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Steve Muckle 7a1d4bf0d0 ANDROID: cpufreq/schedutil: add up/down frequency transition rate limits
The rate-limit tunable in the schedutil governor applies to transitions
to both lower and higher frequencies. On several platforms it is not the
ideal tunable though, as it is difficult to get best power/performance
figures using the same limit in both directions.

It is common on mobile platforms with demanding user interfaces to want
to increase frequency rapidly for example but decrease slowly.

One of the example can be a case where we have short busy periods
followed by similar or longer idle periods. If we keep the rate-limit
high enough, we will not go to higher frequencies soon enough. On the
other hand, if we keep it too low, we will have too many frequency
transitions, as we will always reduce the frequency after the busy
period.

It would be very useful if we can set low rate-limit while increasing
the frequency (so that we can respond to the short busy periods quickly)
and high rate-limit while decreasing frequency (so that we don't reduce
the frequency immediately after the short busy period and that may avoid
frequency transitions before the next busy period).

Implement separate up/down transition rate limits. Note that the
governor avoids frequency recalculations for a period equal to minimum
of up and down rate-limit. A global mutex is also defined to protect
updates to min_rate_limit_us via two separate sysfs files.

Note that this wouldn't change behavior of the schedutil governor for
the platforms which wish to keep same values for both up and down rate
limits.

This is tested with the rt-app [1] on ARM Exynos, dual A15 processor
platform.

Testcase: Run a SCHED_OTHER thread on CPU0 which will emulate work-load
for X ms of busy period out of the total period of Y ms, i.e. Y - X ms
of idle period. The values of X/Y taken were: 20/40, 20/50, 20/70, i.e
idle periods of 20, 30 and 50 ms respectively. These were tested against
values of up/down rate limits as: 10/10 ms and 10/40 ms.

For every test we noticed a performance increase of 5-10% with the
schedutil governor, which was very much expected.

[Viresh]: Simplified user interface and introduced min_rate_limit_us +
	      mutex, rewrote commit log and included test results.

[1] https://github.com/scheduler-tools/rt-app/.

Change-Id: I18720a83855b196b8e21dcdc8deae79131635b84
Signed-off-by: Steve Muckle <smuckle.linux@gmail.com>
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
(applied from https://marc.info/?l=linux-kernel&m=147936011103832&w=2)
[trivial adaptations]
Signed-off-by: Juri Lelli <juri.lelli@arm.com>
[updated rate limiting & fixed conflicts]
Signed-off-by: Chris Redpath <chris.redpath@arm.com>
Git-commit: 50c26fdb74563ec0cb4a83373d42667f4e83a23e
Git-repo: https://android.googlesource.com/kernel/common/
[dickey@codeaurora.org: Trivial cherry-pick conflicts]
Signed-off-by: Stephen Dickey <dickey@codeaurora.org>
2020-09-15 19:29:30 -07:00
android aarch64: ABI: add kernel_restart to GKI KMI symbol list 2020-08-18 21:29:05 +03:00
arch arm64: defconfig: enable CONFIG_DEBUG_PREEMPT for debug config 2020-08-22 03:44:26 -07:00
block FROMGIT: scsi: block: pm: Simplify resume handling 2020-08-06 15:18:05 +00:00
certs
crypto
Documentation Merge android11-5.4.57 (3f413d0) into msm-5.4 2020-08-10 05:01:21 -07:00
drivers Merge "arm64: defconfig: Set panic timeout and panic oops config" 2020-08-21 18:26:14 -07:00
fs Merge android11-5.4.57 (3f413d0) into msm-5.4 2020-08-10 05:01:21 -07:00
include Merge "arm64: defconfig: Set panic timeout and panic oops config" 2020-08-21 18:26:14 -07:00
init Perf: core: create/delete shared kernel/user events 2020-08-11 13:49:18 +05:30
ipc
kernel ANDROID: cpufreq/schedutil: add up/down frequency transition rate limits 2020-09-15 19:29:30 -07:00
lib Merge android11-5.4.57 (3f413d0) into msm-5.4 2020-08-10 05:01:21 -07:00
LICENSES
mm mm: Allow pages that are swapped in to come from the movable zone 2020-08-19 10:36:06 -07:00
net Merge "net: qrtr: haven: Add fragmentation support" 2020-08-15 07:11:21 -07:00
samples
scripts Merge android11-5.4.56 (fcb0d3e) into msm-5.4 2020-08-06 17:12:45 -07:00
security
sound Merge "sound: usb: Add NULL check against udev with uaudio_dev_cleanup() API" 2020-08-16 18:45:37 -07:00
techpack
tools This is the 5.4.57 stable release 2020-08-07 10:07:58 +02:00
usr
virt KVM: arm64: Don't inherit exec permission across page-table levels 2020-08-05 09:59:51 +02:00
.clang-format
.cocciconfig
.get_maintainer.ignore
.gitattributes
.gitignore
.mailmap
Android.bp
build.config.aarch64
build.config.allmodconfig
build.config.allmodconfig.aarch64
build.config.allmodconfig.arm
build.config.allmodconfig.x86_64
build.config.arm
build.config.common build.config.common: Move to clang-11 2020-08-05 14:34:03 -07:00
build.config.db845c
build.config.gki
build.config.gki-debug.aarch64
build.config.gki-debug.x86_64
build.config.gki.aarch64
build.config.gki.x86_64
build.config.gki_kasan
build.config.gki_kasan.aarch64
build.config.gki_kasan.x86_64
build.config.hikey960
build.config.msm.common
build.config.msm.gki
build.config.msm.lahaina
build.config.x86_64
build.targets
COPYING
CREDITS
gen_headers_arm.bp
gen_headers_arm64.bp
Kbuild
Kconfig
kernel_headers.py
MAINTAINERS
Makefile Merge android11-5.4.57 (3f413d0) into msm-5.4 2020-08-10 05:01:21 -07:00
modules.list.msm.lahaina
README
README.md

How do I submit patches to Android Common Kernels

  1. 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.

  2. 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:, or ANDROID:.
  • 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 ...) line
    • Example:
      • if the upstream commit message is
        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 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 of UPSTREAM:.
    • use the same tags as UPSTREAM:
    • add comments about the changes under the (cherry-picked from ...) line
    • Example:
        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 c31e73121f4c1ec41143423ac6ce3ce6dafdcec1)
        [ 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 use linux-next for example).
    • if changes were required, use BACKPORT: FROMGIT:
    • Example:
      • if the commit message in the maintainer tree is
        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
    • if changes were required, use BACKPORT: FROMLIST:
    • Example:
        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:
        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)