talos-op-linux/drivers/cpuidle/Kconfig, branch master

cpuidle: Fix Kconfig indentation

2019-11-29T10:47:35+00:00

Adjust indentation from spaces to tab (+optional two spaces) as in coding style with command like: $ sed -e 's/^ /\t/' -i */Kconfig Signed-off-by: Krzysztof Kozlowski Signed-off-by: Rafael J. Wysocki

cpuidle: add haltpoll governor

2019-07-30T15:27:37+00:00

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 cpuidle-haltpoll driver

2019-07-30T15:27:37+00:00

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

treewide: Add SPDX license identifier - Makefile/Kconfig

2019-05-21T08:50:46+00:00

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

cpuidle: New timer events oriented governor for tickless systems

2019-01-16T22:07:30+00:00

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

cpuidle: Don't enable all governors by default

2016-01-15T21:39:58+00:00

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

ARM: cpuidle: Enable the ARM64 driver for both ARM32/ARM64

2015-03-24T09:16:11+00:00

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

drivers: cpuidle: CPU idle ARM64 driver

2014-09-25T08:52:21+00:00

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

drivers: cpuidle: implement DT based idle states infrastructure

2014-09-25T08:52:20+00:00

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

cpuidle: Remove manual selection of the multiple driver support

2014-07-28T23:35:29+00:00

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