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https://lkml.org/lkml/2016/9/14/208 Interactive governor has lived in Android sources for a very long time and this commit is based on the code present in following branch: https://android.googlesource.com/kernel/common android-4.4 The Interactive governor is designed for latency-sensitive workloads, such as interactive user interfaces like the mobile phones and tablets. The interactive governor aims to be significantly more responsive to ramp CPU quickly up when CPU-intensive activity begins. Existing governors sample CPU load at a particular rate, typically every X ms and then update the frequency from a work-handler. This can lead to under-powering UI threads for the period of time during which the user begins interacting with a previously-idle system until the next sample period happens. The 'interactive' governor uses a different approach. A real-time thread is used for scaling up, giving the remaining tasks the CPU performance benefit, unlike existing governors which are more likely to schedule ramp-up work to occur after your performance starved tasks have completed. The Android version of interactive governor also checks whether to scale the CPU frequency up soon after coming out of idle. When the CPU comes out of idle, the governor check if the CPU sampling is overdue or not. If yes, it immediately starts the sampling. Otherwise, the utilization hooks from the scheduler handle the sampling later. If the CPU is very busy from exiting idle to when the evaluation happens, then it assumes that the CPU is under-powered and ramps it to MAX speed. If the CPU was not sufficiently busy to immediately ramp to MAX speed, then the governor evaluates the CPU load since the last speed adjustment, choosing the highest value between that longer-term load or the short-term load since idle exit to determine the CPU speed to ramp to. The core of this code is written and maintained (in Android repositories) by Mike Chan and Todd Poyner over a long period of time. Vireshk has made changes to to the governor to align it with the current practices followed with mainline governors, like using utilization hooks from the scheduler and handling kobject (for governor's sysfs directory) in a race free manner. And of course this included general cleanup of the governor as well. Signed-off-by: Mike Chan <mike@android.com> Signed-off-by: Todd Poynor <toddpoynor@google.com> Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org> Change-Id: Ib5e8d1dab0fa3cc5ba79b7a554c8dde35435cbdb [AmitP: Cherry-picked this version from https://git.kernel.org/cgit/linux/kernel/git/vireshk/pm.git/log/?h=cpufreq/interactive-idle-notifier. Also refactored and folded https://lkml.org/lkml/2016/9/14/209 patch into this unified patch.] Signed-off-by: Amit Pundir <amit.pundir@linaro.org> Signed-off-by: Liang Chen <cl@rock-chips.com> (cherry picked from https://android.googlesource.com/kernel/msm commit 33f7a05d4e82c81841af20e6a944a4c3f9b2973e)
How do I submit patches to Android Common Kernels
-
BEST: Make all of your changes to upstream Linux. If appropriate, backport to the stable releases. These patches will be merged automatically in the corresponding common kernels. If the patch is already in upstream Linux, post a backport of the patch that conforms to the patch requirements below.
- Do not send patches upstream that contain only symbol exports. To be considered for upstream Linux,
additions of
EXPORT_SYMBOL_GPL()require an in-tree modular driver that uses the symbol -- so include the new driver or changes to an existing driver in the same patchset as the export. - When sending patches upstream, the commit message must contain a clear case for why the patch is needed and beneficial to the community. Enabling out-of-tree drivers or functionality is not not a persuasive case.
- Do not send patches upstream that contain only symbol exports. To be considered for upstream Linux,
additions of
-
LESS GOOD: Develop your patches out-of-tree (from an upstream Linux point-of-view). Unless these are fixing an Android-specific bug, these are very unlikely to be accepted unless they have been coordinated with kernel-team@android.com. If you want to proceed, post a patch that conforms to the patch requirements below.
Common Kernel patch requirements
- All patches must conform to the Linux kernel coding standards and pass
script/checkpatch.pl - Patches shall not break gki_defconfig or allmodconfig builds for arm, arm64, x86, x86_64 architectures (see https://source.android.com/setup/build/building-kernels)
- If the patch is not merged from an upstream branch, the subject must be tagged with the type of patch:
UPSTREAM:,BACKPORT:,FROMGIT:,FROMLIST:, orANDROID:. - All patches must have a
Change-Id:tag (see https://gerrit-review.googlesource.com/Documentation/user-changeid.html) - If an Android bug has been assigned, there must be a
Bug:tag. - All patches must have a
Signed-off-by:tag by the author and the submitter
Additional requirements are listed below based on patch type
Requirements for backports from mainline Linux: UPSTREAM:, BACKPORT:
- If the patch is a cherry-pick from Linux mainline with no changes at all
- tag the patch subject with
UPSTREAM:. - add upstream commit information with a
(cherry picked from commit ...)line - Example:
- if the upstream commit message is
- tag the patch subject with
important patch from upstream
This is the detailed description of the important patch
Signed-off-by: Fred Jones <fred.jones@foo.org>
- then Joe Smith would upload the patch for the common kernel as
UPSTREAM: important patch from upstream
This is the detailed description of the important patch
Signed-off-by: Fred Jones <fred.jones@foo.org>
Bug: 135791357
Change-Id: I4caaaa566ea080fa148c5e768bb1a0b6f7201c01
(cherry picked from commit c31e73121f4c1ec41143423ac6ce3ce6dafdcec1)
Signed-off-by: Joe Smith <joe.smith@foo.org>
- If the patch requires any changes from the upstream version, tag the patch with
BACKPORT:instead ofUPSTREAM:.- use the same tags as
UPSTREAM: - add comments about the changes under the
(cherry picked from commit ...)line - Example:
- use the same tags as
BACKPORT: important patch from upstream
This is the detailed description of the important patch
Signed-off-by: Fred Jones <fred.jones@foo.org>
Bug: 135791357
Change-Id: I4caaaa566ea080fa148c5e768bb1a0b6f7201c01
(cherry picked from commit c31e73121f4c1ec41143423ac6ce3ce6dafdcec1)
[joe: Resolved minor conflict in drivers/foo/bar.c ]
Signed-off-by: Joe Smith <joe.smith@foo.org>
Requirements for other backports: FROMGIT:, FROMLIST:,
- If the patch has been merged into an upstream maintainer tree, but has not yet
been merged into Linux mainline
- tag the patch subject with
FROMGIT: - add info on where the patch came from as
(cherry picked from commit <sha1> <repo> <branch>). This must be a stable maintainer branch (not rebased, so don't uselinux-nextfor example). - if changes were required, use
BACKPORT: FROMGIT: - Example:
- if the commit message in the maintainer tree is
- tag the patch subject with
important patch from upstream
This is the detailed description of the important patch
Signed-off-by: Fred Jones <fred.jones@foo.org>
- then Joe Smith would upload the patch for the common kernel as
FROMGIT: important patch from upstream
This is the detailed description of the important patch
Signed-off-by: Fred Jones <fred.jones@foo.org>
Bug: 135791357
(cherry picked from commit 878a2fd9de10b03d11d2f622250285c7e63deace
https://git.kernel.org/pub/scm/linux/kernel/git/foo/bar.git test-branch)
Change-Id: I4caaaa566ea080fa148c5e768bb1a0b6f7201c01
Signed-off-by: Joe Smith <joe.smith@foo.org>
- If the patch has been submitted to LKML, but not accepted into any maintainer tree
- tag the patch subject with
FROMLIST: - add a
Link:tag with a link to the submittal on lore.kernel.org - add a
Bug:tag with the Android bug (required for patches not accepted into a maintainer tree) - if changes were required, use
BACKPORT: FROMLIST: - Example:
- tag the patch subject with
FROMLIST: important patch from upstream
This is the detailed description of the important patch
Signed-off-by: Fred Jones <fred.jones@foo.org>
Bug: 135791357
Link: https://lore.kernel.org/lkml/20190619171517.GA17557@someone.com/
Change-Id: I4caaaa566ea080fa148c5e768bb1a0b6f7201c01
Signed-off-by: Joe Smith <joe.smith@foo.org>
Requirements for Android-specific patches: ANDROID:
- If the patch is fixing a bug to Android-specific code
- tag the patch subject with
ANDROID: - add a
Fixes:tag that cites the patch with the bug - Example:
- tag the patch subject with
ANDROID: fix android-specific bug in foobar.c
This is the detailed description of the important fix
Fixes: 1234abcd2468 ("foobar: add cool feature")
Change-Id: I4caaaa566ea080fa148c5e768bb1a0b6f7201c01
Signed-off-by: Joe Smith <joe.smith@foo.org>
- If the patch is a new feature
- tag the patch subject with
ANDROID: - add a
Bug:tag with the Android bug (required for android-specific features)
- tag the patch subject with