-by: Andrew Morton
Signed-off-by: Len Browncommit 4893339a142afbd5b7c01ffadfd53d14746e858e
Author: Shaohua Li
Date: Thu Apr 26 10:40:09 2007 +0800cpuidle: add support for max_cstate limit
With CPUIDLE framework, the max_cstate (to limit max cpu c-state)
parameter is ingored. Some systems require it to ignore C2/C3
and some drivers like ipw require it too.Signed-off-by: Shaohua Li
Signed-off-by: Len Browncommit 43bbbbe1cb998cbd2df656f55bb3bfe30f30e7d1
Author: Shaohua Li
Date: Thu Apr 26 10:40:13 2007 +0800cpuidle: add cpuidle_fore_redetect_devices API
add cpuidle_force_redetect_devices API,
which forces all CPU redetect idle states.
Next patch will use it.Signed-off-by: Shaohua Li
Signed-off-by: Len Browncommit d1edadd608f24836def5ec483d2edccfb37b1d19
Author: Shaohua Li
Date: Thu Apr 26 10:40:01 2007 +0800cpuidle: fix sysfs related issue
Fix the cpuidle sysfs issue.
a. make kobject dynamicaly allocated
b. fixed sysfs init issue to avoid suspend/resume issueSigned-off-by: Shaohua Li
Signed-off-by: Len Browncommit 7169a5cc0d67b263978859672e86c13c23a5570d
Author: Randy Dunlap
Date: Wed Mar 28 22:52:53 2007 -0400cpuidle: 1-bit field must be unsigned
A 1-bit bitfield has no room for a sign bit.
drivers/cpuidle/governors/ladder.c:54:16: error: dubious bitfield without explicit `signed' or `unsigned'Signed-off-by: Randy Dunlap
Cc: Venkatesh Pallipadi
Signed-off-by: Andrew Morton
Signed-off-by: Len Browncommit 4658620158dc2fbd9e4bcb213c5b6fb5d05ba7d4
Author: Venkatesh Pallipadi
Date: Wed Mar 28 22:52:41 2007 -0400cpuidle: fix boot hang
Patch for cpuidle boot hang reported by Larry Finger here.
http://www.ussg.iu.edu/hypermail/linux/kernel/0703.2/2025.htmlSigned-off-by: Venkatesh Pallipadi
Cc: Larry Finger
Signed-off-by: Andrew Morton
Signed-off-by: Len Browncommit c17e168aa6e5fe3851baaae8df2fbc1cf11443a9
Author: Len Brown
Date: Wed Mar 7 04:37:53 2007 -0500cpuidle: ladder does not depend on ACPI
build fix for CONFIG_ACPI=n
In file included from drivers/cpuidle/governors/ladder.c:21:
include/acpi/processor.h:88: error: expected specifier-qualifier-list before âacpi_integerâ
include/acpi/processor.h:106: error: expected specifier-qualifier-list before âacpi_integerâ
include/acpi/processor.h:168: error: expected specifier-qualifier-list before âacpi_handleâSigned-off-by: Len Brown
commit 8c91d958246bde68db0c3f0c57b535962ce861cb
Author: Adrian Bunk
Date: Tue Mar 6 02:29:40 2007 -0800cpuidle: make code static
This patch makes the following needlessly global code static:
- driver.c: __cpuidle_find_driver()
- governor.c: __cpuidle_find_governor()
- ladder.c: struct ladder_governorSigned-off-by: Adrian Bunk
Cc: Venkatesh Pallipadi
Cc: Adam Belay
Cc: Shaohua Li
Signed-off-by: Andrew Morton
Signed-off-by: Len Browncommit 0c39dc3187094c72c33ab65a64d2017b21f372d2
Author: Venkatesh Pallipadi
Date: Wed Mar 7 02:38:22 2007 -0500cpu_idle: fix build break
This patch fixes a build breakage with !CONFIG_HOTPLUG_CPU and
CONFIG_CPU_IDLE.Signed-off-by: Venkatesh Pallipadi
Signed-off-by: Adrian Bunk
Signed-off-by: Andrew Morton
Signed-off-by: Len Browncommit 8112e3b115659b07df340ef170515799c0105f82
Author: Venkatesh Pallipadi
Date: Tue Mar 6 02:29:39 2007 -0800cpuidle: build fix for !CPU_IDLE
Fix the compile issues when CPU_IDLE is not configured.
Signed-off-by: Venkatesh Pallipadi
Cc: Adam Belay
Cc: Shaohua Li
Signed-off-by: Andrew Morton
Signed-off-by: Len Browncommit 1eb4431e9599cd25e0d9872f3c2c8986821839dd
Author: Venkatesh Pallipadi
Date: Thu Feb 22 13:54:57 2007 -0800cpuidle take2: Basic documentation for cpuidle
Documentation for cpuidle infrastructure
Signed-off-by: Venkatesh Pallipadi
Signed-off-by: Adam Belay
Signed-off-by: Shaohua Li
Signed-off-by: Len Browncommit ef5f15a8b79123a047285ec2e3899108661df779
Author: Venkatesh Pallipadi
Date: Thu Feb 22 13:54:03 2007 -0800cpuidle take2: Hookup ACPI C-states driver with cpuidle
Hookup ACPI C-states onto generic cpuidle infrastructure.
drivers/acpi/procesor_idle.c is now a ACPI C-states driver that registers as
a driver in cpuidle infrastructure and the policy part is removed from
drivers/acpi/processor_idle.c. We use governor in cpuidle instead.Signed-off-by: Shaohua Li
Signed-off-by: Venkatesh Pallipadi
Signed-off-by: Adam Belay
Signed-off-by: Len Browncommit 987196fa82d4db52c407e8c9d5dec884ba602183
Author: Venkatesh Pallipadi
Date: Thu Feb 22 13:52:57 2007 -0800cpuidle take2: Core cpuidle infrastructure
Announcing 'cpuidle', a new CPU power management infrastructure to manage
idle CPUs in a clean and efficient manner.
cpuidle separates out the drivers that can provide support for multiple types
of idle states and policy governors that decide on what idle state to use
at run time.
A cpuidle driver can support multiple idle states based on parameters like
varying power consumption, wakeup latency, etc (ACPI C-states for example).
A cpuidle governor can be usage model specific (laptop, server,
laptop on battery etc).
Main advantage of the infrastructure being, it allows independent development
of drivers and governors and allows for better CPU power management.A huge thanks to Adam Belay and Shaohua Li who were part of this mini-project
since its beginning and are greatly responsible for this patchset.This patch:
Core cpuidle infrastructure.
Introduces a new abstraction layer for cpuidle:
* which manages drivers that can support multiple idles states. Drivers
can be generic or particular to specific hardware/platform
* allows pluging in multiple policy governors that can take idle state policy
decision
* The core also has a set of sysfs interfaces with which administrato can know
about supported drivers and governors and switch them at run time.Signed-off-by: Adam Belay
Signed-off-by: Shaohua Li
Signed-off-by: Venkatesh Pallipadi
Signed-off-by: Len BrownSigned-off-by: Len Brown