Pull ARM SoC driver updates from Arnd Bergmann:
"These are all the driver updates for SoC specific drivers. There are a
couple of subsystems with individual maintainers picking up their
patches here:
- The reset controller subsystem add support for a few new SoC
variants to existing drivers, along with other minor improvements
- The OP-TEE subsystem gets a driver for the ARM FF-A transport
- The memory controller subsystem has improvements for Tegra,
Mediatek, Renesas, Freescale and Broadcom specific drivers.
- The tegra cpuidle driver changes get merged through this tree this
time. There are only minor changes, but they depend on other tegra
driver updates here.
- The ep93xx platform finally moves to using the drivers/clk/
subsystem, moving the code out of arch/arm in the process. This
depends on a small sound driver change that is included here as
well.
- There are some minor updates for Qualcomm and Tegra specific
firmware drivers.
The other driver updates are mainly for drivers/soc, which contains a
mixture of vendor specific drivers that don't really fit elsewhere:
- Mediatek drivers gain more support for MT8192, with new support for
hw-mutex and mmsys routing, plus support for reset lines in the
mmsys driver.
- Qualcomm gains a new "sleep stats" driver, and support for the
"Generic Packet Router" in the APR driver.
- There is a new user interface for routing the UARTS on ASpeed BMCs,
something that apparently nobody else has needed so far.
- More drivers can now be built as loadable modules, in particular
for Broadcom and Samsung platforms.
- Lots of improvements to the TI sysc driver for better
suspend/resume support"
Finally, there are lots of minor cleanups and new device IDs for
amlogic, renesas, tegra, qualcomm, mediateka, samsung, imx,
layerscape, allwinner, broadcom, and omap"
* tag 'drivers-5.16' of git://git.kernel.org/pub/scm/linux/kernel/git/soc/soc: (179 commits)
optee: Fix spelling mistake "reclain" -> "reclaim"
Revert "firmware: qcom: scm: Add support for MC boot address API"
qcom: spm: allow compile-testing
firmware: arm_ffa: Remove unused 'compat_version' variable
soc: samsung: exynos-chipid: add exynosautov9 SoC support
firmware: qcom: scm: Don't break compile test on non-ARM platforms
soc: qcom: smp2p: Add of_node_put() before goto
soc: qcom: apr: Add of_node_put() before return
soc: qcom: qcom_stats: Fix client votes offset
soc: qcom: rpmhpd: fix sm8350_mxc's peer domain
dt-bindings: arm: cpus: Document qcom,msm8916-smp enable-method
ARM: qcom: Add qcom,msm8916-smp enable-method identical to MSM8226
firmware: qcom: scm: Add support for MC boot address API
soc: qcom: spm: Add 8916 SPM register data
dt-bindings: soc: qcom: spm: Document qcom,msm8916-saw2-v3.0-cpu
soc: qcom: socinfo: Add PM8150C and SMB2351 models
firmware: qcom_scm: Fix error retval in __qcom_scm_is_call_available()
soc: aspeed: Add UART routing support
soc: fsl: dpio: rename the enqueue descriptor variable
soc: fsl: dpio: use an explicit NULL instead of 0
...
Qualcomm driver updates for v5.16
This drops the use of power-domains for exposing the load_state from the
QMP driver to clients, to avoid issues related to system suspend.
SMP2P becomes wakeup capable, to allow dying remoteprocs to wake up
Linux from suspend to perform recovery.
It adds RPM power-domain support for SM6350 and MSM8953 and base RPM
support for MSM8953 and QCM2290.
It adds support for MSM8996, SDM630 and SDM660 in the SPM driver, which
will enable the introduction of proper voltage scaling of the CPU
subsystem.
Support for releasing secondary CPUs on MSM8226 is introduced.
The Asynchronous Packet Router (APR) driver is extended to support the
new Generic Packet Router (GPR) variant, which is used to communicate
with the firmware in the new AudioReach audio driver.
Lastly it transitions a number of drivers to safer string functions, as
well as switching things to use devm_platform_ioremap_resource().
* tag 'qcom-drivers-for-5.16' of git://git.kernel.org/pub/scm/linux/kernel/git/qcom/linux: (40 commits)
soc: qcom: apr: Add GPR support
soc: dt-bindings: qcom: add gpr bindings
soc: qcom: apr: make code more reuseable
soc: dt-bindings: qcom: apr: deprecate qcom,apr-domain property
soc: dt-bindings: qcom: apr: convert to yaml
dt-bindings: soc: qcom: aoss: Delete unused power-domain definitions
dt-bindings: msm/dp: Remove aoss-qmp header
soc: qcom: aoss: Drop power domain support
dt-bindings: soc: qcom: aoss: Drop the load state power-domain
soc: qcom: smp2p: Add wakeup capability to SMP2P IRQ
dt-bindings: power: rpmpd: Add SM6350 to rpmpd binding
dt-bindings: soc: qcom: aoss: Add SM6350 compatible
soc: qcom: llcc: Disable MMUHWT retention
soc: qcom: smd-rpm: Add QCM2290 compatible
dt-bindings: soc: qcom: smd-rpm: Add QCM2290 compatible
firmware: qcom_scm: Add compatible for MSM8953 SoC
dt-bindings: firmware: qcom-scm: Document msm8953 bindings
soc: qcom: pdr: Prefer strscpy over strcpy
soc: qcom: rpmh-rsc: Make use of the helper function devm_platform_ioremap_resource_byname()
soc: qcom: gsbi: Make use of the helper function devm_platform_ioremap_resource()
...
Link: https://lore.kernel.org/r/20211012173442.1017010-1-bjorn.andersson@linaro.org
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Check whether PMC is ready before proceeding with the cpuidle registration.
This fixes racing with the PMC driver probe order, which results in a
disabled deepest CC6 idling state if cpuidle driver is probed before the
PMC.
Acked-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Signed-off-by: Dmitry Osipenko <digetx@gmail.com>
Signed-off-by: Thierry Reding <treding@nvidia.com>
Commit c343bf1ba5 ("cpuidle: Fix three reference count leaks")
fixes the cleanup of kobjects; however, it removes kfree() calls
altogether, leading to memory leaks.
Fix those and also defer the initialization of dev->kobj_dev until
after the error check, so that we do not end up with a dangling
pointer.
Fixes: c343bf1ba5 ("cpuidle: Fix three reference count leaks")
Signed-off-by: Anel Orazgaliyeva <anelkz@amazon.de>
Suggested-by: Aman Priyadarshi <apeureka@amazon.de>
[ rjw: Subject edits ]
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
In commit a871be6b8e ("cpuidle: Convert Qualcomm SPM driver to a generic
CPUidle driver") the SPM driver has been converted to a
generic CPUidle driver: that was mainly made to simplify the
driver and that was a great accomplishment;
Though, at that time, this driver was only applicable to ARM 32-bit SoCs,
lacking logic about the handling of newer generation SAW.
In preparation for the enablement of SPM features on AArch64/ARM64,
split the cpuidle-qcom-spm driver in two: the CPUIdle related
state machine (currently used only on ARM SoCs) stays there, while
the SPM communication handling lands back in soc/qcom/spm.c and
also making sure to not discard the simplifications that were
introduced in the aforementioned commit.
Since now the "two drivers" are split, the SCM dependency in the
main SPM handling is gone and for this reason it was also possible
to move the SPM initialization early: this will also make sure that
whenever the SAW CPUIdle driver is getting initialized, the SPM
driver will be ready to do the job.
Please note that the anticipation of the SPM initialization was
also done to optimize the boot times on platforms that have their
CPU/L2 idle states managed by other means (such as PSCI), while
needing SAW initialization for other purposes, like AVS control.
Signed-off-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@somainline.org>
Reviewed-by: Stephan Gerhold <stephan@gerhold.net>
Tested-by: Stephan Gerhold <stephan@gerhold.net>
Acked-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>
Link: https://lore.kernel.org/r/20210729155609.608159-2-angelogioacchino.delregno@somainline.org
Pull MFD updates from Lee Jones:
"Core Frameworks:
- Add support for registering devices via MFD cells to Simple MFD (I2C)
New Drivers:
- Add support for Renesas Synchronization Management Unit (SMU)
New Device Support:
- Add support for N5010 to Intel M10 BMC
- Add support for Cannon Lake to Intel LPSS ACPI
- Add support for Samsung SSG{1,2} to ST-Ericsson's U8500 family
- Add support for TQMx110EB and TQMxE40x to TQ-Systems PLD TQMx86
New Functionality:
- Add support for GPIO to Intel LPC ICH
- Add support for Reset to Texas Instruments TPS65086
Fix-ups:
- Trivial, sorting, whitespace, renaming, etc; mt6360-core, db8500-prcmu-regs, tqmx86
- Device Tree fiddling; syscon, axp20x, qcom,pm8008, ti,tps65086, brcm,cru
- Use proper APIs for IRQ map resolution; ab8500-core, stmpe, tc3589x, wm8994-irq
- Pass 'supplied-from' property through axp288_fuel_gauge via swnode
- Remove unused file entry; MAINTAINERS
- Make interrupt line optional; tps65086
- Rename db8500-cpuidle driver symbol; db8500-prcmu
- Remove support for unused hardware; tqmx86
- Provide a standard LPC clock frequency for unknown boards; tqmx86
- Remove unused code; ti_am335x_tscadc
- Use of_iomap() instead of ioremap(); syscon
Bug Fixes:
- Clear GPIO IRQ resource flags when no IRQ is set; tqmx86
- Fix incorrect/misleading frequencies; db8500-prcmu
- Mitigate namespace clash with other GPIOBASE users"
* tag 'mfd-next-5.15' of git://git.kernel.org/pub/scm/linux/kernel/git/lee/mfd: (31 commits)
mfd: lpc_sch: Rename GPIOBASE to prevent build error
mfd: syscon: Use of_iomap() instead of ioremap()
dt-bindings: mfd: Add Broadcom CRU
mfd: ti_am335x_tscadc: Delete superfluous error message
mfd: tqmx86: Assume 24MHz LPC clock for unknown boards
mfd: tqmx86: Add support for TQ-Systems DMI IDs
mfd: tqmx86: Add support for TQMx110EB and TQMxE40x
mfd: tqmx86: Fix typo in "platform"
mfd: tqmx86: Remove incorrect TQMx90UC board ID
mfd: tqmx86: Clear GPIO IRQ resource when no IRQ is set
mfd: simple-mfd-i2c: Add support for registering devices via MFD cells
mfd/cpuidle: ux500: Rename driver symbol
mfd: tps65086: Add cell entry for reset driver
mfd: tps65086: Make interrupt line optional
dt-bindings: mfd: Convert tps65086.txt to YAML
MAINTAINERS: Adjust ARM/NOMADIK/Ux500 ARCHITECTURES to file renaming
mfd: db8500-prcmu: Handle missing FW variant
mfd: db8500-prcmu: Rename register header
mfd: axp20x: Add supplied-from property to axp288_fuel_gauge cell
mfd: Don't use irq_create_mapping() to resolve a mapping
...
Pull powerpc updates from Michael Ellerman:
- Convert pseries & powernv to use MSI IRQ domains.
- Rework the pseries CPU numbering so that CPUs that are removed, and
later re-added, are given a CPU number on the same node as
previously, when possible.
- Add support for a new more flexible device-tree format for specifying
NUMA distances.
- Convert powerpc to GENERIC_PTDUMP.
- Retire sbc8548 and sbc8641d board support.
- Various other small features and fixes.
Thanks to Alexey Kardashevskiy, Aneesh Kumar K.V, Anton Blanchard,
Cédric Le Goater, Christophe Leroy, Emmanuel Gil Peyrot, Fabiano Rosas,
Fangrui Song, Finn Thain, Gautham R. Shenoy, Hari Bathini, Joel
Stanley, Jordan Niethe, Kajol Jain, Laurent Dufour, Leonardo Bras, Lukas
Bulwahn, Marc Zyngier, Masahiro Yamada, Michal Suchanek, Nathan
Chancellor, Nicholas Piggin, Parth Shah, Paul Gortmaker, Pratik R.
Sampat, Randy Dunlap, Sebastian Andrzej Siewior, Srikar Dronamraju, Wan
Jiabing, Xiongwei Song, and Zheng Yongjun.
* tag 'powerpc-5.15-1' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux: (154 commits)
powerpc/bug: Cast to unsigned long before passing to inline asm
powerpc/ptdump: Fix generic ptdump for 64-bit
KVM: PPC: Fix clearing never mapped TCEs in realmode
powerpc/pseries/iommu: Rename "direct window" to "dma window"
powerpc/pseries/iommu: Make use of DDW for indirect mapping
powerpc/pseries/iommu: Find existing DDW with given property name
powerpc/pseries/iommu: Update remove_dma_window() to accept property name
powerpc/pseries/iommu: Reorganize iommu_table_setparms*() with new helper
powerpc/pseries/iommu: Add ddw_property_create() and refactor enable_ddw()
powerpc/pseries/iommu: Allow DDW windows starting at 0x00
powerpc/pseries/iommu: Add ddw_list_new_entry() helper
powerpc/pseries/iommu: Add iommu_pseries_alloc_table() helper
powerpc/kernel/iommu: Add new iommu_table_in_use() helper
powerpc/pseries/iommu: Replace hard-coded page shift
powerpc/numa: Update cpu_cpu_map on CPU online/offline
powerpc/numa: Print debug statements only when required
powerpc/numa: convert printk to pr_xxx
powerpc/numa: Drop dbg in favour of pr_debug
powerpc/smp: Enable CACHE domain for shared processor
powerpc/smp: Update cpu_core_map on all PowerPc systems
...
The PRCMU driver defines this as a DT node but there are no bindings
for it and it needs no data from the device tree. Just spawn the
device directly in the same way as the watchdog.
Name it "db8500-cpuidle" since there are no ambitions to support any
more SoCs than this one.
This rids this annoying boot message:
[ 0.032610] cpuidle-dbx500: Failed to locate of_node [id: 0]
However I think the device still spawns and work just fine, despite
not finding a device tree node.
Cc: Rafael J. Wysocki <rjw@rjwysocki.net>
Cc: linux-pm@vger.kernel.org
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Acked-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Signed-off-by: Lee Jones <lee.jones@linaro.org>
After commit 7cbd631d4dec ("cpuidle: pseries: Fixup CEDE0 latency only
for POWER10 onwards"), pseries_idle_probe() is no longer inlined when
compiling with clang, which causes a modpost warning:
WARNING: modpost: vmlinux.o(.text+0xc86a54): Section mismatch in
reference from the function pseries_idle_probe() to the function
.init.text:fixup_cede0_latency()
The function pseries_idle_probe() references
the function __init fixup_cede0_latency().
This is often because pseries_idle_probe lacks a __init
annotation or the annotation of fixup_cede0_latency is wrong.
pseries_idle_probe() is a non-init function, which calls
fixup_cede0_latency(), which is an init function, explaining the
mismatch. pseries_idle_probe() is only called from
pseries_processor_idle_init(), which is an init function, so mark
pseries_idle_probe() as __init so there is no more warning.
Fixes: 054e44ba99 ("cpuidle: pseries: Add function to parse extended CEDE records")
Signed-off-by: Nathan Chancellor <nathan@kernel.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20210803211547.1093820-1-nathan@kernel.org
Rename two local variables in teo_select() so that their names better
reflect their purpose.
No functional impact.
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
There are three mistakes in the loop in teo_select() that is looking
for an alternative candidate idle state. First, it should walk all
of the idle states shallower than the current candidate one,
including all of the disabled ones, but it terminates after the first
enabled idle state. Second, it should not terminate its last step
if idle state 0 is disabled (which is related to the first issue).
Finally, it may return the current alternative candidate idle state
prematurely if the time span criterion is not met by the idle state
under consideration at the moment.
To address the issues mentioned above, make the loop in question walk
all of the idle states shallower than the current candidate idle state
all the way down to idle state 0 and rearrange the checks in it.
Fixes: 77577558f2 ("cpuidle: teo: Rework most recent idle duration values treatment")
Reported-by: Doug Smythies <dsmythies@telus.net>
Tested-by: Doug Smythies <dsmythies@telus.net>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Currently in fixup_cede0_latency() code, we perform the fixup the
CEDE(0) exit latency value only if minimum advertized extended CEDE
latency values are less than 10us. This was done so as to not break
the expected behaviour on POWER8 platforms where the advertised
latency was higher than the default 10us, which would delay the SMT
folding on the core.
However, after the earlier patch "cpuidle/pseries: Fixup CEDE0 latency
only for POWER10 onwards", we can be sure that the fixup of CEDE0
latency is going to happen only from POWER10 onwards. Hence
unconditionally use the minimum exit latency provided by the platform.
Signed-off-by: Gautham R. Shenoy <ego@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/1626676399-15975-3-git-send-email-ego@linux.vnet.ibm.com
Commit d947fb4c96 ("cpuidle: pseries: Fixup exit latency for
CEDE(0)") sets the exit latency of CEDE(0) based on the latency values
of the Extended CEDE states advertised by the platform
On POWER9 LPARs, the firmwares advertise a very low value of 2us for
CEDE1 exit latency on a Dedicated LPAR. The latency advertized by the
PHYP hypervisor corresponds to the latency required to wakeup from the
underlying hardware idle state. However the wakeup latency from the
LPAR perspective should include
1. The time taken to transition the CPU from the Hypervisor into the
LPAR post wakeup from platform idle state
2. Time taken to send the IPI from the source CPU (waker) to the idle
target CPU (wakee).
1. can be measured via timer idle test, where we queue a timer, say
for 1ms, and enter the CEDE state. When the timer fires, in the timer
handler we compute how much extra timer over the expected 1ms have we
consumed. On a a POWER9 LPAR the numbers are
CEDE latency measured using a timer (numbers in ns)
N Min Median Avg 90%ile 99%ile Max Stddev
400 2601 5677 5668.74 5917 6413 9299 455.01
1. and 2. combined can be determined by an IPI latency test where we
send an IPI to an idle CPU and in the handler compute the time
difference between when the IPI was sent and when the handler ran. We
see the following numbers on POWER9 LPAR.
CEDE latency measured using an IPI (numbers in ns)
N Min Median Avg 90%ile 99%ile Max Stddev
400 711 7564 7369.43 8559 9514 9698 1200.01
Suppose, we consider the 99th percentile latency value measured using
the IPI to be the wakeup latency, the value would be 9.5us This is in
the ballpark of the default value of 10us.
Hence, use the exit latency of CEDE(0) based on the latency values
advertized by platform only from POWER10 onwards. The values
advertized on POWER10 platforms is more realistic and informed by the
latency measurements. For earlier platforms stick to the default value
of 10us. The fix was suggested by Michael Ellerman.
Fixes: d947fb4c96 ("cpuidle: pseries: Fixup exit latency for CEDE(0)")
Reported-by: Enrico Joedecke <joedecke@de.ibm.com>
Signed-off-by: Gautham R. Shenoy <ego@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/1626676399-15975-2-git-send-email-ego@linux.vnet.ibm.com
Pull ARM cpuidle updates for v5.14 from Daniel Lezcano:
"- Add support for Qcom MSM8226 (Bartosz Dudziak)"
* tag 'cpuidle-v5.14-rc1' of https://git.linaro.org/people/daniel.lezcano/linux:
cpuidle: qcom: Add SPM register data for MSM8226
dt-bindings: arm: msm: Add SAW2 for MSM8226
Pull power management updates from Rafael Wysocki:
"These add hybrid processors support to the intel_pstate driver and
make it work with more processor models when HWP is disabled, make the
intel_idle driver use special C6 idle state paremeters when package
C-states are disabled, add cooling support to the tegra30 devfreq
driver, rework the TEO (timer events oriented) cpuidle governor,
extend the OPP (operating performance points) framework to use the
required-opps DT property in more cases, fix some issues and clean up
a number of assorted pieces of code.
Specifics:
- Make intel_pstate support hybrid processors using abstract
performance units in the HWP interface (Rafael Wysocki).
- Add Icelake servers and Cometlake support in no-HWP mode to
intel_pstate (Giovanni Gherdovich).
- Make cpufreq_online() error path be consistent with the CPU device
removal path in cpufreq (Rafael Wysocki).
- Clean up 3 cpufreq drivers and the statistics code (Hailong Liu,
Randy Dunlap, Shaokun Zhang).
- Make intel_idle use special idle state parameters for C6 when
package C-states are disabled (Chen Yu).
- Rework the TEO (timer events oriented) cpuidle governor to address
some theoretical shortcomings in it (Rafael Wysocki).
- Drop unneeded semicolon from the TEO governor (Wan Jiabing).
- Modify the runtime PM framework to accept unassigned suspend and
resume callback pointers (Ulf Hansson).
- Improve pm_runtime_get_sync() documentation (Krzysztof Kozlowski).
- Improve device performance states support in the generic power
domains (genpd) framework (Ulf Hansson).
- Fix some documentation issues in genpd (Yang Yingliang).
- Make the operating performance points (OPP) framework use the
required-opps DT property in use cases that are not related to
genpd (Hsin-Yi Wang).
- Make lazy_link_required_opp_table() use list_del_init instead of
list_del/INIT_LIST_HEAD (Yang Yingliang).
- Simplify wake IRQs handling in the core system-wide sleep support
code and clean up some coding style inconsistencies in it (Tian
Tao, Zhen Lei).
- Add cooling support to the tegra30 devfreq driver and improve its
DT bindings (Dmitry Osipenko).
- Fix some assorted issues in the devfreq core and drivers (Chanwoo
Choi, Dong Aisheng, YueHaibing)"
* tag 'pm-5.14-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm: (39 commits)
PM / devfreq: passive: Fix get_target_freq when not using required-opp
cpufreq: Make cpufreq_online() call driver->offline() on errors
opp: Allow required-opps to be used for non genpd use cases
cpuidle: teo: remove unneeded semicolon in teo_select()
dt-bindings: devfreq: tegra30-actmon: Add cooling-cells
dt-bindings: devfreq: tegra30-actmon: Convert to schema
PM / devfreq: userspace: Use DEVICE_ATTR_RW macro
PM: runtime: Clarify documentation when callbacks are unassigned
PM: runtime: Allow unassigned ->runtime_suspend|resume callbacks
PM: runtime: Improve path in rpm_idle() when no callback
PM: hibernate: remove leading spaces before tabs
PM: sleep: remove trailing spaces and tabs
PM: domains: Drop/restore performance state votes for devices at runtime PM
PM: domains: Return early if perf state is already set for the device
PM: domains: Split code in dev_pm_genpd_set_performance_state()
cpuidle: teo: Use kerneldoc documentation in admin-guide
cpuidle: teo: Rework most recent idle duration values treatment
cpuidle: teo: Change the main idle state selection logic
cpuidle: teo: Cosmetic modification of teo_select()
cpuidle: teo: Cosmetic modifications of teo_update()
...
Fix following coccicheck warning:
drivers/cpuidle/governors/teo.c:315:10-11: Unneeded semicolon
Signed-off-by: Wan Jiabing <wanjiabing@vivo.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
There are two descriptions of the TEO (Timer Events Oriented) cpuidle
governor in the kernel source tree, one in the C file containing its
code and one in cpuidle.rst which is part of admin-guide.
Instead of trying to keep them both in sync and in order to reduce
text duplication, include the governor description from the C file
directly into cpuidle.rst.
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
The TEO (Timer Events Oriented) cpuidle governor uses several most
recent idle duration values for a given CPU to refine the idle state
selection in case the previous long-term trends have not been
followed recently and a new trend appears to be forming. That is
done by computing the average of the most recent idle duration
values falling below the time till the next timer event ("sleep
length"), provided that they are the majority of the most recent
idle duration values taken into account, and using it as the new
expected idle duration value.
However, idle state selection based on that value may not be optimal,
because the average does not really indicate which of the idle states
with target residencies less than or equal to it is likely to be the
best fit.
Thus, instead of computing the average, make the governor carry out
computations based on the distribution of the most recent idle
duration values among the bins corresponding to different idle
states. Namely, if the majority of the most recent idle duration
values taken into consideration are less than the current sleep
length (which means that the CPU is likely to wake up early), find
the idle state closest to the "candidate" one "matching" the sleep
length whose target residency is less than or equal to the majority
of the most recent idle duration values that have fallen below the
current sleep length (which means that it is likely to be "shallow
enough" this time).
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Two aspects of the current main idle state selection logic in the
TEO (Timer Events Oriented) cpuidle governor are quite questionable.
First of all, the "hits" and "misses" metrics used by it are only
updated for a given idle state if the time till the next timer event
("sleep length") is between the target residency of that state and
the target residency of the next one. Consequently, they are likely
to become stale if the sleep length tends to fall outside that
interval which increases the likelihood of subomtimal idle state
selection.
Second, the decision on whether or not to select the idle state
"matching" the sleep length is based on the metrics collected for
that state alone, whereas in principle the metrics collected for
the other idle states should be taken into consideration when that
decision is made. For example, if the measured idle duration is less
than the target residency of the idle state "matching" the sleep
length, then it is also less than the target residency of any deeper
idle state and that should be taken into account when considering
whether or not to select any of those states, but currently it is
not.
In order to address the above shortcomings, modify the main idle
state selection logic in the TEO governor to take the metrics
collected for all of the idle states into account when deciding
whether or not to select the one "matching" the sleep length.
Moreover, drop the "misses" metric that becomes redundant after the
above change and rename the "early_hits" metric to "intercepts" so
that its role is better reflected by its name (the idea being that
if a CPU wakes up earlier than indicated by the sleep length, then
it must be a result of a non-timer interrupt that "intercepts" the
CPU).
Also rename the states[] array in struct struct teo_cpu to
state_bins[] to avoid confusing it with the states[] array in
struct cpuidle_driver and update the documentation to match the
new code (and make it more comprehensive while at it).
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Initialize local variables in teo_select() where they are declared.
No functional impact.
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Rename a local variable in teo_update() so that its purpose is better
reflected by its name and use one more local variable in the loop
over the CPU idle states in that function to make the code somewhat
easier to read.
No functional impact.
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
