leandrof/linux
1
0
Fork 0
Code Issues Pull Requests Packages Projects Releases Wiki Activity
mainlining shenanigans
770,745 Commits 2 Branches 0 Tags 5.1 GiB
C 97.7%
Assembly 1.1%
Shell 0.4%
Makefile 0.3%
Python 0.2%
Other 0.1%
5ef499cd57
Go to file
Rafael J. Wysocki 5ef499cd57 cpuidle: menu: Handle stopped tick more aggressively 
Commit 87c9fe6ee4 (cpuidle: menu: Avoid selecting shallow states
with stopped tick) missed the case when the target residencies of
deep idle states of CPUs are above the tick boundary which may cause
the CPU to get stuck in a shallow idle state for a long time.

Say there are two CPU idle states available: one shallow, with the
target residency much below the tick boundary and one deep, with
the target residency significantly above the tick boundary.  In
that case, if the tick has been stopped already and the expected
next timer event is relatively far in the future, the governor will
assume the idle duration to be equal to TICK_USEC and it will select
the idle state for the CPU accordingly.  However, that will cause the
shallow state to be selected even though it would have been more
energy-efficient to select the deep one.

To address this issue, modify the governor to always use the time
till the closest timer event instead of the predicted idle duration
if the latter is less than the tick period length and the tick has
been stopped already.  Also make it extend the search for a matching
idle state if the tick is stopped to avoid settling on a shallow
state if deep states with target residencies above the tick period
length are available.

In addition, make it always indicate that the tick should be stopped
if it has been stopped already for consistency.

Fixes: 87c9fe6ee4 (cpuidle: menu: Avoid selecting shallow states with stopped tick)
Reported-by: Leo Yan <leo.yan@linaro.org>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: 4.17+ <stable@vger.kernel.org> # 4.17+
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2018-08-20 13:37:03 +02:00
arch x86/ACPI/cstate: Make APCI C1 FFH MWAIT C-state description vendor-neutral 2018-08-15 00:19:38 +02:00
block for-4.19/block-20180812 2018-08-14 10:23:25 -07:00
certs certs/blacklist: fix const confusion 2018-06-26 09:43:03 -07:00
crypto Merge branch 'linus' of git://git.kernel.org/pub/scm/linux/kernel/git/herbert/crypto-2.6 2018-07-19 07:32:44 -07:00
Documentation Power management updates for 4.19-rc1 2018-08-14 13:12:24 -07:00
drivers cpuidle: menu: Handle stopped tick more aggressively 2018-08-20 13:37:03 +02:00
firmware kbuild: remove all dummy assignments to obj- 2017-11-18 11:46:06 +09:00
fs configfs updates for 4.19 2018-08-14 11:44:18 -07:00
include Power management updates for 4.19-rc1 2018-08-14 13:12:24 -07:00
init Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux 2018-08-13 19:07:17 -07:00
ipc Merge branch 'work.open3' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2018-08-13 19:58:36 -07:00
kernel sched: idle: Avoid retaining the tick when it has been stopped 2018-08-20 11:25:55 +02:00
lib JFFS2 changes: 2018-08-14 10:57:44 -07:00
LICENSES LICENSES: Add Linux-OpenIB license text 2018-04-27 16:41:53 -06:00
mm Power management updates for 4.19-rc1 2018-08-14 13:12:24 -07:00
net LED updates for 4.19-rc1 2018-08-14 13:07:22 -07:00
samples samples/bpf: xdp_redirect_cpu adjustment to reproduce teardown race easier 2018-08-09 21:50:44 +02:00
scripts lib/ubsan: remove null-pointer checks 2018-08-10 20:19:58 -07:00
security Merge branch 'work.open3' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2018-08-13 19:58:36 -07:00
sound ALSA: hda/realtek - Yet another Clevo P950 quirk entry 2018-07-18 12:17:46 +02:00
tools Merge branch 'l1tf-final' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2018-08-14 09:46:06 -07:00
usr kbuild: rename built-in.o to built-in.a 2018-03-26 02:01:19 +09:00
virt Merge branch 'sched/urgent' into sched/core, to pick up fixes 2018-07-25 11:29:58 +02:00
.clang-format clang-format: add configuration file 2018-04-11 10:28:35 -07:00
.cocciconfig
.get_maintainer.ignore
.gitattributes .gitattributes: set git diff driver for C source code files 2016-10-07 18:46:30 -07:00
.gitignore Kbuild updates for v4.17 (2nd) 2018-04-15 17:21:30 -07:00
.mailmap mailmap: remap some of my email addresses to kernel.org address 2018-08-06 13:15:16 -04:00
COPYING COPYING: use the new text with points to the license files 2018-03-23 12:41:45 -06:00
CREDITS MAINTAINERS/CREDITS: Drop METAG ARCHITECTURE 2018-03-05 16:34:24 +00:00
Kbuild Kbuild updates for v4.15 2017-11-17 17:45:29 -08:00
Kconfig kconfig: add basic helper macros to scripts/Kconfig.include 2018-05-29 03:31:19 +09:00
MAINTAINERS This is the bulk of pin control changes for v4.19: 2018-08-14 12:31:27 -07:00
Makefile Linux 4.18 2018-08-12 13:41:04 -07:00
README Docs: Added a pointer to the formatted docs to README 2018-03-21 09:02:53 -06:00

README 

Linux kernel
============

There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.

In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``.  The formatted documentation can also be read online at:

    https://www.kernel.org/doc/html/latest/

There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
See Documentation/00-INDEX for a list of what is contained in each file.

Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.