kernel: mvebu: enable tickless idle#9139
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igorpecovnik merged 1 commit intoarmbian:mainfrom Dec 29, 2025
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Caution Review failedThe pull request is closed. 📝 WalkthroughWalkthroughRemoved periodic HZ and enabled NO_HZ options; switched CPU idle governor from LADDER to MENU across mvebu kernel defconfig files. Changes
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Nothing obviously wrong. Would want to see the board maintainers pipe in here to see if there's any concerns or history here. |
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No concerns. If its good for WRT ...
Switch to NO_HZ_IDLE for energy saving. Also enable Menu cpuidle governor for tickless systems. Signed-off-by: Rosen Penev <rosenp@gmail.com> Signed-off-by: Igor Pecovnik <igor@armbian.com>
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⚠️ Outside diff range comments (1)
config/kernel/linux-mvebu-current.config (1)
66-69: Change CPU idle governor from LADDER to MENU for consistency with tickless idle configuration.The 32-bit config (
linux-mvebu-current.configline 67) hasCONFIG_CPU_IDLE_GOV_LADDER=ywhile the 64-bit variant (linux-mvebu64-current.configline 64) hasCONFIG_CPU_IDLE_GOV_MENU=y. Both configs haveCONFIG_NO_HZ_IDLE=yenabled (tickless idle), and the PR description states "Enable the Menu cpuidle governor for tickless systems." The MENU governor is recommended for tickless systems as it uses more sophisticated idle duration prediction. Additionally, the edge variants of both 32-bit and 64-bit configs already use MENU, indicating the intended direction.Update line 67 to
CONFIG_CPU_IDLE_GOV_MENU=yto align with the PR objectives and the 64-bit configuration.
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📒 Files selected for processing (4)
config/kernel/linux-mvebu-current.configconfig/kernel/linux-mvebu-edge.configconfig/kernel/linux-mvebu64-current.configconfig/kernel/linux-mvebu64-edge.config
🚧 Files skipped from review as they are similar to previous changes (2)
- config/kernel/linux-mvebu-edge.config
- config/kernel/linux-mvebu64-edge.config
🧰 Additional context used
🧠 Learnings (15)
📓 Common learnings
Learnt from: EvilOlaf
Repo: armbian/build PR: 0
File: :0-0
Timestamp: 2025-12-19T13:56:45.124Z
Learning: When reviewing kernel or u-boot version bump PRs in the Armbian build system, check if patches existed in previous kernel version directories (e.g., sunxi-6.12, sunxi-6.13) before describing them as new features. If a patch and the majority of its contents existed previously with no major functionality changes, focus the review on the actual changes: the version bump itself and patch compatibility adjustments. Don't describe existing patches being ported/maintained across versions as new features or drivers—this is misleading. The patches are existing code being re-aligned to work with the new upstream version.
Learnt from: tabrisnet
Repo: armbian/build PR: 8678
File: config/kernel/linux-sunxi64-current.config:94-94
Timestamp: 2025-09-27T21:50:15.915Z
Learning: When kernel config files are generated through Armbian's automated process (previous config → armbian-kernel.sh changes → make oldconfig → Armbian machinery processing), manual config file edits are not appropriate since they would be overwritten. Deprecated option handling should be implemented in the automated tooling instead.
Learnt from: igorpecovnik
Repo: armbian/build PR: 8849
File: config/boards/radxa-e54c.csc:14-28
Timestamp: 2025-11-02T20:49:56.719Z
Learning: In Armbian board configuration files (config/boards/*.conf, *.csc, etc.), do not use kernel_config_set, kernel_config_set_m, kernel_config_set_y, or custom_kernel_config__* functions to modify kernel configuration. Kernel configuration is associated with LINUXFAMILY/BOARDFAMILY, not individual BOARD. Board-specific kernel modifications cause inconsistency in kernel packages published to the apt repository because boards within a family share the same kernel packages. Kernel configuration changes must be made in the appropriate kernel config file (e.g., config/kernel/linux-*-*.config) or in family configuration files (config/sources/families/*.conf, *.inc) instead.
Learnt from: tabrisnet
Repo: armbian/build PR: 8678
File: config/kernel/linux-bcm2711-edge.config:859-861
Timestamp: 2025-09-27T21:47:58.020Z
Learning: In the Armbian build system, kernel configuration files in config/kernel/ are generated through an automated process: taking previous config → applying scripted changes from armbian-kernel.sh → running kernel's `make oldconfig` → processing by Armbian machinery back into config files. This automated process properly handles kernel configuration dependencies and reduces the likelihood of manual configuration errors.
Learnt from: tabrisnet
Repo: armbian/build PR: 8678
File: config/kernel/linux-sm8250-current.config:78-80
Timestamp: 2025-09-27T21:49:55.796Z
Learning: In the Armbian build system, kernel configuration files are generated through an automated process: taking previous config → applying scripted changes from armbian-kernel.sh → running kernel's `make oldconfig` → processing by Armbian machinery back into config files. This automated process properly handles kernel configuration dependencies and reduces the likelihood of manual configuration errors.
Learnt from: tabrisnet
Repo: armbian/build PR: 8678
File: config/kernel/linux-sm8250-edge.config:80-82
Timestamp: 2025-09-27T21:50:04.845Z
Learning: In the Armbian build system, kernel configuration files are generated through this automated process: taking previous config → applying scripted changes from armbian-kernel.sh → running kernel's `make oldconfig` → processing by Armbian machinery back into config files. This automated process properly handles kernel configuration dependencies and reduces the likelihood of manual configuration errors.
Learnt from: tabrisnet
Repo: armbian/build PR: 0
File: :0-0
Timestamp: 2025-08-30T04:13:16.457Z
Learning: Armbian kernel configuration files like linux-filogic-current.config are autogenerated overlays on top of arch defconfig. Comments added manually will be lost during future updates by maintainers, and explicit "CONFIG_OPTION is not set" statements aren't needed for mutually exclusive options since these are overlay configs that only specify changes from the base configuration.
Learnt from: EvilOlaf
Repo: armbian/build PR: 0
File: :0-0
Timestamp: 2025-08-02T05:46:10.664Z
Learning: In the Armbian build system, the KERNEL_CONFIGURE=yes switch is deprecated. The recommended approach for kernel configuration is now to use the `kernel-config` build command, which provides a more structured way to configure kernel options.
Learnt from: tabrisnet
Repo: armbian/build PR: 9136
File: lib/functions/compilation/armbian-kernel.sh:529-537
Timestamp: 2025-12-28T01:49:28.830Z
Learning: In lib/functions/compilation/armbian-kernel.sh's opts_m handling, checking .config (kernel defconfig) is problematic because savedefconfig elides options matching defconfig, making it impossible to distinguish overlay silence from defconfig agreement. The correct approach is to check only kernel_config_source_filename (the overlay) for explicit =y, otherwise default to =m, letting savedefconfig handle deduplication with defconfig automatically.
Learnt from: tabrisnet
Repo: armbian/build PR: 8661
File: lib/functions/compilation/armbian-kernel.sh:194-201
Timestamp: 2025-09-22T21:52:01.225Z
Learning: In lib/functions/compilation/armbian-kernel.sh, the kernel_config_modifying_hashes array is not universally required for all kernel configuration functions - some functions like armbian_kernel_config__netkit() operate without it, and adding entries with '=m' would be incorrect when the actual result might be '=y' for options already built-in.
Learnt from: tabrisnet
Repo: armbian/build PR: 8661
File: lib/functions/compilation/armbian-kernel.sh:194-201
Timestamp: 2025-09-22T21:52:01.225Z
Learning: In lib/functions/compilation/armbian-kernel.sh, the kernel_config_modifying_hashes array is not universally required for all kernel configuration functions - some functions like armbian_kernel_config__netkit() operate without it, and adding entries with '=m' would be incorrect when the actual result might be '=y' for options already built-in.
📚 Learning: 2025-08-30T04:13:16.457Z
Learnt from: tabrisnet
Repo: armbian/build PR: 0
File: :0-0
Timestamp: 2025-08-30T04:13:16.457Z
Learning: Armbian kernel configuration files like linux-filogic-current.config are autogenerated overlays on top of arch defconfig. Comments added manually will be lost during future updates by maintainers, and explicit "CONFIG_OPTION is not set" statements aren't needed for mutually exclusive options since these are overlay configs that only specify changes from the base configuration.
Applied to files:
config/kernel/linux-mvebu-current.configconfig/kernel/linux-mvebu64-current.config
📚 Learning: 2025-09-27T21:50:15.915Z
Learnt from: tabrisnet
Repo: armbian/build PR: 8678
File: config/kernel/linux-sunxi64-current.config:94-94
Timestamp: 2025-09-27T21:50:15.915Z
Learning: When kernel config files are generated through Armbian's automated process (previous config → armbian-kernel.sh changes → make oldconfig → Armbian machinery processing), manual config file edits are not appropriate since they would be overwritten. Deprecated option handling should be implemented in the automated tooling instead.
Applied to files:
config/kernel/linux-mvebu-current.configconfig/kernel/linux-mvebu64-current.config
📚 Learning: 2025-12-28T01:49:28.830Z
Learnt from: tabrisnet
Repo: armbian/build PR: 9136
File: lib/functions/compilation/armbian-kernel.sh:529-537
Timestamp: 2025-12-28T01:49:28.830Z
Learning: In lib/functions/compilation/armbian-kernel.sh's opts_m handling, checking .config (kernel defconfig) is problematic because savedefconfig elides options matching defconfig, making it impossible to distinguish overlay silence from defconfig agreement. The correct approach is to check only kernel_config_source_filename (the overlay) for explicit =y, otherwise default to =m, letting savedefconfig handle deduplication with defconfig automatically.
Applied to files:
config/kernel/linux-mvebu-current.configconfig/kernel/linux-mvebu64-current.config
📚 Learning: 2025-09-27T21:47:58.020Z
Learnt from: tabrisnet
Repo: armbian/build PR: 8678
File: config/kernel/linux-bcm2711-edge.config:859-861
Timestamp: 2025-09-27T21:47:58.020Z
Learning: In the Armbian build system, kernel configuration files in config/kernel/ are generated through an automated process: taking previous config → applying scripted changes from armbian-kernel.sh → running kernel's `make oldconfig` → processing by Armbian machinery back into config files. This automated process properly handles kernel configuration dependencies and reduces the likelihood of manual configuration errors.
Applied to files:
config/kernel/linux-mvebu-current.configconfig/kernel/linux-mvebu64-current.config
📚 Learning: 2025-11-02T20:49:56.719Z
Learnt from: igorpecovnik
Repo: armbian/build PR: 8849
File: config/boards/radxa-e54c.csc:14-28
Timestamp: 2025-11-02T20:49:56.719Z
Learning: In Armbian board configuration files (config/boards/*.conf, *.csc, etc.), do not use kernel_config_set, kernel_config_set_m, kernel_config_set_y, or custom_kernel_config__* functions to modify kernel configuration. Kernel configuration is associated with LINUXFAMILY/BOARDFAMILY, not individual BOARD. Board-specific kernel modifications cause inconsistency in kernel packages published to the apt repository because boards within a family share the same kernel packages. Kernel configuration changes must be made in the appropriate kernel config file (e.g., config/kernel/linux-*-*.config) or in family configuration files (config/sources/families/*.conf, *.inc) instead.
Applied to files:
config/kernel/linux-mvebu-current.configconfig/kernel/linux-mvebu64-current.config
📚 Learning: 2025-09-22T21:52:01.225Z
Learnt from: tabrisnet
Repo: armbian/build PR: 8661
File: lib/functions/compilation/armbian-kernel.sh:194-201
Timestamp: 2025-09-22T21:52:01.225Z
Learning: In lib/functions/compilation/armbian-kernel.sh, the kernel_config_modifying_hashes array is not universally required for all kernel configuration functions - some functions like armbian_kernel_config__netkit() operate without it, and adding entries with '=m' would be incorrect when the actual result might be '=y' for options already built-in.
Applied to files:
config/kernel/linux-mvebu-current.configconfig/kernel/linux-mvebu64-current.config
📚 Learning: 2025-08-02T05:46:10.664Z
Learnt from: EvilOlaf
Repo: armbian/build PR: 0
File: :0-0
Timestamp: 2025-08-02T05:46:10.664Z
Learning: In the Armbian build system, the KERNEL_CONFIGURE=yes switch is deprecated. The recommended approach for kernel configuration is now to use the `kernel-config` build command, which provides a more structured way to configure kernel options.
Applied to files:
config/kernel/linux-mvebu-current.config
📚 Learning: 2025-09-27T21:49:27.188Z
Learnt from: tabrisnet
Repo: armbian/build PR: 8678
File: config/kernel/linux-k3-edge.config:97-99
Timestamp: 2025-09-27T21:49:27.188Z
Learning: make oldconfig preserves existing deprecated kernel options and only prompts for new configuration options, unlike make defconfig which would auto-correct by removing deprecated options. This explains why deprecated options like CONFIG_ZSWAP_ZPOOL_DEFAULT_ZBUD might persist through the automated Armbian kernel configuration generation process.
Applied to files:
config/kernel/linux-mvebu-current.config
📚 Learning: 2025-09-27T21:49:55.796Z
Learnt from: tabrisnet
Repo: armbian/build PR: 8678
File: config/kernel/linux-sm8250-current.config:78-80
Timestamp: 2025-09-27T21:49:55.796Z
Learning: In the Armbian build system, kernel configuration files are generated through an automated process: taking previous config → applying scripted changes from armbian-kernel.sh → running kernel's `make oldconfig` → processing by Armbian machinery back into config files. This automated process properly handles kernel configuration dependencies and reduces the likelihood of manual configuration errors.
Applied to files:
config/kernel/linux-mvebu-current.configconfig/kernel/linux-mvebu64-current.config
📚 Learning: 2025-10-22T07:56:19.424Z
Learnt from: igorpecovnik
Repo: armbian/build PR: 8789
File: config/kernel/linux-sunxi64-edge.config:839-839
Timestamp: 2025-10-22T07:56:19.424Z
Learning: In Linux kernel configuration, some `=y` (builtin) options are infrastructure or feature flags that enable subsystems or features for modular drivers, rather than directly compiling code into the kernel. For example, in Armbian wireless configs, options like CONFIG_SPARD_WLAN_SUPPORT=y, CONFIG_SC23XX=y, CONFIG_WCN_BSP_DRIVER_BUILDIN=y, CONFIG_UNISOC_WIFI_PS=y are module infrastructure/feature enablers, while the actual drivers (CONFIG_WLAN_UWE5621=m, CONFIG_WLAN_UWE5622=m) remain as loadable modules. These infrastructure options don't cause kernel bloat.
Applied to files:
config/kernel/linux-mvebu-current.configconfig/kernel/linux-mvebu64-current.config
📚 Learning: 2025-07-27T15:56:34.414Z
Learnt from: pyavitz
Repo: armbian/build PR: 8421
File: config/kernel/linux-sunxi64-edge.config:438-439
Timestamp: 2025-07-27T15:56:34.414Z
Learning: CONFIG_NET_SCH_DEFAULT is a boolean kernel configuration option (=y or =n) that enables/disables the ability to override the default network queueing discipline at runtime. When set to 'y', it allows setting the actual qdisc name via /proc/sys/net/core/default_qdisc at runtime, not in the kernel config file itself.
Applied to files:
config/kernel/linux-mvebu-current.configconfig/kernel/linux-mvebu64-current.config
📚 Learning: 2025-09-27T21:50:04.845Z
Learnt from: tabrisnet
Repo: armbian/build PR: 8678
File: config/kernel/linux-sm8250-edge.config:80-82
Timestamp: 2025-09-27T21:50:04.845Z
Learning: In the Armbian build system, kernel configuration files are generated through this automated process: taking previous config → applying scripted changes from armbian-kernel.sh → running kernel's `make oldconfig` → processing by Armbian machinery back into config files. This automated process properly handles kernel configuration dependencies and reduces the likelihood of manual configuration errors.
Applied to files:
config/kernel/linux-mvebu64-current.config
📚 Learning: 2025-09-22T21:52:01.225Z
Learnt from: tabrisnet
Repo: armbian/build PR: 8661
File: lib/functions/compilation/armbian-kernel.sh:194-201
Timestamp: 2025-09-22T21:52:01.225Z
Learning: The kernel_config_set_m function in lib/functions/compilation/armbian-kernel.sh preserves existing 'y' (built-in) settings and only sets options to 'm' (module) when they are not already built-in, achieving "prefer modules but allow built-ins" behavior.
Applied to files:
config/kernel/linux-mvebu64-current.config
📚 Learning: 2025-07-15T21:09:23.252Z
Learnt from: pyavitz
Repo: armbian/build PR: 8383
File: config/kernel/linux-sunxi64-edge.config:57-64
Timestamp: 2025-07-15T21:09:23.252Z
Learning: In Linux kernel configuration, when CONFIG_CPU_FREQ_DEFAULT_GOV_ONDEMAND=y is set, the ondemand governor is implicitly enabled by default, making the explicit CONFIG_CPU_FREQ_GOV_ONDEMAND=y line redundant. The make menuconfig tool automatically removes such redundant lines. This behavior applies to CPU frequency governor configurations in general - setting a default governor automatically enables that governor.
Applied to files:
config/kernel/linux-mvebu64-current.config
🔇 Additional comments (3)
config/kernel/linux-mvebu-current.config (1)
7-8: LGTM! Tickless idle configuration is correct.The addition of
CONFIG_NO_HZ_COMMON=yandCONFIG_NO_HZ_IDLE=yproperly enables tickless idle mode for energy savings. These options are correctly configured with NO_HZ_COMMON as the required dependency for NO_HZ_IDLE.config/kernel/linux-mvebu64-current.config (2)
8-9: LGTM! Tickless idle configuration is correct.The addition of
CONFIG_NO_HZ_COMMON=yandCONFIG_NO_HZ_IDLE=yproperly enables tickless idle mode for energy savings on the 64-bit mvebu platform.
64-64: LGTM! MENU governor is appropriate for tickless idle.The change to
CONFIG_CPU_IDLE_GOV_MENU=yis correct for tickless idle systems. The MENU governor uses more sophisticated algorithms to predict idle duration compared to LADDER, making it better suited for NO_HZ_IDLE configurations.
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Switch to NO_HZ_IDLE for energy saving. Also enable Menu cpuidle governor for tickless systems.
Inspired by openwrt/openwrt#21136
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