Commit Graph

134 Commits

Author SHA1 Message Date
Linus Torvalds
1e0c505e13 asm-generic updates for v6.7
The ia64 architecture gets its well-earned retirement as planned,
 now that there is one last (mostly) working release that will
 be maintained as an LTS kernel.
 
 The architecture specific system call tables are updated for
 the added map_shadow_stack() syscall and to remove references
 to the long-gone sys_lookup_dcookie() syscall.
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Merge tag 'asm-generic-6.7' of git://git.kernel.org/pub/scm/linux/kernel/git/arnd/asm-generic

Pull ia64 removal and asm-generic updates from Arnd Bergmann:

 - The ia64 architecture gets its well-earned retirement as planned,
   now that there is one last (mostly) working release that will be
   maintained as an LTS kernel.

 - The architecture specific system call tables are updated for the
   added map_shadow_stack() syscall and to remove references to the
   long-gone sys_lookup_dcookie() syscall.

* tag 'asm-generic-6.7' of git://git.kernel.org/pub/scm/linux/kernel/git/arnd/asm-generic:
  hexagon: Remove unusable symbols from the ptrace.h uapi
  asm-generic: Fix spelling of architecture
  arch: Reserve map_shadow_stack() syscall number for all architectures
  syscalls: Cleanup references to sys_lookup_dcookie()
  Documentation: Drop or replace remaining mentions of IA64
  lib/raid6: Drop IA64 support
  Documentation: Drop IA64 from feature descriptions
  kernel: Drop IA64 support from sig_fault handlers
  arch: Remove Itanium (IA-64) architecture
2023-11-01 15:28:33 -10:00
Pierre Gondois
5b77261c55 sched/topology: Remove the EM_MAX_COMPLEXITY limit
The Energy Aware Scheduler (EAS) estimates the energy consumption
of placing a task on different CPUs. The goal is to minimize this
energy consumption. Estimating the energy of different task placements
is increasingly complex with the size of the platform.

To avoid having a slow wake-up path, EAS is only enabled if this
complexity is low enough.

The current complexity limit was set in:

  b68a4c0dba ("sched/topology: Disable EAS on inappropriate platforms")

... based on the first implementation of EAS, which was re-computing
the power of the whole platform for each task placement scenario, see:

  390031e4c3 ("sched/fair: Introduce an energy estimation helper function")

... but the complexity of EAS was reduced in:

  eb92692b25 ("sched/fair: Speed-up energy-aware wake-ups")

... and find_energy_efficient_cpu() (feec) algorithm was updated in:

  3e8c6c9aac ("sched/fair: Remove task_util from effective utilization in feec()")

find_energy_efficient_cpu() (feec) is now doing:

	feec()
	\_ for_each_pd(pd) [0]
	  // get max_spare_cap_cpu and compute_prev_delta
	  \_ for_each_cpu(pd) [1]

	  \_ eenv_pd_busy_time(pd) [2]
		\_ for_each_cpu(pd)

	  // compute_energy(pd) without the task
	  \_ eenv_pd_max_util(pd, -1) [3.0]
	    \_ for_each_cpu(pd)
	  \_ em_cpu_energy(pd, -1)
	    \_ for_each_ps(pd)

	  // compute_energy(pd) with the task on prev_cpu
	  \_ eenv_pd_max_util(pd, prev_cpu) [3.1]
	    \_ for_each_cpu(pd)
	  \_ em_cpu_energy(pd, prev_cpu)
	    \_ for_each_ps(pd)

	  // compute_energy(pd) with the task on max_spare_cap_cpu
	  \_ eenv_pd_max_util(pd, max_spare_cap_cpu) [3.2]
	    \_ for_each_cpu(pd)
	  \_ em_cpu_energy(pd, max_spare_cap_cpu)
	    \_ for_each_ps(pd)

	[3.1] happens only once since prev_cpu is unique. With the same
	      definitions for nr_pd, nr_cpus and nr_ps, the complexity is of:

		nr_pd * (2 * [nr_cpus in pd] + 2 * ([nr_cpus in pd] + [nr_ps in pd]))
		+ ([nr_cpus in pd] + [nr_ps in pd])

		 [0]  * (     [1] + [2]      +       [3.0] + [3.2]                  )
		+ [3.1]

		= nr_pd * (4 * [nr_cpus in pd] + 2 * [nr_ps in pd])
		+ [nr_cpus in prev pd] + nr_ps

The complexity limit was set to 2048 in:

  b68a4c0dba ("sched/topology: Disable EAS on inappropriate platforms")

... to make "EAS usable up to 16 CPUs with per-CPU DVFS and less than 8
performance states each". For the same platform, the complexity would
actually be of:

  16 * (4 + 2 * 7) + 1 + 7 = 296

Since the EAS complexity was greatly reduced since the limit was
introduced, bigger platforms can handle EAS.

For instance, a platform with 112 CPUs with 7 performance states
each would not reach it:

  112 * (4 + 2 * 7) + 1 + 7 = 2024

To reflect this improvement in the underlying EAS code, remove
the EAS complexity check.

Note that a limit on the number of CPUs still holds against
EM_MAX_NUM_CPUS to avoid overflows during the energy estimation.

[ mingo: Updates to the changelog. ]

Signed-off-by: Pierre Gondois <Pierre.Gondois@arm.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Reviewed-by: Lukasz Luba <lukasz.luba@arm.com>
Reviewed-by: Dietmar Eggemann <dietmar.eggemann@arm.com>
Link: https://lore.kernel.org/r/20231009060037.170765-2-sshegde@linux.vnet.ibm.com
2023-10-09 13:07:27 +02:00
Vincent Guittot
7bc263840b sched/topology: Consolidate and clean up access to a CPU's max compute capacity
Remove the rq::cpu_capacity_orig field and use arch_scale_cpu_capacity()
instead.

The scheduler uses 3 methods to get access to a CPU's max compute capacity:

 - arch_scale_cpu_capacity(cpu) which is the default way to get a CPU's capacity.

 - cpu_capacity_orig field which is periodically updated with
   arch_scale_cpu_capacity().

 - capacity_orig_of(cpu) which encapsulates rq->cpu_capacity_orig.

There is no real need to save the value returned by arch_scale_cpu_capacity()
in struct rq. arch_scale_cpu_capacity() returns:

 - either a per_cpu variable.

 - or a const value for systems which have only one capacity.

Remove rq::cpu_capacity_orig and use arch_scale_cpu_capacity() everywhere.

No functional changes.

Some performance tests on Arm64:

  - small SMP device (hikey): no noticeable changes
  - HMP device (RB5):         hackbench shows minor improvement (1-2%)
  - large smp (thx2):         hackbench and tbench shows minor improvement (1%)

Signed-off-by: Vincent Guittot <vincent.guittot@linaro.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Reviewed-by: Dietmar Eggemann <dietmar.eggemann@arm.com>
Link: https://lore.kernel.org/r/20231009103621.374412-2-vincent.guittot@linaro.org
2023-10-09 12:59:48 +02:00
Cyril Hrubis
83494dc510 sched/rt/docs: Use 'real-time' instead of 'realtime'
Standardize on a single variant.

Signed-off-by: Cyril Hrubis <chrubis@suse.cz>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Link: https://lore.kernel.org/r/20231002115553.3007-4-chrubis@suse.cz
2023-10-02 15:17:14 +02:00
Cyril Hrubis
e6dbdd8fb7 sched/rt/docs: Clarify & fix sched_rt_* sysctl docs
- Describe explicitly that sched_rt_runtime_us is allocated from
  sched_rt_period_us and hence always less or equal to that value.

- The limit for sched_rt_runtime_us is not INT_MAX-1, but rather it's
  limited by the value of sched_rt_period_us. If sched_rt_period_us is
  INT_MAX then sched_rt_runtime_us can be set to INT_MAX as well.

Signed-off-by: Cyril Hrubis <chrubis@suse.cz>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Link: https://lore.kernel.org/r/20231002115553.3007-3-chrubis@suse.cz
2023-10-02 15:17:13 +02:00
Ard Biesheuvel
944834901a Documentation: Drop or replace remaining mentions of IA64
Drop or update mentions of IA64, as appropriate.

Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
2023-09-11 08:13:18 +00:00
Linus Torvalds
cd99b9eb4b Documentation work keeps chugging along; stuff for 6.6 includes:
- Work from Carlos Bilbao to integrate rustdoc output into the generated
   HTML documentation.  This took some work to figure out how to do it
   without slowing the docs build and without creating people who don't have
   Rust installed, but Carlos got there.
 
 - Move the loongarch and mips architecture documentation under
   Documentation/arch/.
 
 - Some more maintainer documentation from Jakub
 
 ...plus the usual assortment of updates, translations, and fixes.
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Merge tag 'docs-6.6' of git://git.lwn.net/linux

Pull documentation updates from Jonathan Corbet:
 "Documentation work keeps chugging along; this includes:

   - Work from Carlos Bilbao to integrate rustdoc output into the
     generated HTML documentation. This took some work to figure out how
     to do it without slowing the docs build and without creating people
     who don't have Rust installed, but Carlos got there

   - Move the loongarch and mips architecture documentation under
     Documentation/arch/

   - Some more maintainer documentation from Jakub

  ... plus the usual assortment of updates, translations, and fixes"

* tag 'docs-6.6' of git://git.lwn.net/linux: (56 commits)
  Docu: genericirq.rst: fix irq-example
  input: docs: pxrc: remove reference to phoenix-sim
  Documentation: serial-console: Fix literal block marker
  docs/mm: remove references to hmm_mirror ops and clean typos
  docs/zh_CN: correct regi_chg(),regi_add() to region_chg(),region_add()
  Documentation: Fix typos
  Documentation/ABI: Fix typos
  scripts: kernel-doc: fix macro handling in enums
  scripts: kernel-doc: parse DEFINE_DMA_UNMAP_[ADDR|LEN]
  Documentation: riscv: Update boot image header since EFI stub is supported
  Documentation: riscv: Add early boot document
  Documentation: arm: Add bootargs to the table of added DT parameters
  docs: kernel-parameters: Refer to the correct bitmap function
  doc: update params of memhp_default_state=
  docs: Add book to process/kernel-docs.rst
  docs: sparse: fix invalid link addresses
  docs: vfs: clean up after the iterate() removal
  docs: Add a section on surveys to the researcher guidelines
  docs: move mips under arch
  docs: move loongarch under arch
  ...
2023-08-30 20:05:42 -07:00
Shrikanth Hegde
2f88c8e802 sched/eevdf/doc: Modify the documented knob to base_slice_ns as well
After committing the scheduler to EEVDF, we renamed the 'min_granularity_ns'
sysctl to 'base_slice_ns':

   e4ec3318a1 ("sched/debug: Rename sysctl_sched_min_granularity to sysctl_sched_base_slice")

... but we forgot to rename it in the documentation. Do that now.

Fixes: e4ec3318a1 ("sched/debug: Rename sysctl_sched_min_granularity to sysctl_sched_base_slice")
Signed-off-by: Shrikanth Hegde <sshegde@linux.vnet.ibm.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: https://lore.kernel.org/r/20230824080342.543396-1-sshegde@linux.vnet.ibm.com
2023-08-24 21:31:57 +02:00
Bjorn Helgaas
d56b699d76 Documentation: Fix typos
Fix typos in Documentation.

Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Link: https://lore.kernel.org/r/20230814212822.193684-4-helgaas@kernel.org
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
2023-08-18 11:29:03 -06:00
Rick Wertenbroek
f98b161b0d docs: scheduler: completion: Fix minor error in pseudo-code
Add missing address-of (&) operator in pseudo-code.

Signed-off-by: Rick Wertenbroek <rick.wertenbroek@gmail.com>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Link: https://lore.kernel.org/r/20230706114057.1120335-1-rick.wertenbroek@gmail.com
2023-07-14 13:08:07 -06:00
Vineeth Pillai
e20f204c88 sched/deadline: Update GRUB description in the documentation
Update the details of GRUB to reflect the updated logic.

Signed-off-by: Vineeth Pillai (Google) <vineeth@bitbyteword.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Daniel Bristot de Oliveira <bristot@kernel.org>
Acked-by: Juri Lelli <juri.lelli@redhat.com>
Link: https://lore.kernel.org/r/20230530135526.2385378-2-vineeth@bitbyteword.org
2023-06-16 22:08:12 +02:00
Linus Torvalds
513f17f8d6 sh updates for v6.4
- sh: Use generic GCC library routines
 - sh: sq: Use the bitmap API when applicable
 - sh: sq: Fix incorrect element size for allocating bitmap buffer
 - sh: pci: Remove unused variable in SH-7786 PCI Express code
 - sh: mcount.S: fix build error when PRINTK is not enabled
 - sh: remove sh5/sh64 last fragments
 - sh: math-emu: fix macro redefined warning
 - sh: init: use OF_EARLY_FLATTREE for early init
 - sh: nmi_debug: fix return value of __setup handler
 - sh: SH2007: drop the bad URL info
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Merge tag 'sh-for-v6.4-tag1' of git://git.kernel.org/pub/scm/linux/kernel/git/glaubitz/sh-linux

Pull sh updates from John Paul Adrian Glaubitz:
 "This is a bit larger than my previous one and mainly consists of
  clean-up work in the arch/sh directory by Geert Uytterhoeven and Randy
  Dunlap.

  Additionally, this fixes a bug in the Storage Queue code that was
  discovered while I was reviewing a patch to switch the code to the
  bitmap API by Christophe Jaillet.

  So this contains both a fix for the original bug in the Storage Queue
  code that can be backported later as well as the Christophe's patch to
  swich the code to the bitmap API.

  Summary:

   - Use generic GCC library routines

   - sq: Use the bitmap API when applicable

   - sq: Fix incorrect element size for allocating bitmap buffer

   - pci: Remove unused variable in SH-7786 PCI Express code

   - mcount.S: fix build error when PRINTK is not enabled

   - remove sh5/sh64 last fragments

   - math-emu: fix macro redefined warning

   - init: use OF_EARLY_FLATTREE for early init

   - nmi_debug: fix return value of __setup handler

   - SH2007: drop the bad URL info"

* tag 'sh-for-v6.4-tag1' of git://git.kernel.org/pub/scm/linux/kernel/git/glaubitz/sh-linux:
  sh: Replace <uapi/asm/types.h> by <asm-generic/int-ll64.h>
  sh: Use generic GCC library routines
  sh: sq: Use the bitmap API when applicable
  sh: sq: Fix incorrect element size for allocating bitmap buffer
  sh: pci: Remove unused variable in SH-7786 PCI Express code
  sh: mcount.S: fix build error when PRINTK is not enabled
  sh: remove sh5/sh64 last fragments
  sh: math-emu: fix macro redefined warning
  sh: init: use OF_EARLY_FLATTREE for early init
  sh: nmi_debug: fix return value of __setup handler
  sh: SH2007: drop the bad URL info
2023-04-27 17:41:23 -07:00
Randy Dunlap
644a9cf0d2 sh: remove sh5/sh64 last fragments
A previous patch removed most of the sh5 (sh64) support from the
kernel tree. Now remove the last stragglers.

Fixes: 37744feebc ("sh: remove sh5 support")
Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Cc: Geert Uytterhoeven <geert+renesas@glider.be>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Rich Felker <dalias@libc.org>
Cc: Yoshinori Sato <ysato@users.sourceforge.jp>
Cc: John Paul Adrian Glaubitz <glaubitz@physik.fu-berlin.de>
Cc: linux-sh@vger.kernel.org
Acked-by: John Paul Adrian Glaubitz <glaubitz@physik.fu-berlin.de>
Reviewed-by: John Paul Adrian Glaubitz <glaubitz@physik.fu-berlin.de>
Link: https://lore.kernel.org/r/20230306040037.20350-6-rdunlap@infradead.org
Signed-off-by: John Paul Adrian Glaubitz <glaubitz@physik.fu-berlin.de>
2023-03-23 10:02:02 +01:00
Song Shuai
5d89176af1 sched/doc: supplement CPU capacity with RISC-V
This commit 7d2078310c ("dt-bindings: arm: move cpu-capacity to a
shared loation") updates some references about capacity-dmips-mhz
property in this document.

The list of architectures using capacity-dmips-mhz omits RISC-V, so
supplements it here.

Signed-off-by: Song Shuai <suagrfillet@gmail.com>
Reviewed-by: Palmer Dabbelt <palmer@rivosinc.com> # English
Acked-by: Palmer Dabbelt <palmer@rivosinc.com>
Reviewed-by: Alex Shi <alexs@kernel.org>
Reviewed-by: Conor Dooley <conor.dooley@microchip.com>
Link: https://lore.kernel.org/r/20230227105941.2749193-1-suagrfillet@gmail.com
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
2023-03-07 10:19:04 -07:00
Linus Torvalds
01687e7c93 RISC-V Patches for the 6.3 Merge Window, Part 1
There's a bunch of fixes/cleanups throughout the tree as usual, but we
 also have a handful of new features.
 
 * Various improvements to the extension detection and alternative
   patching infrastructure.
 * Zbb-optimized string routines.
 * Support for cpu-capacity in the RISC-V DT bindings.
 * Zicbom no longer depends on toolchain support.
 * Some performance and code size improvements to ftrace.
 * Support for ARCH_WANT_LD_ORPHAN_WARN.
 * Oops now contain the faulting instruction.
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Merge tag 'riscv-for-linus-6.3-mw1' of git://git.kernel.org/pub/scm/linux/kernel/git/riscv/linux

Pull RISC-V updates from Palmer Dabbelt:
 "There's a bunch of fixes/cleanups throughout the tree as usual, but we
  also have a handful of new features:

   - Various improvements to the extension detection and alternative
     patching infrastructure

   - Zbb-optimized string routines

   - Support for cpu-capacity in the RISC-V DT bindings

   - Zicbom no longer depends on toolchain support

   - Some performance and code size improvements to ftrace

   - Support for ARCH_WANT_LD_ORPHAN_WARN

   - Oops now contain the faulting instruction"

* tag 'riscv-for-linus-6.3-mw1' of git://git.kernel.org/pub/scm/linux/kernel/git/riscv/linux: (67 commits)
  RISC-V: add a spin_shadow_stack declaration
  riscv: mm: hugetlb: Enable ARCH_WANT_HUGETLB_PAGE_OPTIMIZE_VMEMMAP
  riscv: Add header include guards to insn.h
  riscv: alternative: proceed one more instruction for auipc/jalr pair
  riscv: Avoid enabling interrupts in die()
  riscv, mm: Perform BPF exhandler fixup on page fault
  RISC-V: take text_mutex during alternative patching
  riscv: hwcap: Don't alphabetize ISA extension IDs
  RISC-V: fix ordering of Zbb extension
  riscv: jump_label: Fixup unaligned arch_static_branch function
  RISC-V: Only provide the single-letter extensions in HWCAP
  riscv: mm: fix regression due to update_mmu_cache change
  scripts/decodecode: Add support for RISC-V
  riscv: Add instruction dump to RISC-V splats
  riscv: select ARCH_WANT_LD_ORPHAN_WARN for !XIP_KERNEL
  riscv: vmlinux.lds.S: explicitly catch .init.bss sections from EFI stub
  riscv: vmlinux.lds.S: explicitly catch .riscv.attributes sections
  riscv: vmlinux.lds.S: explicitly catch .rela.dyn symbols
  riscv: lds: define RUNTIME_DISCARD_EXIT
  RISC-V: move some stray __RISCV_INSN_FUNCS definitions from kprobes
  ...
2023-02-25 11:14:08 -08:00
Linus Torvalds
70756b49be It has been a moderately calm cycle for documentation; the significant
changes include:
 
 - Some significant additions to the memory-management documentation
 
 - Some improvements to navigation in the HTML-rendered docs
 
 - More Spanish and Chinese translations
 
 ...and the usual set of typo fixes and such.
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Merge tag 'docs-6.3' of git://git.lwn.net/linux

Pull documentation updates from Jonathan Corbet:
 "It has been a moderately calm cycle for documentation; the significant
  changes include:

   - Some significant additions to the memory-management documentation

   - Some improvements to navigation in the HTML-rendered docs

   - More Spanish and Chinese translations

  ... and the usual set of typo fixes and such"

* tag 'docs-6.3' of git://git.lwn.net/linux: (68 commits)
  Documentation/watchdog/hpwdt: Fix Format
  Documentation/watchdog/hpwdt: Fix Reference
  Documentation: core-api: padata: correct spelling
  docs/mm: Physical Memory: correct spelling in reference to CONFIG_PAGE_EXTENSION
  docs: Use HTML comments for the kernel-toc SPDX line
  docs: Add more information to the HTML sidebar
  Documentation: KVM: Update AMD memory encryption link
  printk: Document that CONFIG_BOOT_PRINTK_DELAY required for boot_delay=
  Documentation: userspace-api: correct spelling
  Documentation: sparc: correct spelling
  Documentation: driver-api: correct spelling
  Documentation: admin-guide: correct spelling
  docs: add workload-tracing document to admin-guide
  docs/admin-guide/mm: remove useless markup
  docs/mm: remove useless markup
  docs/mm: Physical Memory: remove useless markup
  docs/sp_SP: Add process magic-number translation
  docs: ftrace: always use canonical ftrace path
  Doc/damon: fix the data path error
  dma-buf: Add "dma-buf" to title of documentation
  ...
2023-02-22 12:00:20 -08:00
Conor Dooley
7d2078310c
dt-bindings: arm: move cpu-capacity to a shared loation
RISC-V uses the same generic topology code as arm64 & while there
currently exists no binding for cpu-capacity on RISC-V, the code paths
can be hit if the property is present.

Move the documentation of cpu-capacity to a shared location, ahead of
defining a binding for capacity-dmips-mhz on RISC-V. Update some
references to this document in the process.

Signed-off-by: Conor Dooley <conor.dooley@microchip.com>
Reviewed-by: Ley Foon Tan <leyfoon.tan@starfivetech.com>
Acked-by: Rob Herring <robh@kernel.org>
Reviewed-by: Yanteng Si <siyanteng@loongson.cn>
Link: https://lore.kernel.org/r/20230104180513.1379453-2-conor@kernel.org
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
2023-02-14 19:24:05 -08:00
SeongJae Park
941c95fdd6 Docs/subsystem-apis: Remove '[The ]Linux' prefixes from titles of listed documents
Some documents that listed on subsystem-apis have 'Linux' or 'The Linux'
title prefixes.  It's duplicated information, and makes finding the
document of interest with human eyes not easy.  Remove the prefixes from
the titles.

Signed-off-by: SeongJae Park <sj@kernel.org>
Acked-by: Iwona Winiarska <iwona.winiarska@intel.com>
Acked-by: Bjorn Helgaas <bhelgaas@google.com>
Link: https://lore.kernel.org/r/20230122184834.181977-1-sj@kernel.org
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
2023-01-24 15:27:08 -07:00
Qais Yousef
acbee592f1 sched/documentation: Document the util clamp feature
Add a document explaining the util clamp feature: what it is and
how to use it. The new document hopefully covers everything one needs to
know about uclamp.

Signed-off-by: Qais Yousef <qais.yousef@arm.com>
Signed-off-by: Qais Yousef (Google) <qyousef@layalina.io>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Reviewed-by: Lukasz Luba <lukasz.luba@arm.com>
Link: https://lore.kernel.org/r/20221216235716.201923-1-qyousef@layalina.io
Cc: Jonathan Corbet <corbet@lwn.net>
2023-01-05 12:08:34 +01:00
Lukasz Luba
363fd2324c docs: scheduler: Update new path for the sysctl knobs
Add missing update for the documentation bit of some scheduler knob.
The knobs have been moved to /debug/sched/ location (with adjusted names).

Signed-off-by: Lukasz Luba <lukasz.luba@arm.com>
Reviewed-by: Alex Shi <alexs@kernel.org>
Tested-by: Yanteng Si <siyanteng@loongson.cn>
Link: https://lore.kernel.org/r/20220816121907.841-1-lukasz.luba@arm.com
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
2022-09-27 13:21:42 -06:00
Jui-Tse Huang
6c757e9f55 docs/scheduler: fix unit error
The unit mentioned in the documentation of scheduler statistics is
outdated which may mislead the readers.

The unit of statistics that is reported by /proc/schedstat is modified
to nanosecond, and the unit of statistics that is reported by
/proc/PID/schedstat is provided as well to make the context consistent.

The rq_cpu_time and the rq_sched_info.run_delay of a run queue, and the
sched_info.run_delay of a task are all updated based on the clock of the
run queue, while the se.sum_exec_runtime of a task is updated based on
the clock_task of the run queue of the task. Both the clock and
clock_task are relied on the return value of the function sched_clock()
which is in the unit of nanosecond.

Signed-off-by: Jui-Tse Huang <juitse.huang@gmail.com>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
2022-04-16 02:54:32 -06:00
Chunguang Xu
ddb21d27a6 docs/scheduler: Change unit of cpu_time and rq_time to nanoseconds
In the current implementation, cpu_time and rq_time should be
in nanoseconds, so this document needs to be modified.

Signed-off-by: Chunguang Xu <brookxu@tencent.com>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
2022-04-16 02:35:51 -06:00
Linus Torvalds
3fe2f7446f Changes in this cycle were:
- Cleanups for SCHED_DEADLINE
  - Tracing updates/fixes
  - CPU Accounting fixes
  - First wave of changes to optimize the overhead of the scheduler build,
    from the fast-headers tree - including placeholder *_api.h headers for
    later header split-ups.
  - Preempt-dynamic using static_branch() for ARM64
  - Isolation housekeeping mask rework; preperatory for further changes
  - NUMA-balancing: deal with CPU-less nodes
  - NUMA-balancing: tune systems that have multiple LLC cache domains per node (eg. AMD)
  - Updates to RSEQ UAPI in preparation for glibc usage
  - Lots of RSEQ/selftests, for same
  - Add Suren as PSI co-maintainer
 
 Signed-off-by: Ingo Molnar <mingo@kernel.org>
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Merge tag 'sched-core-2022-03-22' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull scheduler updates from Ingo Molnar:

 - Cleanups for SCHED_DEADLINE

 - Tracing updates/fixes

 - CPU Accounting fixes

 - First wave of changes to optimize the overhead of the scheduler
   build, from the fast-headers tree - including placeholder *_api.h
   headers for later header split-ups.

 - Preempt-dynamic using static_branch() for ARM64

 - Isolation housekeeping mask rework; preperatory for further changes

 - NUMA-balancing: deal with CPU-less nodes

 - NUMA-balancing: tune systems that have multiple LLC cache domains per
   node (eg. AMD)

 - Updates to RSEQ UAPI in preparation for glibc usage

 - Lots of RSEQ/selftests, for same

 - Add Suren as PSI co-maintainer

* tag 'sched-core-2022-03-22' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (81 commits)
  sched/headers: ARM needs asm/paravirt_api_clock.h too
  sched/numa: Fix boot crash on arm64 systems
  headers/prep: Fix header to build standalone: <linux/psi.h>
  sched/headers: Only include <linux/entry-common.h> when CONFIG_GENERIC_ENTRY=y
  cgroup: Fix suspicious rcu_dereference_check() usage warning
  sched/preempt: Tell about PREEMPT_DYNAMIC on kernel headers
  sched/topology: Remove redundant variable and fix incorrect type in build_sched_domains
  sched/deadline,rt: Remove unused parameter from pick_next_[rt|dl]_entity()
  sched/deadline,rt: Remove unused functions for !CONFIG_SMP
  sched/deadline: Use __node_2_[pdl|dle]() and rb_first_cached() consistently
  sched/deadline: Merge dl_task_can_attach() and dl_cpu_busy()
  sched/deadline: Move bandwidth mgmt and reclaim functions into sched class source file
  sched/deadline: Remove unused def_dl_bandwidth
  sched/tracing: Report TASK_RTLOCK_WAIT tasks as TASK_UNINTERRUPTIBLE
  sched/tracing: Don't re-read p->state when emitting sched_switch event
  sched/rt: Plug rt_mutex_setprio() vs push_rt_task() race
  sched/cpuacct: Remove redundant RCU read lock
  sched/cpuacct: Optimize away RCU read lock
  sched/cpuacct: Fix charge percpu cpuusage
  sched/headers: Reorganize, clean up and optimize kernel/sched/sched.h dependencies
  ...
2022-03-22 14:39:12 -07:00
Tang Yizhou
b57b849688 docs: scheduler: Convert schedutil.txt to ReST
All other scheduler documents have been converted to *.rst. Let's do
the same for schedutil.txt.

Also fixed some typos.

Signed-off-by: Tang Yizhou <tangyizhou@huawei.com>
Link: https://lore.kernel.org/r/20220312070751.16844-1-tangyizhou@huawei.com
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
2022-03-16 15:03:24 -06:00
Huang Ying
3624ba7b5e sched/numa-balancing: Move some document to make it consistent with the code
After commit 8a99b6833c ("sched: Move SCHED_DEBUG sysctl to
debugfs"), some NUMA balancing sysctls enclosed with SCHED_DEBUG has
been moved to debugfs.  This patch move the document for these
sysctls from

  Documentation/admin-guide/sysctl/kernel.rst

to

  Documentation/scheduler/sched-debug.rst

to make the document consistent with the code.

Signed-off-by: "Huang, Ying" <ying.huang@intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Valentin Schneider <valentin.schneider@arm.com>
Acked-by: Mel Gorman <mgorman@techsingularity.net>
Link: https://lkml.kernel.org/r/20220210052514.3038279-1-ying.huang@intel.com
2022-02-11 23:30:08 +01:00
Tang Yizhou
5dbbc145d2 docs: scheduler: Fix outdated parameter of rebalance_domains
According to the function prototype of rebalance_domains(), its first
parameter is *rq* and the document need to be updated.

Signed-off-by: Tang Yizhou <tangyizhou@huawei.com>
Link: https://lore.kernel.org/r/20211221031818.23186-1-tangyizhou@huawei.com
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
2022-02-01 16:29:25 -07:00
Yanteng Si
ce881fc06d docs/scheduler: fix typo and warning in sched-bwc
a) since d73df887b6 ("sched/fair: Add document for burstable CFS bandwidth")
[cpu.cfs_quota_us: the total available run-time within a period (in] shoud be removed,
let's delete it.

b) Add a period.

c) fix a build warning:

   linux-next/Documentation/scheduler/sched-bwc.rst:243: WARNING: Inline emphasis
   start-string without end-string.

Signed-off-by: Yanteng Si <siyanteng@loongson.cn>
Reviewed-by: Alex Shi <alexs@kernel.org>
Link: https://lore.kernel.org/r/163a4dde20b8c4b68d668977a668e281d18fcf92.1638517064.git.siyanteng@loongson.cn
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
2021-12-06 12:15:49 -07:00
Huaixin Chang
d73df887b6 sched/fair: Add document for burstable CFS bandwidth
Basic description of usage and effect for CFS Bandwidth Control Burst.

Co-developed-by: Shanpei Chen <shanpeic@linux.alibaba.com>
Signed-off-by: Shanpei Chen <shanpeic@linux.alibaba.com>
Co-developed-by: Tianchen Ding <dtcccc@linux.alibaba.com>
Signed-off-by: Tianchen Ding <dtcccc@linux.alibaba.com>
Signed-off-by: Huaixin Chang <changhuaixin@linux.alibaba.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Daniel Jordan <daniel.m.jordan@oracle.com>
Acked-by: Tejun Heo <tj@kernel.org>
Link: https://lore.kernel.org/r/20210830032215.16302-3-changhuaixin@linux.alibaba.com
2021-10-05 15:51:41 +02:00
Linus Torvalds
233a806b00 This was a reasonably active cycle for documentation; this pull includes:
- Some kernel-doc cleanups.  That script is still regex onslaught from
    hell, but it has gotten a little better.
 
  - Improvements to the checkpatch docs, which are also used by the tool
    itself.
 
  - A major update to the pathname lookup documentation.
 
  - Elimination of :doc: markup, since our automarkup magic can create
    references from filenames without all the extra noise.
 
  - The flurry of Chinese translation activity continues.
 
 Plus, of course, the usual collection of updates, typo fixes, and warning
 fixes.
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Merge tag 'docs-5.14' of git://git.lwn.net/linux

Pull documentation updates from Jonathan Corbet:
 "This was a reasonably active cycle for documentation; this includes:

   - Some kernel-doc cleanups. That script is still regex onslaught from
     hell, but it has gotten a little better.

   - Improvements to the checkpatch docs, which are also used by the
     tool itself.

   - A major update to the pathname lookup documentation.

   - Elimination of :doc: markup, since our automarkup magic can create
     references from filenames without all the extra noise.

   - The flurry of Chinese translation activity continues.

  Plus, of course, the usual collection of updates, typo fixes, and
  warning fixes"

* tag 'docs-5.14' of git://git.lwn.net/linux: (115 commits)
  docs: path-lookup: use bare function() rather than literals
  docs: path-lookup: update symlink description
  docs: path-lookup: update get_link() ->follow_link description
  docs: path-lookup: update WALK_GET, WALK_PUT desc
  docs: path-lookup: no get_link()
  docs: path-lookup: update i_op->put_link and cookie description
  docs: path-lookup: i_op->follow_link replaced with i_op->get_link
  docs: path-lookup: Add macro name to symlink limit description
  docs: path-lookup: remove filename_mountpoint
  docs: path-lookup: update do_last() part
  docs: path-lookup: update path_mountpoint() part
  docs: path-lookup: update path_to_nameidata() part
  docs: path-lookup: update follow_managed() part
  docs: Makefile: Use CONFIG_SHELL not SHELL
  docs: Take a little noise out of the build process
  docs: x86: avoid using ReST :doc:`foo` markup
  docs: virt: kvm: s390-pv-boot.rst: avoid using ReST :doc:`foo` markup
  docs: userspace-api: landlock.rst: avoid using ReST :doc:`foo` markup
  docs: trace: ftrace.rst: avoid using ReST :doc:`foo` markup
  docs: trace: coresight: coresight.rst: avoid using ReST :doc:`foo` markup
  ...
2021-06-28 16:53:05 -07:00
Beata Michalska
adf3c31e18 sched/doc: Update the CPU capacity asymmetry bits
Update the documentation bits referring to capacity aware scheduling
with regards to newly introduced SD_ASYM_CPUCAPACITY_FULL sched_domain
flag.

Signed-off-by: Beata Michalska <beata.michalska@arm.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Valentin Schneider <valentin.schneider@arm.com>
Reviewed-by: Dietmar Eggemann <dietmar.eggemann@arm.com>
Link: https://lore.kernel.org/r/20210603140627.8409-4-beata.michalska@arm.com
2021-06-24 09:07:51 +02:00
Mauro Carvalho Chehab
716c9d9403 docs: sched-bwc.rst: fix a typo on a doc name
cgroupv2.rst -> cgroup-v2.rst

Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
Link: https://lore.kernel.org/r/1dc0203bd7df375ef45832f0c88566e22c4138ff.1621413933.git.mchehab+huawei@kernel.org
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
2021-05-20 13:44:13 -06:00
Chun-Hung Tseng
35f1fceaa2 Documentation: scheduler: fixed 2 typos in sched-nice-design.rst
This patch fixed 2 spelling errors in the documentation.

Signed-off-by: Chun-Hung Tseng <henrybear327@gmail.com>
Link: https://lore.kernel.org/r/20210516105955.120651-1-henrybear327@gmail.com
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
2021-05-17 12:42:59 -06:00
Barry Song
19987fdad5 sched,doc: sched_debug_verbose cmdline should be sched_verbose
The cmdline should include sched_verbose but not sched_debug_verbose
as sched_debug_verbose is only the variant name in code.

Fixes: 9406415f46 ("sched/debug: Rename the sched_debug parameter to sched_verbose")
Signed-off-by: Barry Song <song.bao.hua@hisilicon.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Valentin Schneider <valentin.schneider@arm.com>
Link: https://lkml.kernel.org/r/20210504105344.31344-1-song.bao.hua@hisilicon.com
2021-05-06 15:33:26 +02:00
Peter Zijlstra
9406415f46 sched/debug: Rename the sched_debug parameter to sched_verbose
CONFIG_SCHED_DEBUG is the build-time Kconfig knob, the boot param
sched_debug and the /debug/sched/debug_enabled knobs control the
sched_debug_enabled variable, but what they really do is make
SCHED_DEBUG more verbose, so rename the lot.

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
2021-04-17 13:22:44 +02:00
Linus Torvalds
0e63a5c6ba It has been a relatively quiet cycle in docsland.
- As promised, the minimum Sphinx version to build the docs is now 1.7,
    and we have dropped support for Python 2 entirely.  That allowed the
    removal of a bunch of compatibility code.
 
  - A set of treewide warning fixups from Mauro that I applied after it
    became clear nobody else was going to deal with them.
 
  - The automarkup mechanism can now create cross-references from relative
    paths to RST files.
 
  - More translations, typo fixes, and warning fixes.
 
 No conflicts with any other tree as far as I know.
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Merge tag 'docs-5.12' of git://git.lwn.net/linux

Pull documentation updates from Jonathan Corbet:
 "It has been a relatively quiet cycle in docsland.

   - As promised, the minimum Sphinx version to build the docs is now
     1.7, and we have dropped support for Python 2 entirely. That
     allowed the removal of a bunch of compatibility code.

   - A set of treewide warning fixups from Mauro that I applied after it
     became clear nobody else was going to deal with them.

   - The automarkup mechanism can now create cross-references from
     relative paths to RST files.

   - More translations, typo fixes, and warning fixes"

* tag 'docs-5.12' of git://git.lwn.net/linux: (75 commits)
  docs: kernel-hacking: be more civil
  docs: Remove the Microsoft rhetoric
  Documentation/admin-guide: kernel-parameters: Update nohlt section
  doc/admin-guide: fix spelling mistake: "perfomance" -> "performance"
  docs: Document cross-referencing using relative path
  docs: Enable usage of relative paths to docs on automarkup
  docs: thermal: fix spelling mistakes
  Documentation: admin-guide: Update kvm/xen config option
  docs: Make syscalls' helpers naming consistent
  coding-style.rst: Avoid comma statements
  Documentation: /proc/loadavg: add 3 more field descriptions
  Documentation/submitting-patches: Add blurb about backtraces in commit messages
  Docs: drop Python 2 support
  Move our minimum Sphinx version to 1.7
  Documentation: input: define ABS_PRESSURE/ABS_MT_PRESSURE resolution as grams
  scripts/kernel-doc: add internal hyperlink to DOC: sections
  Update Documentation/admin-guide/sysctl/fs.rst
  docs: Update DTB format references
  docs: zh_CN: add iio index.rst translation
  docs/zh_CN: add iio ep93xx_adc.rst translation
  ...
2021-02-22 10:57:46 -08:00
Kir Kolyshkin
e5ba9ea634 docs/scheduler/sched-bwc: note/link cgroup v2
Signed-off-by: Kir Kolyshkin <kolyshkin@gmail.com>
Acked-by: Tejun Heo <tj@kernel.org>
Link: https://lore.kernel.org/r/20210120001824.385168-6-kolyshkin@gmail.com
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
2021-01-21 11:41:03 -07:00
Kir Kolyshkin
6c57c12d0f docs/scheduler/sched-bwc: fix note rendering
Signed-off-by: Kir Kolyshkin <kolyshkin@gmail.com>
Acked-by: Tejun Heo <tj@kernel.org>
Link: https://lore.kernel.org/r/20210120001824.385168-4-kolyshkin@gmail.com
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
2021-01-21 11:40:21 -07:00
Kir Kolyshkin
f1779d13ed docs/scheduler/sched-design-CFS: formatting fix
Fix the rendering of the paragraph. Before the fix, the first line is
rendered in bold (I'm not quite sure why) and is also separated from the
rest of the paragraph, which is rendered with an indent.

Signed-off-by: Kir Kolyshkin <kolyshkin@gmail.com>
Acked-by: Tejun Heo <tj@kernel.org>
Link: https://lore.kernel.org/r/20210120001824.385168-3-kolyshkin@gmail.com
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
2021-01-21 11:40:21 -07:00
Kir Kolyshkin
7ebc7dc871 docs/scheduler/sched-bwc: formatting fix
Since commit d6a3b24762 these three lines are merged into one by the
RST processor, making it hard to read. Use bullet points to separate
the entries, like it's done in other similar places.

Signed-off-by: Kir Kolyshkin <kolyshkin@gmail.com>
Acked-by: Tejun Heo <tj@kernel.org>
Link: https://lore.kernel.org/r/20210120001824.385168-2-kolyshkin@gmail.com
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
2021-01-21 11:40:21 -07:00
Peter Zijlstra
0301925dd0 sched: Add schedutil overview
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Morten Rasmussen <morten.rasmussen@arm.com>
Link: https://lkml.kernel.org/r/20201218103258.GA3040@hirez.programming.kicks-ass.net
2021-01-14 11:20:10 +01:00
Joe Perches
05a5f51ca5 Documentation: Replace lkml.org links with lore
Replace the lkml.org links with lore to better use a single source
that's more likely to stay available long-term.

Done by bash script:

cvt_lkml_to_lore ()
{
    tmpfile=$(mktemp ./.cvt_links.XXXXXXX)

    header=$(echo $1 | sed 's@/lkml/@/lkml/headers/@')

    wget -qO - $header > $tmpfile
    if [[ $? == 0 ]] ; then
	link=$(grep -i '^Message-Id:' $tmpfile | head -1 | \
		   sed -r -e 's/^\s*Message-Id:\s*<\s*//' -e  's/\s*>\s*$//' -e 's@^@https://lore.kernel.org/r/@')
	#    echo "testlink: $link"
	if [ -n "$link" ] ; then
	    wget -qO - $link > /dev/null
	    if [[ $? == 0 ]] ; then
		echo $link
	    fi
	fi
    fi

    rm -f $tmpfile
}

git grep -P -o "\bhttps?://(?:www.)?lkml.org/lkml[\/\w]+" $@ |
    while read line ; do
	echo $line
	file=$(echo $line | cut -f1 -d':')
	link=$(echo $line | cut -f2- -d':')
	newlink=$(cvt_lkml_to_lore $link)
	if [[ -n "$newlink" ]] ; then
	    sed -i -e "s#\b$link\b#$newlink#" $file
	fi
    done

Link: https://lore.kernel.org/patchwork/patch/1265849/#1462688
Signed-off-by: Joe Perches <joe@perches.com>
Link: https://lore.kernel.org/r/77cdb7f32cfb087955bfc3600b86c40bed5d4104.camel@perches.com
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
2021-01-11 12:47:38 -07:00
Linus Torvalds
b4ec805464 Power management updates for 5.11-rc1
- Use local_clock() instead of jiffies in the cpufreq statistics to
    improve accuracy (Viresh Kumar).
 
  - Fix up OPP usage in the cpufreq-dt and qcom-cpufreq-nvmem cpufreq
    drivers (Viresh Kumar).
 
  - Clean up the cpufreq core, the intel_pstate driver and the
    schedutil cpufreq governor (Rafael Wysocki).
 
  - Fix up error code paths in the sti-cpufreq and mediatek cpufreq
    drivers (Yangtao Li, Qinglang Miao).
 
  - Fix cpufreq_online() to return error codes instead of success (0)
    in all cases when it fails (Wang ShaoBo).
 
  - Add mt8167 support to the mediatek cpufreq driver and blacklist
    mt8516 in the cpufreq-dt-platdev driver (Fabien Parent).
 
  - Modify the tegra194 cpufreq driver to always return values from
    the frequency table as the current frequency and clean up that
    driver (Sumit Gupta, Jon Hunter).
 
  - Modify the arm_scmi cpufreq driver to allow it to discover the
    power scale present in the performance protocol and provide this
    information to the Energy Model (Lukasz Luba).
 
  - Add missing MODULE_DEVICE_TABLE to several cpufreq drivers (Pali
    Rohár).
 
  - Clean up the CPPC cpufreq driver (Ionela Voinescu).
 
  - Fix NVMEM_IMX_OCOTP dependency in the imx cpufreq driver (Arnd
    Bergmann).
 
  - Rework the poling interval selection for the polling state in
    cpuidle (Mel Gorman).
 
  - Enable suspend-to-idle for PSCI OSI mode in the PSCI cpuidle
    driver (Ulf Hansson).
 
  - Modify the OPP framework to support empty (node-less) OPP tables
    in DT for passing dependency information (Nicola Mazzucato).
 
  - Fix potential lockdep issue in the OPP core and clean up the OPP
    core (Viresh Kumar).
 
  - Modify dev_pm_opp_put_regulators() to accept a NULL argument and
    update its users accordingly (Viresh Kumar).
 
  - Add frequency changes tracepoint to devfreq (Matthias Kaehlcke).
 
  - Add support for governor feature flags to devfreq, make devfreq
    sysfs file permissions depend on the governor and clean up the
    devfreq core (Chanwoo Choi).
 
  - Clean up the tegra20 devfreq driver and deprecate it to allow
    another driver based on EMC_STAT to be used instead of it (Dmitry
    Osipenko).
 
  - Add interconnect support to the tegra30 devfreq driver, allow it
    to take the interconnect and OPP information from DT and clean it
    up ((Dmitry Osipenko).
 
  - Add interconnect support to the exynos-bus devfreq driver along
    with interconnect properties documentation (Sylwester Nawrocki).
 
  - Add suport for AMD Fam17h and Fam19h processors to the RAPL power
    capping driver (Victor Ding, Kim Phillips).
 
  - Fix handling of overly long constraint names in the powercap
    framework (Lukasz Luba).
 
  - Fix the wakeup configuration handling for bridges in the ACPI
    device power management core (Rafael Wysocki).
 
  - Add support for using an abstract scale for power units in the
    Energy Model (EM) and document it (Lukasz Luba).
 
  - Add em_cpu_energy() micro-optimization to the EM (Pavankumar
    Kondeti).
 
  - Modify the generic power domains (genpd) framwework to support
    suspend-to-idle (Ulf Hansson).
 
  - Fix creation of debugfs nodes in genpd (Thierry Strudel).
 
  - Clean up genpd (Lina Iyer).
 
  - Clean up the core system-wide suspend code and make it print
    driver flags for devices with debug enabled (Alex Shi, Patrice
    Chotard, Chen Yu).
 
  - Modify the ACPI system reboot code to make it prepare for system
    power off to avoid confusing the platform firmware (Kai-Heng Feng).
 
  - Update the pm-graph (multiple changes, mostly usability-related)
    and cpupower (online and offline CPU information support) PM
    utilities (Todd Brandt, Brahadambal Srinivasan).
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Merge tag 'pm-5.11-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm

Pull power management updates from Rafael Wysocki:
 "These update cpufreq (core and drivers), cpuidle (polling state
  implementation and the PSCI driver), the OPP (operating performance
  points) framework, devfreq (core and drivers), the power capping RAPL
  (Running Average Power Limit) driver, the Energy Model support, the
  generic power domains (genpd) framework, the ACPI device power
  management, the core system-wide suspend code and power management
  utilities.

  Specifics:

   - Use local_clock() instead of jiffies in the cpufreq statistics to
     improve accuracy (Viresh Kumar).

   - Fix up OPP usage in the cpufreq-dt and qcom-cpufreq-nvmem cpufreq
     drivers (Viresh Kumar).

   - Clean up the cpufreq core, the intel_pstate driver and the
     schedutil cpufreq governor (Rafael Wysocki).

   - Fix up error code paths in the sti-cpufreq and mediatek cpufreq
     drivers (Yangtao Li, Qinglang Miao).

   - Fix cpufreq_online() to return error codes instead of success (0)
     in all cases when it fails (Wang ShaoBo).

   - Add mt8167 support to the mediatek cpufreq driver and blacklist
     mt8516 in the cpufreq-dt-platdev driver (Fabien Parent).

   - Modify the tegra194 cpufreq driver to always return values from the
     frequency table as the current frequency and clean up that driver
     (Sumit Gupta, Jon Hunter).

   - Modify the arm_scmi cpufreq driver to allow it to discover the
     power scale present in the performance protocol and provide this
     information to the Energy Model (Lukasz Luba).

   - Add missing MODULE_DEVICE_TABLE to several cpufreq drivers (Pali
     Rohár).

   - Clean up the CPPC cpufreq driver (Ionela Voinescu).

   - Fix NVMEM_IMX_OCOTP dependency in the imx cpufreq driver (Arnd
     Bergmann).

   - Rework the poling interval selection for the polling state in
     cpuidle (Mel Gorman).

   - Enable suspend-to-idle for PSCI OSI mode in the PSCI cpuidle driver
     (Ulf Hansson).

   - Modify the OPP framework to support empty (node-less) OPP tables in
     DT for passing dependency information (Nicola Mazzucato).

   - Fix potential lockdep issue in the OPP core and clean up the OPP
     core (Viresh Kumar).

   - Modify dev_pm_opp_put_regulators() to accept a NULL argument and
     update its users accordingly (Viresh Kumar).

   - Add frequency changes tracepoint to devfreq (Matthias Kaehlcke).

   - Add support for governor feature flags to devfreq, make devfreq
     sysfs file permissions depend on the governor and clean up the
     devfreq core (Chanwoo Choi).

   - Clean up the tegra20 devfreq driver and deprecate it to allow
     another driver based on EMC_STAT to be used instead of it (Dmitry
     Osipenko).

   - Add interconnect support to the tegra30 devfreq driver, allow it to
     take the interconnect and OPP information from DT and clean it up
     (Dmitry Osipenko).

   - Add interconnect support to the exynos-bus devfreq driver along
     with interconnect properties documentation (Sylwester Nawrocki).

   - Add suport for AMD Fam17h and Fam19h processors to the RAPL power
     capping driver (Victor Ding, Kim Phillips).

   - Fix handling of overly long constraint names in the powercap
     framework (Lukasz Luba).

   - Fix the wakeup configuration handling for bridges in the ACPI
     device power management core (Rafael Wysocki).

   - Add support for using an abstract scale for power units in the
     Energy Model (EM) and document it (Lukasz Luba).

   - Add em_cpu_energy() micro-optimization to the EM (Pavankumar
     Kondeti).

   - Modify the generic power domains (genpd) framwework to support
     suspend-to-idle (Ulf Hansson).

   - Fix creation of debugfs nodes in genpd (Thierry Strudel).

   - Clean up genpd (Lina Iyer).

   - Clean up the core system-wide suspend code and make it print driver
     flags for devices with debug enabled (Alex Shi, Patrice Chotard,
     Chen Yu).

   - Modify the ACPI system reboot code to make it prepare for system
     power off to avoid confusing the platform firmware (Kai-Heng Feng).

   - Update the pm-graph (multiple changes, mostly usability-related)
     and cpupower (online and offline CPU information support) PM
     utilities (Todd Brandt, Brahadambal Srinivasan)"

* tag 'pm-5.11-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm: (86 commits)
  cpufreq: Fix cpufreq_online() return value on errors
  cpufreq: Fix up several kerneldoc comments
  cpufreq: stats: Use local_clock() instead of jiffies
  cpufreq: schedutil: Simplify sugov_update_next_freq()
  cpufreq: intel_pstate: Simplify intel_cpufreq_update_pstate()
  PM: domains: create debugfs nodes when adding power domains
  opp: of: Allow empty opp-table with opp-shared
  dt-bindings: opp: Allow empty OPP tables
  media: venus: dev_pm_opp_put_*() accepts NULL argument
  drm/panfrost: dev_pm_opp_put_*() accepts NULL argument
  drm/lima: dev_pm_opp_put_*() accepts NULL argument
  PM / devfreq: exynos: dev_pm_opp_put_*() accepts NULL argument
  cpufreq: qcom-cpufreq-nvmem: dev_pm_opp_put_*() accepts NULL argument
  cpufreq: dt: dev_pm_opp_put_regulators() accepts NULL argument
  opp: Allow dev_pm_opp_put_*() APIs to accept NULL opp_table
  opp: Don't create an OPP table from dev_pm_opp_get_opp_table()
  cpufreq: dt: Don't (ab)use dev_pm_opp_get_opp_table() to create OPP table
  opp: Reduce the size of critical section in _opp_kref_release()
  PM / EM: Micro optimization in em_cpu_energy
  cpufreq: arm_scmi: Discover the power scale in performance protocol
  ...
2020-12-15 16:30:31 -08:00
Barry Song
9032dc2115 Documentation: scheduler: fix information on arch SD flags, sched_domain and sched_debug
This document seems to be out of date for many, many years. Even it has
misspelled from the first day.
ARCH_HASH_SCHED_TUNE should be ARCH_HAS_SCHED_TUNE
ARCH_HASH_SCHED_DOMAIN should be ARCH_HAS_SCHED_DOMAIN

Since v2.6.14, kernel completely deleted the relevant code and even
arch_init_sched_domains() was deleted.

Right now, kernel is asking architectures to call set_sched_topology() to
override the default sched domains.

On the other hand, to print the schedule debug information, users need to
set sched_debug cmdline or enable it by sysfs entry. So this patch also
adds the description for sched_debug.

Signed-off-by: Barry Song <song.bao.hua@hisilicon.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Valentin Schneider <valentin.schneider@arm.com>
Link: https://lkml.kernel.org/r/20201113115018.1628-1-song.bao.hua@hisilicon.com
2020-11-19 11:25:46 +01:00
Lukasz Luba
5a64f77569 PM: EM: Clarify abstract scale usage for power values in Energy Model
The Energy Model (EM) can store power values in milli-Watts or in abstract
scale. This might cause issues in the subsystems which use the EM for
estimating the device power, such as:

 - mixing of different scales in a subsystem which uses multiple
   (cooling) devices (e.g. thermal Intelligent Power Allocation (IPA))

 - assuming that energy [milli-Joules] can be derived from the EM power
   values which might not be possible since the power scale doesn't have
   to be in milli-Watts

To avoid misconfiguration add the requisite documentation to the EM and
related subsystems: EAS and IPA.

Signed-off-by: Lukasz Luba <lukasz.luba@arm.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2020-11-10 20:29:28 +01:00
Mauro Carvalho Chehab
e4e29e78c0 docs: scheduler: fix the directory name on two files
The name of the directory where the schedule docs are
stored are wrong on those files.

Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
Reviewed-by: Valentin Schneider <valentin.schneider@arm.com>
Link: https://lore.kernel.org/r/a32c2bba17aa69dc18670b7de1a3a35bfa1e1f88.1599660067.git.mchehab+huawei@kernel.org
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
2020-09-10 10:45:45 -06:00
Valentin Schneider
949bcb8135 sched/doc: Factorize bits between sched-energy.rst & sched-capacity.rst
Documentation/scheduler/sched-capacity.rst ought to be the canonical place
to blabber about SD_ASYM_CPUCAPACITY, so remove its explanation from
sched-energy.rst and point to sched-capacity.rst instead.

Signed-off-by: Valentin Schneider <valentin.schneider@arm.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Link: https://lore.kernel.org/r/20200731192016.7484-4-valentin.schneider@arm.com
2020-08-01 09:19:43 +02:00
Valentin Schneider
65065fd70b sched/doc: Document capacity aware scheduling
Add some documentation detailing the concepts, requirements and
implementation of capacity aware scheduling across the different scheduler
classes.

Signed-off-by: Valentin Schneider <valentin.schneider@arm.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Link: https://lore.kernel.org/r/20200731192016.7484-3-valentin.schneider@arm.com
2020-08-01 09:19:43 +02:00
Adrian Freund
7b9121040d Documentation: scheduler: fix outdated information on sched groups
The documentation claims that two sched groups must not overlap. This is
no longer true, as overlapping sched groups are used on NUMA systems.
This change has been introduced by commit e3589f6c81 and was
documented by an in-code comment in commit 35a566e6e8.

Signed-off-by: Adrian Freund <adrian@freund.io>
Link: https://lore.kernel.org/r/20200407130525.76663-1-adrian@freund.io
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
2020-04-21 13:38:27 -06:00
Andre Azevedo
d41abfd7ae Documentation/scheduler: fix links in sched-stats
The rain.com domain recently moved to pdxhosts.com, making the scheduler
documentation point to broken links. Fix the links in the scheduler
documentation.

CC: Rick Lindsley <ricklind@linux.vnet.ibm.com>
Signed-off-by: Andre Azevedo <andre.azevedo@gmail.com>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
2019-10-29 04:35:41 -06:00
Dave Chiluk
de53fd7aed sched/fair: Fix low cpu usage with high throttling by removing expiration of cpu-local slices
It has been observed, that highly-threaded, non-cpu-bound applications
running under cpu.cfs_quota_us constraints can hit a high percentage of
periods throttled while simultaneously not consuming the allocated
amount of quota. This use case is typical of user-interactive non-cpu
bound applications, such as those running in kubernetes or mesos when
run on multiple cpu cores.

This has been root caused to cpu-local run queue being allocated per cpu
bandwidth slices, and then not fully using that slice within the period.
At which point the slice and quota expires. This expiration of unused
slice results in applications not being able to utilize the quota for
which they are allocated.

The non-expiration of per-cpu slices was recently fixed by
'commit 512ac999d2 ("sched/fair: Fix bandwidth timer clock drift
condition")'. Prior to that it appears that this had been broken since
at least 'commit 51f2176d74 ("sched/fair: Fix unlocked reads of some
cfs_b->quota/period")' which was introduced in v3.16-rc1 in 2014. That
added the following conditional which resulted in slices never being
expired.

if (cfs_rq->runtime_expires != cfs_b->runtime_expires) {
	/* extend local deadline, drift is bounded above by 2 ticks */
	cfs_rq->runtime_expires += TICK_NSEC;

Because this was broken for nearly 5 years, and has recently been fixed
and is now being noticed by many users running kubernetes
(https://github.com/kubernetes/kubernetes/issues/67577) it is my opinion
that the mechanisms around expiring runtime should be removed
altogether.

This allows quota already allocated to per-cpu run-queues to live longer
than the period boundary. This allows threads on runqueues that do not
use much CPU to continue to use their remaining slice over a longer
period of time than cpu.cfs_period_us. However, this helps prevent the
above condition of hitting throttling while also not fully utilizing
your cpu quota.

This theoretically allows a machine to use slightly more than its
allotted quota in some periods. This overflow would be bounded by the
remaining quota left on each per-cpu runqueueu. This is typically no
more than min_cfs_rq_runtime=1ms per cpu. For CPU bound tasks this will
change nothing, as they should theoretically fully utilize all of their
quota in each period. For user-interactive tasks as described above this
provides a much better user/application experience as their cpu
utilization will more closely match the amount they requested when they
hit throttling. This means that cpu limits no longer strictly apply per
period for non-cpu bound applications, but that they are still accurate
over longer timeframes.

This greatly improves performance of high-thread-count, non-cpu bound
applications with low cfs_quota_us allocation on high-core-count
machines. In the case of an artificial testcase (10ms/100ms of quota on
80 CPU machine), this commit resulted in almost 30x performance
improvement, while still maintaining correct cpu quota restrictions.
That testcase is available at https://github.com/indeedeng/fibtest.

Fixes: 512ac999d2 ("sched/fair: Fix bandwidth timer clock drift condition")
Signed-off-by: Dave Chiluk <chiluk+linux@indeed.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Phil Auld <pauld@redhat.com>
Reviewed-by: Ben Segall <bsegall@google.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: John Hammond <jhammond@indeed.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Kyle Anderson <kwa@yelp.com>
Cc: Gabriel Munos <gmunoz@netflix.com>
Cc: Peter Oskolkov <posk@posk.io>
Cc: Cong Wang <xiyou.wangcong@gmail.com>
Cc: Brendan Gregg <bgregg@netflix.com>
Link: https://lkml.kernel.org/r/1563900266-19734-2-git-send-email-chiluk+linux@indeed.com
2019-08-08 09:09:30 +02:00