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* sched/topology: Remove the EM_MAX_COMPLEXITY limitPierre Gondois2023-10-091-26/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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: b68a4c0dba3b1 ("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: 390031e4c309 ("sched/fair: Introduce an energy estimation helper function") ... but the complexity of EAS was reduced in: eb92692b2544d ("sched/fair: Speed-up energy-aware wake-ups") ... and find_energy_efficient_cpu() (feec) algorithm was updated in: 3e8c6c9aac42 ("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: b68a4c0dba3b1 ("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
* Documentation: Fix typosBjorn Helgaas2023-08-181-2/+2
| | | | | | | | 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>
* sched/doc: Update the CPU capacity asymmetry bitsBeata Michalska2021-06-241-1/+1
| | | | | | | | | | | | 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
* PM: EM: Clarify abstract scale usage for power values in Energy ModelLukasz Luba2020-11-101-0/+5
| | | | | | | | | | | | | | | | | | | 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>
* docs: scheduler: fix the directory name on two filesMauro Carvalho Chehab2020-09-101-1/+1
| | | | | | | | | | 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>
* sched/doc: Factorize bits between sched-energy.rst & sched-capacity.rstValentin Schneider2020-08-011-10/+2
| | | | | | | | | | 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
* Merge tag 'pci-v5.3-changes' of ↵Linus Torvalds2019-07-151-3/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/helgaas/pci Pull PCI updates from Bjorn Helgaas: "Enumeration changes: - Evaluate PCI Boot Configuration _DSM to learn if firmware wants us to preserve its resource assignments (Benjamin Herrenschmidt) - Simplify resource distribution (Nicholas Johnson) - Decode 32 GT/s link speed (Gustavo Pimentel) Virtualization: - Fix incorrect caching of VF config space size (Alex Williamson) - Fix VF driver probing sysfs knobs (Alex Williamson) Peer-to-peer DMA: - Fix dma_virt_ops check (Logan Gunthorpe) Altera host bridge driver: - Allow building as module (Ley Foon Tan) Armada 8K host bridge driver: - add PHYs support (Miquel Raynal) DesignWare host bridge driver: - Export APIs to support removable loadable module (Vidya Sagar) - Enable Relaxed Ordering erratum workaround only on Tegra20 & Tegra30 (Vidya Sagar) Hyper-V host bridge driver: - Fix use-after-free in eject (Dexuan Cui) Mobiveil host bridge driver: - Clean up and fix many issues, including non-identify mapped windows, 64-bit windows, multi-MSI, class code, INTx clearing (Hou Zhiqiang) Qualcomm host bridge driver: - Use clk bulk API for 2.4.0 controllers (Bjorn Andersson) - Add QCS404 support (Bjorn Andersson) - Assert PERST for at least 100ms (Niklas Cassel) R-Car host bridge driver: - Add r8a774a1 DT support (Biju Das) Tegra host bridge driver: - Add support for Gen2, opportunistic UpdateFC and ACK (PCIe protocol details) AER, GPIO-based PERST# (Manikanta Maddireddy) - Fix many issues, including power-on failure cases, interrupt masking in suspend, UPHY settings, AFI dynamic clock gating, pending DLL transactions (Manikanta Maddireddy) Xilinx host bridge driver: - Fix NWL Multi-MSI programming (Bharat Kumar Gogada) Endpoint support: - Fix 64bit BAR support (Alan Mikhak) - Fix pcitest build issues (Alan Mikhak, Andy Shevchenko) Bug fixes: - Fix NVIDIA GPU multi-function power dependencies (Abhishek Sahu) - Fix NVIDIA GPU HDA enablement issue (Lukas Wunner) - Ignore lockdep for sysfs "remove" (Marek Vasut) Misc: - Convert docs to reST (Changbin Du, Mauro Carvalho Chehab)" * tag 'pci-v5.3-changes' of git://git.kernel.org/pub/scm/linux/kernel/git/helgaas/pci: (107 commits) PCI: Enable NVIDIA HDA controllers tools: PCI: Fix installation when `make tools/pci_install` PCI: dwc: pci-dra7xx: Fix compilation when !CONFIG_GPIOLIB PCI: Fix typos and whitespace errors PCI: mobiveil: Fix INTx interrupt clearing in mobiveil_pcie_isr() PCI: mobiveil: Fix infinite-loop in the INTx handling function PCI: mobiveil: Move PCIe PIO enablement out of inbound window routine PCI: mobiveil: Add upper 32-bit PCI base address setup in inbound window PCI: mobiveil: Add upper 32-bit CPU base address setup in outbound window PCI: mobiveil: Mask out hardcoded bits in inbound/outbound windows setup PCI: mobiveil: Clear the control fields before updating it PCI: mobiveil: Add configured inbound windows counter PCI: mobiveil: Fix the valid check for inbound and outbound windows PCI: mobiveil: Clean-up program_{ib/ob}_windows() PCI: mobiveil: Remove an unnecessary return value check PCI: mobiveil: Fix error return values PCI: mobiveil: Refactor the MEM/IO outbound window initialization PCI: mobiveil: Make some register updates more readable PCI: mobiveil: Reformat the code for readability dt-bindings: PCI: mobiveil: Change gpio_slave and apb_csr to optional ...
* docs: scheduler: convert docs to ReST and rename to *.rstMauro Carvalho Chehab2019-06-141-0/+430
In order to prepare to add them to the Kernel API book, convert the files to ReST format. The conversion is actually: - add blank lines and identation in order to identify paragraphs; - fix tables markups; - add some lists markups; - mark literal blocks; - adjust title markups. At its new index.rst, let's add a :orphan: while this is not linked to the main index.rst file, in order to avoid build warnings. Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org> Signed-off-by: Jonathan Corbet <corbet@lwn.net>