path: root/members/arm/android/images/vexpress-lsk/HOWTO_releasenotes.txt

h1. Linaro Stable Kernel (LSK) 15.04 Release for Versatile Express (Android)

p. The Linaro Stable Kernel (LSK) is produced, validated and released by Linaro and is based on the linux stable kernel tree. It is produced to satisfy the requirements of Linaro members. The LSK focuses on quality and stability and is therefore a great basis for member products. It also includes backports of commonly desired features, provided they meet the quality requirements, and also any bug fixes.

p. Linaro releases monthly binary images for the ARM "Versatile Express":http://www.arm.com/products/tools/development-boards/versatile-express/index.php including support for Cortex-A9, Cortex-A5, TC2 (big.LITTLE) CoreTiles and Fast Models.

p. For support matters related to ARM hardware or firmware images downloaded from ARM sites, please contact "ARM support":mailto:support@arm.com

p. This release includes Linaro Android Jelly Bean for both Versatile Express and Fast Models. The images are able to boot A5, A9 and TC2 using UEFI. Sources are also made available so you can build your own images (see the "'Building from Source'":https://releases.linaro.org/15.04/members/arm/android/vexpress-lsk/#tabs-3 tab).

h2. About the TC2 Engineering Build

This release is based on the Linux v3.10.65 kernel.  As a consequence, almost all of the patches in the ARM Landing Team tree have been rebased and refactored to account for the latest upstream content.

The TC2 CoreTile is the first example of a big.LITTLE system shipped by ARM and serves as a platform for development and test of big.LITTLE software. TC2 contains a tri-core Cortex-A7 cluster and a dual-core Cortex-A15 cluster linked using the CCI-400 coherent interconnect.

The release contains the big.LITTLE MP patchset developed by ARM. This patchset is hosted by Linaro and can be found in the linked "git repository":https://git.linaro.org/gitweb?p=arm/big.LITTLE/mp.git;a=shortlog;h=refs/heads/big-LITTLE-MP-latest.  These patches have been developed and rigorously tested in order to enable the ARM Versatile Express V2P-CA15_A7 CoreTile (TC2) to run in full MP mode. This functionality has been optimised for energy and performance bringing it close to the Cortex-A7 (LITTLE) in energy consumption with near Cortex-A15 (big) performance. The patchset also includes optimizations that provide a considerable performance uplift across a wide range of benchmarks. The functionality introduced by this patchset is stable and ready for use on other platforms. Note that at present this LSK release is the reference point for big.LITTLE MP functionality.

The patches in the big.LITTLE MP patchset are generic and applicable to big.LITTLE systems with minimal porting effort. To ease porting, the patches are also available as an isolated package located "here":https://wiki.linaro.org/ARM/VersatileExpress?action=AttachFile&do=get&target=big-LITTLE-MP-scheduler-patchset-15.04-lsk.tar.bz2.  This package may be used directly by partners interested in porting the big.LITTLE MP scheduler functionality to their custom platform. Please contact "ARM support":mailto:support-sw@arm.com?subject=Query%20about%20ARM%20big.LITTLE%20MP%20patchset%20package in case of any queries related to this package.

Also provided is optional configurable kernel support for an implementation of ARM's Power State Co-ordination Interface (PSCI). This support is disabled by default. To use PSCI support you will require secure firmware that is currently available to ARM licensees upon request to ARM. Please contact "ARM support":mailto:support-sw@arm.com?subject=Access%20to%20PSCI to get access to the firmware code.

The 'small task packing feature' continues to be enabled by default in the kernel configuration. (See the documentation for this feature located at 'Documentation/arm/small_task_packing.txt’ within the kernel sources for more information on this feature).

Please note that this release does not introduce any new functionality.  However the release does contain one bug fix – see the patch marked 'New in this release’ in the list below for details.

h3. Scheduler modifications to support big.LITTLE

The following patches make up the big.LITTLE MP patchset. 

| "sched: implement usage tracking":https://git.linaro.org/gitweb?p=kernel/linux-linaro-stable.git;a=commit;h=0841c6ae0b53d43e4634cf4a1f88407b93c15399 | |
| "sched: entity load-tracking load_avg_ratio":https://git.linaro.org/gitweb?p=kernel/linux-linaro-stable.git;a=commit;h=be6ef1d56e70bfdfd79174d7d23a4b12d5b911ee | |
| "sched: Task placement for heterogeneous systems based on task load-tracking":https://git.linaro.org/gitweb?p=kernel/linux-linaro-stable.git;a=commit;h=798e82cab1a39f4d75796be024c4d7b08bc062e8 | |
| "sched: Forced task migration on heterogeneous systems":https://git.linaro.org/gitweb?p=kernel/linux-linaro-stable.git;a=commit;h=2dd22b22c95851445c189c3d4708c027aa19cf5f | |
| "sched: Introduce priority-based task migration filter":https://git.linaro.org/gitweb?p=kernel/linux-linaro-stable.git;a=commit;h=943106d9437fcced79c4e48ed794410e5f750b4c | |
| "ARM: Add HMP scheduling support for ARM architecture":https://git.linaro.org/gitweb?p=kernel/linux-linaro-stable.git;a=commit;h=d278bb1c4d5191e0d9b9911337e3b31a100a7f9f | |
| "ARM: sched: Use device-tree to provide fast/slow CPU list for HMP":https://git.linaro.org/gitweb?p=kernel/linux-linaro-stable.git;a=commit;h=dc68bd92107d8990f4608d8f42744770fe203f7f | |
| "ARM: sched: Setup SCHED_HMP domains":https://git.linaro.org/gitweb?p=kernel/linux-linaro-stable.git;a=commit;h=1baaccf456ece33b8fa02f8cdf3977d6a95b393c | |
| "sched: Add ftrace events for entity load-tracking":https://git.linaro.org/gitweb?p=kernel/linux-linaro-stable.git;a=commit;h=b9d3d5612899de4f8372ecfbc4c8f4ba5aa170ec | |
| "sched: Add HMP task migration ftrace event":https://git.linaro.org/gitweb?p=kernel/linux-linaro-stable.git;a=commit;h=0d811e649ad31994e8f06b6b18101f249b34e912 | |
| "sched: SCHED_HMP multi-domain task migration control":https://git.linaro.org/gitweb?p=kernel/linux-linaro-stable.git;a=commit;h=76525733b4f4e0fdcc188dfe23941024ae626979 | |
| "sched: Enable HMP priority filter by default":https://git.linaro.org/gitweb?p=kernel/linux-linaro-stable.git;a=commit;h=1b8ae251638844173bd04a4c9e543581f3d92fbd | |
| "ARM: sched: Avoid empty 'slow' HMP domain":https://git.linaro.org/gitweb?p=kernel/linux-linaro-stable.git;a=commit;h=362036513b1dff299b2035d5b928a203742b98d7 | |
| "sched: Only down migrate low priority tasks if allowed by affinity mask":https://git.linaro.org/gitweb?p=kernel/linux-linaro-stable.git;a=commit;h=eeebbf595c8dcd6392537c4d13b8cda78001f4e5 | |
| "sched: fix arch_get_fast_and_slow_cpus to get logical cpumask correctly":https://git.linaro.org/gitweb?p=kernel/linux-linaro-stable.git;a=commit;h=a9f9bca843e44144670c660638274363f34b9847 | |
| "sched: Do not ignore grouped tasks during HMP forced migration.":https://git.linaro.org/gitweb?p=kernel/linux-linaro-stable.git;a=commit;h=d2c920023cbc456414f8e07ff253a89be535b41b | |
| "sched: Ignore offline CPUs in HMP migration & load stats":https://git.linaro.org/gitweb?p=kernel/linux-linaro-stable.git;a=commit;h=b64cc6f7e54b97536dbecc05d193b31b27feecf1 | |
| "ARM: Change load tracking scale using sysfs":https://git.linaro.org/gitweb?p=kernel/linux-linaro-stable.git;a=commit;h=0e48eed05c47aa2e00b772a519b36286e466621e | |
| "ARM: Experimental Frequency-Invariant Load Scaling Patch":https://git.linaro.org/gitweb?p=kernel/linux-linaro-stable.git;a=commit;h=71b5dbd6d527d5de8aaef7e1f8658df95caf28aa | |
| "ARM: Fix build breakage when big.LITTLE.conf is not used.":https://git.linaro.org/gitweb?p=kernel/linux-linaro-stable.git;a=commit;h=ae570aeb1d40d531a498e53e2a815a52996f0749 | |
| "sched: Basic global balancing support for HMP":https://git.linaro.org/gitweb?p=kernel/linux-linaro-stable.git;a=commit;h=cf71912f481c7b6fc39e9b2021e8f9c058116c26 | |
| "sched: cfs.nr_running does not contain the intended metric":https://git.linaro.org/gitweb?p=kernel/linux-linaro-stable.git;a=commit;h=7e6446630039fcbabb9582ebefdcbc30de32c0e2 | |
| "Revert sched: Enable HMP priority filter by default":https://git.linaro.org/gitweb?p=kernel/linux-linaro-stable.git;a=commit;h=7362251d8a422dcba5c56408b92fc2b6ad03b10c | |
| "HMP: Use unweighted load for hmp migration decisions":https://git.linaro.org/gitweb?p=kernel/linux-linaro-stable.git;a=commit;h=ede58a69a32b187899e6cccbbd299a04d3f50b71 | |
| "HMP: Select least-loaded CPU when performing HMP Migrations":https://git.linaro.org/gitweb?p=kernel/linux-linaro-stable.git;a=commit;h=08d7db89a214a138516419a85e17272b09180abd | |
| "HMP: Avoid multiple calls to hmp_domain_min_load in fast path":https://git.linaro.org/gitweb?p=kernel/linux-linaro-stable.git;a=commit;h=3f3b210703f80fe60dbfa13c25b30d4effbf9f4b | |
| "HMP: Force new non-kernel tasks onto big CPUs until load stabilises":https://git.linaro.org/gitweb?p=kernel/linux-linaro-stable.git;a=commit;h=954978dd2cff81cc15745b9e581a1709e238f8ef | |
| "sched: Restrict nohz balance kicks to stay in the HMP domain":https://git.linaro.org/gitweb?p=kernel/linux-linaro-stable.git;a=commit;h=6eada0087366d8aec6bc38348a68f721f538cc5c | |
| "HMP: experimental: Force all rt tasks to start on little domain":https://git.linaro.org/gitweb?p=kernel/linux-linaro-stable.git;a=commit;h=4ab2679351e9566a6b0822f2d841a902758ba066 | |
| "HMP: Check the system has little cpus before forcing rt tasks to them":https://git.linaro.org/?p=kernel/linux-linaro-stable.git;a=commit;h=0d5ddd14a8e67d35fad79caf479cca54a6788cc9 | |
| "HMP: select 'best' task for migration rather than 'current'":https://git.linaro.org/gitweb?p=kernel/linux-linaro-stable.git;a=commit;h=ee52487aaf659ef630ce3371de0e59944253581b | |
| "sched: HMP fix traversing the rb-tree from the curr pointer":https://git.linaro.org/gitweb?p=kernel/linux-linaro-stable.git;a=commit;h=aaba2453951b3743d003be228102e1da63c75326 | |
| "sched: track per-rq 'last migration time'":https://git.linaro.org/gitweb?p=kernel/linux-linaro-stable.git;a=commit;h=5fad81c7739db3a1fc6380dcc3d7902666ed5ee8 | |
| "HMP: Modify the runqueue stats to add a new child stat":https://git.linaro.org/gitweb?p=kernel/linux-linaro-stable.git;a=commit;h=b98cd6acc86f2c3bc10902476836746727b73ba9 | |
| "HMP: Explicitly implement all-load-is-max-load policy for HMP targets":https://git.linaro.org/gitweb?p=kernel/linux-linaro-stable.git;a=commit;h=6b695bd8a4e2c86cc466010517c0260dc3653742 | |
| "sched: HMP change nr_running offload metric":https://git.linaro.org/gitweb?p=kernel/linux-linaro-stable.git;a=commit;h=1f435579ea80d4639061435d8337df5a2c92e530 | |
| "HMP: Implement idle pull for HMP":https://git.linaro.org/gitweb?p=kernel/linux-linaro-stable.git;a=commit;h=db20b7088c6d7f7920dace95c7fc8d9955650214 | |
| "HMP: Access runqueue task clocks directly.":https://git.linaro.org/gitweb?p=kernel/linux-linaro-stable.git;a=commit;h=de66e01565848d0236ca9e7e9e2f6ecd5c27a021 | |
| "HMP: Update migration timer when we fork-migrate":https://git.linaro.org/gitweb?p=kernel/linux-linaro-stable.git;a=commit;h=18e3c3d2cc1346cb7cc2e3fd777b2c6f4fbb6135 | |
| "sched: HMP: Change default HMP thresholds":http://git.linaro.org/gitweb?p=kernel/linux-linaro-stable.git;a=commit;h=d73babce9a77f8143136fe0d7b6c1ae44b5652dc | |
| "sched: HMP: Additional trace points for debugging HMP":http://git.linaro.org/gitweb?p=kernel/linux-linaro-stable.git;a=commit;h=7b8e0b3f2af55b1ffb5c10be1daa59d8dc21d140 | |
| "arm: ipi raise/start/end tracing":http://git.linaro.org/gitweb?p=kernel/linux-linaro-stable.git;a=commit;h=2353c1f8009c14e89b323b18ae246c485fc034e4 | |
| "smp: smp_cross_call function pointer tracing":http://git.linaro.org/gitweb?p=kernel/linux-linaro-stable.git;a=commit;h=5ecaba3d9f4ab514fe8d383534e24b306f116896 | |
| "sched: HMP: fix potential logical errors":http://git.linaro.org/gitweb?p=kernel/linux-linaro-stable.git;a=commit;h=2e14ecb254a3eaa2993b5dd04014f41e1d6188ce | |
| "hmp: Remove potential for task_struct access race":http://git.linaro.org/gitweb?p=kernel/linux-linaro-stable.git;a=commit;h=cd5c2cc93d3dc581a19c62442f40895500d2a34c | |
| "HMP: Implement task packing for small tasks in HMP":http://git.linaro.org/gitweb?p=kernel/linux-linaro-stable.git;a=commit;h=d8063e7015122eb3f6173acf496171def8941734 | |
| "smp: Don't use typedef to work around compiler issues with tracepoints":https://git.linaro.org/kernel/linux-linaro-stable.git?a=commit;h=b9e7900a8ad0dc9ffe416567841cb606f1689133 | |
| "arm64: Fix build due to HMP tracepoints":https://git.linaro.org/kernel/linux-linaro-stable.git?a=commit;h=bd40e205ea48665ed60499001f8edf802e2901e2 | |
| "HMP: Avoid using the cpu stopper to stop runnable tasks":https://git.linaro.org/gitweb?p=kernel/linux-linaro-stable.git;a=commit;h=2a68d1e9125582bedeac4ea34fb9901ab1f7de11 | |
| "sched: hmp: add read-only hmp domain sysfs file":https://git.linaro.org/gitweb?p=kernel/linux-linaro-stable.git;a=commit;h=0b877c2baac65994016c6812804d1b30e89c18ed | |
| "Documentation: HMP: Small Task Packing explanation":https://git.linaro.org/gitweb?p=kernel/linux-linaro-stable.git;a=commit;h=f5be72980bc321f3491377861835c343cc27af0d | |
| "sched: hmp: Fix build breakage when not using CONFIG_SCHED_HMP":https://git.linaro.org/gitweb?p=kernel/linux-linaro-stable.git;a=commit;h=7cf6a7300bb9a88f543061270419427395ab4d2f | |
| "sched/debug: Add load-tracking statistics to task":https://git.linaro.org/kernel/linux-linaro-stable.git?a=commit;h=42f95a9ca82e0931ba134c9ec180ab7ae8d90dcc | |
| "config: Add config fragments for big LITTLE MP":https://git.linaro.org/kernel/linux-linaro-stable.git?a=commit;h=edecdef95ad50910270915aa0cdcf2f624301cac | |
| "genirq: Add default affinity mask command line option":https://git.linaro.org/kernel/linux-linaro-stable.git?a=commit;h=6bfbe7d9f891dc145ed395cf2b8c23b2dd9c74e8 | |
| "sched: reset blocked load decay_count during synchronization":https://git.linaro.org/kernel/linux-linaro-stable.git/commit/f720a920e88f1ec79db8c9f0031f61c610e40b02 | |
| "sched: update runqueue clock before migrations away":https://git.linaro.org/kernel/linux-linaro-stable.git/commit/7896b1e659db571556436b99ebb2e475e54a24f5 | |
| "sched: hmp: Make idle balance behaviour normal when packing disabled":https://git.linaro.org/kernel/linux-linaro-stable.git/commit/257e5075a1433513bb354f202adcd2dea8a8dc08 | |
| "sched: hmp: Change TC2 packing config to disabled default if present":https://git.linaro.org/kernel/linux-linaro-stable.git/commit/ba8ed8301f5bca4a44c80e2173c66391b76898df | |
| "config: Make packing present on TC2":https://git.linaro.org/kernel/linux-linaro-stable.git/commit/5e0791511a938eaf28d9071b411ffa71a79ef8ed | |
| "sched: hmp: Fix potential task_struct memory leak":https://git.linaro.org/kernel/linux-linaro-stable.git/commit/b2fafaba35f490947b78e8d0d4f4264a137e64cd | |
| "HMP: Restrict irq_default_affinity to hmp_slow_cpu_mask":https://git.linaro.org/kernel/linux-linaro-stable.git/commit/1d462599bee9a2f5f3988aafa43feda602d5e188 | |
| "HMP: Fix rt task allowed cpu mask restriction code on 1x1 system":https://git.linaro.org/kernel/linux-linaro-stable.git/commit/b30814c74c184bbb231e24d6c857699af338468b | |
| "hmp: sched: Clean up hmp_up_threshold checks into a utility fn":https://git.linaro.org/kernel/linux-linaro-stable.git/commit/765aae2 | |
| "sched: hmp: unify active migration code":https://git.linaro.org/kernel/linux-linaro-stable.git/commit/0baa581 | |
| "hmp: Use idle pull to perform forced up-migrations":https://git.linaro.org/kernel/linux-linaro-stable.git/commit/aae7721 | |
| "hmp: dont attempt to pull tasks if affinity doesn't allow it":https://git.linaro.org/kernel/linux-linaro-stable.git/commit/5a570cf | |
| "Revert hmp: dont attempt to pull tasks if affinity doesn't allow it":https://git.linaro.org/kernel/linux-linaro-stable.git/commit/8503bfd | |
| "Revert hmp: Use idle pull to perform forced up-migrations":https://git.linaro.org/kernel/linux-linaro-stable.git/commit/7e1f7d3 | |
| "Revert sched: hmp: unify active migration code":https://git.linaro.org/kernel/linux-linaro-stable.git/commit/11971ff | |
| "Revert hmp: sched: Clean up hmp_up_threshold checks into a utility fn":https://git.linaro.org/kernel/linux-linaro-stable.git/commit/db3dba6 | |
| "sched: hmp: Change small task packing defaults for all platforms":https://git.linaro.org/kernel/linux-linaro-stable.git/commit/1ade57e | |
| "hmp: sched: Clean up hmp_up_threshold checks into a utility fn":https://git.linaro.org/kernel/linux-linaro-stable.git/commit/84efcd0 | |
| "sched: hmp: unify active migration code":https://git.linaro.org/kernel/linux-linaro-stable.git/commit/0168997 | |
| "hmp: Use idle pull to perform forced up-migrations":https://git.linaro.org/kernel/linux-linaro-stable.git/commit/940407d | |
| "hmp: dont attempt to pull tasks if affinity doesn't allow it":https://git.linaro.org/kernel/linux-linaro-stable.git/commit/d1df056 | |
| "sched: hmp: fix out-of-range CPU possible":https://git.linaro.org/kernel/linux-linaro-stable.git/commit/4378062f289e67259f017f6b176ee385dc974836 | |
| "HMP: use per cpu cpuidle driver to fix deadlock in hmp_idle_pull":https://git.linaro.org/kernel/linux-linaro-stable.git/commit/65abdc9b50378783981ed2f3453a0aae090404e4 | |
| "HMP: Do not fork-boost tasks coming from PIDs <= 2":https://git.linaro.org/kernel/linux-linaro-stable.git/commit/f83262408293795e5186e9d1bf66d525b24fdb12 | |
| "hmp: Restrict ILB events if no CPU has > 1 task":https://git.linaro.org/kernel/linux-linaro-stable.git/commit/e482d95c1d1888f34cc3f7e6778806cfda6174ff | |
| "sched: hmp: fix spinlock recursion in active migration":https://git.linaro.org/kernel/linux-linaro-stable.git?a=commit;h=c1f0c1f51bf7b9111de27c3cdbea9b647351bf7b | |

h3. Platform Support. 

In addition to the big.LITTLE MP work the TC2 platform support includes:
** TC2: reset CPUs spuriously woken up on cluster power up
** vexpress: add shim layer for psci backend on TC2
** vexpress: allow native pm ops backends to probe for psci suppport
** psci: add cmdline option to enable use of psci
** psci: add probe function to discover presence of a psci implementation
** psci: convert psci '-EALREADYON' error code to linux '-EAGAIN'
** vexpress: add psci support in TC2 device tree
** psci: add constants to specify affinity levels
** TC2: replace hard coded cluster and cpu values with constants
** TC2: use generic accessors to extract cpu and cluster ids
** CPUidle & CPUfreq support
** hwmon driver allowing, amongst other things, TC2's power, current and energy measurements to be read through standard sysfs interfaces
** Common clocks implementation
** Regulator driver
** Drivers for previously hard-coded configuration interfaces
** Support self-hosted debugging through idle
** In addition to the CPU PMUs the perf framework supports the CCI-400 PMUs
** A patch from Thomas Gliexner which supports a IRQ affinity mask being specified in the command line. This can be used to reduce unnecessary IRQ wakeups on Cortex-A15. For instructions see the irqaffinity entry in Documentation/kernel-parameters.txt
** arm-multi_pmu_v2 - enables the use of multiple PMU types or sources, for example profiling across both Cortex-A15 and Cortex-A7 clusters and getting results for CCI. 

h2. Where To Find More Information

More information on Linaro can be found on our "website.":http://www.linaro.org/

h2. Feedback and Support

Subscribe to the important Linaro mailing lists and join our IRC channels to stay on top of Linaro development.

** Linaro Android Development "mailing list":http://lists.linaro.org/mailman/listinfo/linaro-android
** Linaro Android IRC channel on irc.freenode.net at @#linaro-android@

* Landing Team bug reports should be filed in "Bugzilla":https://bugs.linaro.org/buglist.cgi?component=General&list_id=731&product=ARM%20LT&resolution=--- by clicking on the "New":https://bugs.linaro.org/enter_bug.cgi link on the top menu bar.
** You will need to login to your Linaro account.  If you do not have an account or are having problems, email its@linaro.org for help.
* More general bug reports should be filed in Bugzilla against the individual packages that are affected.
* Questions? "ask Linaro":http://ask.linaro.org/.
* Interested in commercial support? inquire at "Linaro support":mailto:support@linaro.org

h2. Resolved in this release

None.

h2. Known Issues

h3. General Issues

* "Bug 55":https://bugs.linaro.org/show_bug.cgi?id=55 Stats for cpuidle time are always zero
* "Bug 138":https://bugs.linaro.org/show_bug.cgi?id=138 14.05 LSK pre-release validation shows degradation in BBench scores
* "Bug 141":https://bugs.linaro.org/show_bug.cgi?id=141 perf shows zero for cycle and instruction counts on TC2
* "Bug 143":https://bugs.linaro.org/show_bug.cgi?id=143 Audio playback under Android JellyBean stops sporadically on TC2 with release 13.03

h3. Known Issues due to lack of video acceleration

* "Bug 142":https://bugs.linaro.org/show_bug.cgi?id=142 vexpress: Angrybirds display severely truncated
* "Bug 160":https://bugs.linaro.org/show_bug.cgi?id=160 vexpress: YouTube video playback fails

h3. Known Issues due to generic Android features

* "Bug 140":https://bugs.linaro.org/show_bug.cgi?id=140 Gallery app crashes on start on vexpress Android 4.3
* "Bug 139":https://bugs.linaro.org/show_bug.cgi?id=139 Panic in ip6tables during Android boot
* "Bug 197":https://bugs.linaro.org/show_bug.cgi?id=197 Latest Android rootfs (4.4.3) caused performance regression on LSK with big.LITTLE patch set
* "Bug 250":https://bugs.linaro.org/show_bug.cgi?id=250 Vellamo is crashing on 4.4.2 and 4.4.3 builds on TC2

h3. Additional information

NOTE: When using the interactive governor with Android, take care to use the following values for governor specific tunables. These values have been selected after careful analysis on this LSK version and result in optimal power-performance on TC2. In future LSK releases, additional system initialisation logic will use these values as defaults.

Interactive settings for the Cortex-A7 cluster:

'above_hispeed_delay': 20000
'go_hispeed_load': 85
'hispeed_freq': 800000
'min_sample_time': 80000
'timer_rate': 20000

Interactive settings for the Cortex-A15 cluster:

'above_hispeed_delay': 20000
'go_hispeed_load': 85
'hispeed_freq': 1000000
'min_sample_time': 80000
'timer_rate': 20000