|From:||Trinabh Gupta <email@example.com>|
|To:||firstname.lastname@example.org, email@example.com, firstname.lastname@example.org, email@example.com, firstname.lastname@example.org, email@example.com, firstname.lastname@example.org|
|Subject:||[RFC PATCH V4 0/4] cpuidle: global registration of idle states with per-cpu statistics|
|Date:||Thu, 28 Apr 2011 22:02:10 +0530|
|Cc:||email@example.com, firstname.lastname@example.org, email@example.com, firstname.lastname@example.org, email@example.com, firstname.lastname@example.org|
The following patch series implements global registration of cpuidle states, and also has the necessary data structure changes to accommodate the per-cpu writable members of the cpuidle_states structure. Previous version of the series (V3) is at https://lkml.org/lkml/2011/4/20/23 This series applies on 2.6.39-rc5 with Len Brown's pm_idle() cleanup version 3 (https://lkml.org/lkml/2011/4/2/8) plus the patch https://lkml.org/lkml/diff/2011/4/25/54/1 Changes from previous version (V3): 1. Compile tested for ARM using the following configs: da8xx_omapl_defconfig, kirkwood_defconfig, stamp9g20_defconfig, omap2plus_defconfig. Boot tested on Panda SoC (OMAP4430) but it doesn't really use cpuidle. 2. Boot tested on x86 nehalem with multiple C-states for both intel_idle and acpi_idle drivers. 3. Boot tested on T60p thinkpad that has T2600 cpu with multiple C-states. Additionally tested the case when C-state tables change on AC <-> Battery power switch. 4. De-duplicated code in [1/4] and moved common code related to update of cpuidle statistics to drivers/cpuidle/cpuidle.c 5. Handled the case when acpi_processor_cst_has_changed() is called on x86 on switching power from AC <-> Battery. The implementation is just a prototype. Please provide suggestions. Brief description of the patches: The core change in this series is to split the cpuidle_device structure into parts that can be global and parts that has to remain per-cpu. The per-cpu pieces are mostly generic statistics that can be independent of current running driver. As a result of these changes, there is single copy of cpuidle_states structure and single registration done by one cpu. The low level driver is free to set per-cpu driver data on each cpu if needed using the cpuidle_set_statedata() as the case today. Only in very rare cases asymmetric C-states exist which can be handled within the cpuidle driver. Most architectures do not have asymmetric C-states. First two patches in the series facilitate splitting of cpuidle_states and cpuidle_device structure and next two patches do the actual split, change the API's and make existing code follow the changed API. [1/4] - Move the idle residency accounting part from cpuidle.c to the respective low level drivers, so that the accounting can be accurately maintained if the driver decides to demote the chosen (suggested) by the governor. [2/4] - removes the cpuidle_device()->prepare API since is is not widely used and the only use case was to allow software demotion using CPUIDLE_FLAG_IGNORE flag. Both these functions can be absorbed within the cpuidle back-end driver ad hence deprecating the prepare routine and the CPUIDLE_FLAG_IGNORE flag. - Ref: https://lkml.org/lkml/2011/3/25/52 [3/4] - Splits the usage statistics (read/write) part out of cpuidle_state structure, so that the states can become read only and hence made global. [4/4] - most APIs will now need to pass pointer to both global cpuidle_driver and per-cpu cpuidle_device structure. Thanks, -Trinabh -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to email@example.com More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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