CPU_PM_CPU_IDLE_ENTER_RETENTION skips calling cpu_pm_enter() and
cpu_pm_exit(). By not calling cpu_pm functions in idle entry/exit
paths we can reduce the latency involved in entering and exiting
the low power idle state.
On ARM64 based Qualcomm server platform we measured below overhead
for calling cpu_pm_enter and cpu_pm_exit for retention states.
workload: stress --hdd #CPUs --hdd-bytes 32M -t 30
Average overhead of cpu_pm_enter - 1.2us
Average overhead of cpu_pm_exit - 3.1us
Acked-by: Sudeep Holla <sudeep.holla@arm.com>
Signed-off-by: Prashanth Prakash <pprakash@codeaurora.org>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Commit af391b15f7 ("arm64: kernel: rename __cpu_suspend to keep it
aligned with arm") renamed cpu_suspend() to arm_cpuidle_suspend(), but
forgot to update the kerneldoc header.
Fixes: af391b15f7 ("arm64: kernel: rename __cpu_suspend to keep it aligned with arm")
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Will Deacon <will.deacon@arm.com>
This patch adds appropriate callbacks to support ACPI Low Power Idle
(LPI) on ARM64.
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Acked-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Commit ea389daa7f (arm64: cpuidle: add __init section marker to
arm_cpuidle_init) added the __init annotation to arm_cpuidle_init
as it was not needed after booting which was correct at that time.
However with the introduction of ACPI LPI support, this will be used
from cpuhotplug path in ACPI processor driver.
This patch drops the __init annotation from arm_cpuidle_init to avoid
the following warning:
WARNING: vmlinux.o(.text+0x113c8): Section mismatch in reference from the
function acpi_processor_ffh_lpi_probe() to the function
.init.text:arm_cpuidle_init()
The function acpi_processor_ffh_lpi_probe() references
the function __init arm_cpuidle_init().
This is often because acpi_processor_ffh_lpi_probe() lacks a __init
annotation or the annotation of arm_cpuidle_init is wrong.
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Acked-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Currently, we check two pointers: cpu_ops and cpu_suspend on every idle
state entry. These pointers check can be avoided:
If cpu_ops has not been registered, arm_cpuidle_init() will return
-EOPNOTSUPP, so arm_cpuidle_suspend() will never have chance to
run. In other word, the cpu_ops check can be avoid.
Similarly, the cpu_suspend check could be avoided in this hot path by
moving it into arm_cpuidle_init().
I measured the 4096 * time from arm_cpuidle_suspend entry point to the
cpu_psci_cpu_suspend entry point. HW platform is Marvell BG4CT STB
board.
1. only one shell, no other process, hot-unplug secondary cpus, execute
the following cmd
while true
do
sleep 0.2
done
before the patch: 1581220ns
after the patch: 1579630ns
reduced by 0.1%
2. only one shell, no other process, hot-unplug secondary cpus, execute
the following cmd
while true
do
md5sum /tmp/testfile
sleep 0.2
done
NOTE: the testfile size should be larger than L1+L2 cache size
before the patch: 1961960ns
after the patch: 1912500ns
reduced by 2.5%
So the more complex the system load, the bigger the improvement.
Signed-off-by: Jisheng Zhang <jszhang@marvell.com>
Acked-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
It is not needed after booting, this patch moves the arm_cpuidle_init()
function to the __init section.
Signed-off-by: Jisheng Zhang <jszhang@marvell.com>
Reviewed-by: Krzysztof Kozlowski <k.kozlowski@samsung.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
This patch renames __cpu_suspend to cpu_suspend so that it's aligned
with ARM32. It also removes the redundant wrapper created.
This is in preparation to implement generic PSCI system suspend using
the cpu_{suspend,resume} which now has the same interface on both ARM
and ARM64.
Cc: Mark Rutland <mark.rutland@arm.com>
Reviewed-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Reviewed-by: Ashwin Chaugule <ashwin.chaugule@linaro.org>
Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
ARM64 CPU operations such as cpu_init and cpu_init_idle take
a struct device_node pointer as a parameter, which corresponds to
the device tree node of the logical cpu on which the operation
has to be applied.
With the advent of ACPI on arm64, where MADT static table entries
are used to initialize cpus, the device tree node parameter
in cpu_ops hooks become useless when booting with ACPI, since
in that case cpu device tree nodes are not present and can not be
used for cpu initialization.
The current cpu_init hook requires a struct device_node pointer
parameter because it is called while parsing the device tree to
initialize CPUs, when the cpu_logical_map (that is used to match
a cpu node reg property to a device tree node) for a given logical
cpu id is not set up yet. This means that the cpu_init hook cannot
rely on the of_get_cpu_node function to retrieve the device tree
node corresponding to the logical cpu id passed in as parameter,
so the cpu device tree node must be passed in as a parameter to fix
this catch-22 dependency cycle.
This patch reshuffles the cpu_logical_map initialization code so
that the cpu_init cpu_ops hook can safely use the of_get_cpu_node
function to retrieve the cpu device tree node, removing the need for
the device tree node pointer parameter.
In the process, the patch removes device tree node parameters
from all cpu_ops hooks, in preparation for SMP DT/ACPI cpus
initialization consolidation.
Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Acked-by: Hanjun Guo <hanjun.guo@linaro.org>
Acked-by: Sudeep Holla <sudeep.holla@arm.com>
Acked-by: Mark Rutland <mark.rutland@arm.com>
Tested-by: Hanjun Guo <hanjun.guo@linaro.org>
Tested-by: Mark Rutland <mark.rutland@arm.com> [DT]
Cc: Will Deacon <will.deacon@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
With this change the cpuidle-arm64.c file calls the same function name
for both ARM and ARM64.
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Acked-by: Kevin Hilman <khilman@linaro.org>
Acked-by: Rob Herring <robherring2@gmail.com>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Tested-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
ARM64_CPU_SUSPEND config option was introduced to make code providing
context save/restore selectable only on platforms requiring power
management capabilities.
Currently ARM64_CPU_SUSPEND depends on the PM_SLEEP config option which
in turn is set by the SUSPEND config option.
The introduction of CPU_IDLE for arm64 requires that code configured
by ARM64_CPU_SUSPEND (context save/restore) should be compiled in
in order to enable the CPU idle driver to rely on CPU operations
carrying out context save/restore.
The ARM64_CPUIDLE config option (ARM64 generic idle driver) is therefore
forced to select ARM64_CPU_SUSPEND, even if there may be (ie PM_SLEEP)
failed dependencies, which is not a clean way of handling the kernel
configuration option.
For these reasons, this patch removes the ARM64_CPU_SUSPEND config option
and makes the context save/restore dependent on CPU_PM, which is selected
whenever either SUSPEND or CPU_IDLE are configured, cleaning up dependencies
in the process.
This way, code previously configured through ARM64_CPU_SUSPEND is
compiled in whenever a power management subsystem requires it to be
present in the kernel (SUSPEND || CPU_IDLE), which is the behaviour
expected on ARM64 kernels.
The cpu_suspend and cpu_init_idle CPU operations are added only if
CPU_IDLE is selected, since they are CPU_IDLE specific methods and
should be grouped and defined accordingly.
PSCI CPU operations are updated to reflect the introduced changes.
Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Will Deacon <will.deacon@arm.com>
Cc: Krzysztof Kozlowski <k.kozlowski@samsung.com>
Cc: Daniel Lezcano <daniel.lezcano@linaro.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
The CPUidle subsystem on ARM64 machines requires the idle states
implementation back-end to initialize idle states parameter upon
boot. This patch adds a hook in the CPU operations structure that
should be initialized by the CPU operations back-end in order to
provide a function that initializes cpu idle states.
This patch also adds the infrastructure to arm64 kernel required
to export the CPU operations based initialization interface, so
that drivers (ie CPUidle) can use it when they are initialized
at probe time.
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Prashanth Prakash