linux-dev/drivers/cpuidle/governors/menu.c, branch linus/master

cpuidle: menu: Fix typo in a comment

2021-11-24T16:30:44Z

The word `these' in a comment is repeated, so drop one. Signed-off-by: Jason Wang [ rjw: Changelog edits ] Signed-off-by: Rafael J. Wysocki

sched: Make nr_iowait_cpu() return 32-bit value

2021-05-12T19:34:16Z

Runqueue ->nr_iowait counters are 32-bit anyway. Propagate 32-bitness into other code, but don't try too hard. Signed-off-by: Alexey Dobriyan Signed-off-by: Ingo Molnar Link: https://lore.kernel.org/r/20210422200228.1423391-3-adobriyan@gmail.com

cpuidle: menu: Take negative "sleep length" values into account

2021-04-07T17:26:44Z

Make the menu governor check the tick_nohz_get_next_hrtimer() return value so as to avoid dealing with negative "sleep length" values and make it use that value directly when the tick is stopped. While at it, rename local variable delta_next in menu_select() to delta_tick which better reflects its purpose. Signed-off-by: Rafael J. Wysocki

cpuidle: Use nanoseconds as the unit of time

2019-11-11T20:56:07Z

Currently, the cpuidle subsystem uses microseconds as the unit of time which (among other things) causes the idle loop to incur some integer division overhead for no clear benefit. In order to allow cpuidle to measure time in nanoseconds, add two new fields, exit_latency_ns and target_residency_ns, to represent the exit latency and target residency of an idle state in nanoseconds, respectively, to struct cpuidle_state and initialize them with the help of the corresponding values in microseconds provided by drivers. Additionally, change cpuidle_governor_latency_req() to return the idle state exit latency constraint in nanoseconds. Also meeasure idle state residency (last_residency_ns in struct cpuidle_device and time_ns in struct cpuidle_driver) in nanoseconds and update the cpuidle core and governors accordingly. However, the menu governor still computes typical intervals in microseconds to avoid integer overflows. Signed-off-by: Rafael J. Wysocki Acked-by: Peter Zijlstra (Intel) Acked-by: Doug Smythies Tested-by: Doug Smythies

cpuidle: Consolidate disabled state checks

2019-11-06T12:19:56Z

There are two reasons why CPU idle states may be disabled: either because the driver has disabled them or because they have been disabled by user space via sysfs. In the former case, the state's "disabled" flag is set once during the initialization of the driver and it is never cleared later (it is read-only effectively). In the latter case, the "disable" field of the given state's cpuidle_state_usage struct is set and it may be changed via sysfs. Thus checking whether or not an idle state has been disabled involves reading these two flags every time. In order to avoid the additional check of the state's "disabled" flag (which is effectively read-only anyway), use the value of it at the init time to set a (new) flag in the "disable" field of that state's cpuidle_state_usage structure and use the sysfs interface to manipulate another (new) flag in it. This way the state is disabled whenever the "disable" field of its cpuidle_state_usage structure is nonzero, whatever the reason, and it is the only place to look into to check whether or not the state has been disabled. Signed-off-by: Rafael J. Wysocki Acked-by: Daniel Lezcano Acked-by: Peter Zijlstra (Intel)

cpuidle: menu: Allow tick to be stopped if PM QoS is used

2019-08-05T09:02:44Z

After commit 554c8aa8ecad ("sched: idle: Select idle state before stopping the tick") the menu governor prevents the scheduler tick from being stopped (unless stopped already) if there is a PM QoS latency constraint for the given CPU and the target residency of the deepest idle state matching that constraint is below the tick boundary. However, that is problematic if CPUs with PM QoS latency constraints are idle for long times, because it effectively causes the tick to run on them all the time which is wasteful. [It is also confusing and questionable if they are full dynticks CPUs.] To address that issue, make the menu governor allow the tick to be stopped only if the idle duration predicted by it is beyond the tick boundary, except when the shallowest idle state is selected upfront and it is not a "polling" one. Fixes: 554c8aa8ecad ("sched: idle: Select idle state before stopping the tick") Link: https://lore.kernel.org/lkml/79b247b3-e056-610e-9a07-e685dfdaa6c9@gmail.com/ Reported-by: Thomas Lindroth Tested-by: Thomas Lindroth Signed-off-by: Rafael J. Wysocki

governors: unify last_state_idx

2019-07-30T15:27:37Z

Since this field is shared by all governors, move it to cpuidle device structure. Signed-off-by: Marcelo Tosatti Signed-off-by: Rafael J. Wysocki

treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 215

2019-05-30T18:29:54Z

Based on 1 normalized pattern(s): this code is licenced under the gpl version 2 as described in the copying file that acompanies the linux kernel extracted by the scancode license scanner the SPDX license identifier GPL-2.0-only has been chosen to replace the boilerplate/reference in 1 file(s). Signed-off-by: Thomas Gleixner Reviewed-by: Alexios Zavras Reviewed-by: Allison Randal Reviewed-by: Steve Winslow Cc: linux-spdx@vger.kernel.org Link: https://lkml.kernel.org/r/20190528171439.466585205@linutronix.de Signed-off-by: Greg Kroah-Hartman

cpuidle: menu: Avoid overflows when computing variance

2019-03-07T09:54:22Z

The variance computation in get_typical_interval() may overflow if the square of the value of diff exceeds the maximum for the int64_t data type value which basically is the case when it is of the order of UINT_MAX. However, data points so far in the future don't matter for idle state selection anyway, so change the initial threshold value in get_typical_interval() to INT_MAX which will cause more "outlying" data points to be discarded without affecting the selection result. Reported-by: Randy Dunlap Signed-off-by: Rafael J. Wysocki

Merge tag 'pm-4.20-rc1-2' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm

2018-10-30T16:08:07Z

Pull more power management updates from Rafael Wysocki: "These remove a questionable heuristic from the menu cpuidle governor, fix a recent build regression in the intel_pstate driver, clean up ARM big-Little support in cpufreq and fix up hung task watchdog's interaction with system-wide power management transitions. Specifics: - Fix build regression in the intel_pstate driver that doesn't build without CONFIG_ACPI after recent changes (Dominik Brodowski). - One of the heuristics in the menu cpuidle governor is based on a function returning 0 most of the time, so drop it and clean up the scheduler code related to it (Daniel Lezcano). - Prevent the arm_big_little cpufreq driver from being used on ARM64 which is not suitable for it and drop the arm_big_little_dt driver that is not used any more (Sudeep Holla). - Prevent the hung task watchdog from triggering during resume from system-wide sleep states by disabling it before freezing tasks and enabling it again after they have been thawed (Vitaly Kuznetsov)" * tag 'pm-4.20-rc1-2' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm: kernel: hung_task.c: disable on suspend cpufreq: remove unused arm_big_little_dt driver cpufreq: drop ARM_BIG_LITTLE_CPUFREQ support for ARM64 cpufreq: intel_pstate: Fix compilation for !CONFIG_ACPI cpuidle: menu: Remove get_loadavg() from the performance multiplier sched: Factor out nr_iowait and nr_iowait_cpu