Commit Graph

33 Commits

Author SHA1 Message Date
Peter Zijlstra
8e7fbcbc22 sched: Remove stale power aware scheduling remnants and dysfunctional knobs
It's been broken forever (i.e. it's not scheduling in a power
aware fashion), as reported by Suresh and others sending
patches, and nobody cares enough to fix it properly ...
so remove it to make space free for something better.

There's various problems with the code as it stands today, first
and foremost the user interface which is bound to topology
levels and has multiple values per level. This results in a
state explosion which the administrator or distro needs to
master and almost nobody does.

Furthermore large configuration state spaces aren't good, it
means the thing doesn't just work right because it's either
under so many impossibe to meet constraints, or even if
there's an achievable state workloads have to be aware of
it precisely and can never meet it for dynamic workloads.

So pushing this kind of decision to user-space was a bad idea
even with a single knob - it's exponentially worse with knobs
on every node of the topology.

There is a proposal to replace the user interface with a single
3 state knob:

 sched_balance_policy := { performance, power, auto }

where 'auto' would be the preferred default which looks at things
like Battery/AC mode and possible cpufreq state or whatever the hw
exposes to show us power use expectations - but there's been no
progress on it in the past many months.

Aside from that, the actual implementation of the various knobs
is known to be broken. There have been sporadic attempts at
fixing things but these always stop short of reaching a mergable
state.

Therefore this wholesale removal with the hopes of spurring
people who care to come forward once again and work on a
coherent replacement.

Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Suresh Siddha <suresh.b.siddha@intel.com>
Cc: Arjan van de Ven <arjan@linux.intel.com>
Cc: Vincent Guittot <vincent.guittot@linaro.org>
Cc: Vaidyanathan Srinivasan <svaidy@linux.vnet.ibm.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Link: http://lkml.kernel.org/r/1326104915.2442.53.camel@twins
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2012-05-17 13:48:56 +02:00
Hiroshi Shimamoto
489a71b029 sched: Update documentation and comments
Change sched_*.c to sched/*.c in documentation and comments.

Signed-off-by: Hiroshi Shimamoto <h-shimamoto@ct.jp.nec.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/4F795CAC.9080206@ct.jp.nec.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2012-05-07 15:04:18 +02:00
Rakib Mullick
30fd049afc sched: Remove sched_switch
Currently we don't utilize the sched_switch field anymore.

But, simply removing sched_switch field from the middle of the
sched_stat output will break tools.

So, to stay compatible we hardcode it to zero and remove the
field from the scheduler data structures.

Update the schedstat documentation accordingly.

Signed-off-by: Rakib Mullick <rakib.mullick@gmail.com>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/1327422836.27181.5.camel@localhost.localdomain
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2012-01-27 13:28:53 +01:00
Bharata B Rao
88ebc08ea9 sched: Add documentation for bandwidth control
Basic description of usage and effect for CFS Bandwidth Control.

Signed-off-by: Bharata B Rao <bharata@linux.vnet.ibm.com>
Signed-off-by: Paul Turner <pjt@google.com>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/20110721184758.498036116@google.com
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2011-08-14 12:03:58 +02:00
Jiri Kosina
b7e9c223be Merge branch 'master' into for-next
Sync with Linus' tree to be able to apply pending patches that
are based on newer code already present upstream.
2011-07-11 14:15:55 +02:00
Jörg Sommer
f6e07d3807 Documentation: update cgroupfs mount point
According to commit 676db4af04 ("cgroupfs: create /sys/fs/cgroup to
mount cgroupfs on") the canonical mountpoint for the cgroup filesystem
is /sys/fs/cgroup.  Hence, this should be used in the documentation.

Signed-off-by: Jörg Sommer <joerg@alea.gnuu.de>
Acked-by: Paul Menage <menage@google.com>
Signed-off-by: Randy Dunlap <randy.dunlap@oracle.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-06-15 21:52:50 -07:00
Wanlong Gao
25eb650a69 doc: fix wrong arch/i386 references
Change all "arch/i386" to "arch/x86" in Documentaion/,
since the directory has changed.

Also update the files which have changed their filename
in the meantime accordingly.

Signed-off-by: Wanlong Gao <wanlong.gao@gmail.com>
[jkosina@suse.cz: reword changelog]
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
2011-06-13 13:43:05 +02:00
Borislav Petkov
e2495b5773 sched, doc: Beef up load balancing description
Correct all function names pertaining to load balancing and explain
shortly how load balancing is performed.

Signed-off-by: Borislav Petkov <bp@alien8.de>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
LKML-Reference: <1301241433-3790-1-git-send-email-bp@alien8.de>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2011-03-31 13:00:35 +02:00
Borislav Petkov
1232d6132a sched, doc: Update sched-design-CFS.txt
Correct ->dequeue_tree() thinko into sched_class->dequeue_task
and drop all references to ->task_new() since it is obviously
gone.

Signed-off-by: Borislav Petkov <borislav.petkov@amd.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Mike Galbraith <efault@gmx.de>
LKML-Reference: <1300815978-16618-1-git-send-email-bp@amd64.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2011-03-23 14:09:41 +01:00
Javi Merino
1e1dbb259c sched, docs: Update schedstats documentation to version 15
Version 15 of schedstats was introduced in:

   67aa0f767a: sched: remove unused fields from struct rq

and removed three unused counters in sched_yield(). Update
the documentation.

Signed-off-by: Javi Merino <cibervicho@gmail.com>
Cc: henrix@sapo.pt
Cc: rdunlap@xenotime.net
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Mike Galbraith <efault@gmx.de>
LKML-Reference: <1296515496-8229-1-git-send-email-cibervicho@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2011-02-01 09:07:13 +01:00
Michael Witten
1ed7c2077a Docs: typo: Complete -> Completely
Signed-off-by: Michael Witten <mfwitten@gmail.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
2010-11-02 22:47:39 -04:00
Li Zefan
25c2d55c00 sched: Remove USER_SCHED from documentation
USER_SCHED has been removed, so update the documentation
accordingly.

Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Acked-by: Serge E. Hallyn <serue@us.ibm.com>
LKML-Reference: <4BA9A07E.8070508@cn.fujitsu.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2010-04-02 20:12:01 +02:00
Wolfram Sang
d4ec36bac3 sched: Documentation/sched-rt-group: Fix style issues & bump version
- add missing closing bracket
- fix two 80-chars issues (as the rest of the document adheres to it)
- bump a reference to kernel version, so the document does not feel aged

Signed-off-by: Wolfram Sang <w.sang@pengutronix.de>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
LKML-Reference: <1245580359-4465-1-git-send-email-w.sang@pengutronix.de>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-06-21 13:12:46 +02:00
Matt LaPlante
19f5946001 trivial: Miscellaneous documentation typo fixes
Fix various typos in documentation txts.

Signed-off-by: Matt LaPlante <kernel1@cyberdogtech.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
2009-06-12 18:01:47 +02:00
GeunSik Lim
f04d82b7e0 sched: fix typo in sched-rt-group.txt file
Fix typo about static priority's range.

    Kernel Space                     User Space
    ===============================================================
      0(high) to  98(low)     user RT priority 99(high) to 1(low)
                              with SCHED_RR or SCHED_FIFO
    ---------------------------------------------------------------
     99                       sched_priority is not used in scheduling
                              decisions(it must be specified as 0)
    ---------------------------------------------------------------
    100(high) to 139(low)     user nice -20(high) to 19(low)
    ---------------------------------------------------------------
    140                       idle task priority
    ---------------------------------------------------------------
    * ref) http://www.kernel.org/doc/man-pages/online/pages/man2/sched_setscheduler.2.html

Signed-off-by: GeunSik Lim <geunsik.lim@samsung.com>
CC: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
LKML-Reference: <new-submission>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-05-29 16:21:09 +02:00
Peter Zijlstra
60aa605dfc sched: rt: document the risk of small values in the bandwidth settings
Thomas noted that we should disallow sysctl_sched_rt_runtime == 0 for
(!RT_GROUP) since the root group always has some RT tasks in it.

Further, update the documentation to inspire clue.

[ Impact: exclude corner-case sysctl_sched_rt_runtime value ]

Reported-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
LKML-Reference: <20090505155436.863098054@chello.nl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-05-05 20:07:57 +02:00
Thadeu Lima de Souza Cascardo
21acb9caa2 trivial: fix where cgroup documentation is not correctly referred to
cgroup documentation was moved to Documentation/cgroups/. There are some
places that still refer to Documentation/controllers/,
Documentation/cgroups.txt and Documentation/cpusets.txt. Fix those.

Signed-off-by: Thadeu Lima de Souza Cascardo <cascardo@holoscopio.com>
Reviewed-by: Li Zefan <lizf@cn.fujitsu.com>
Acked-by: Paul Menage <menage@google.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
2009-03-30 15:22:02 +02:00
Wang Chen
72fd455ba5 sched, documentation: remove old O(1) scheduler document
Since we don't have O(1) scheduler implementation anymore,
remove the legacy doc.

Signed-off-by: Wang Chen <wangchen@cn.fujitsu.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-03-02 12:02:52 +01:00
Li Zefan
45ce80fb6b cgroups: consolidate cgroup documents
Move Documentation/cpusets.txt and Documentation/controllers/* to
Documentation/cgroups/

Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Acked-by: Balbir Singh <balbir@linux.vnet.ibm.com>
Acked-by: Paul Menage <menage@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-01-15 16:39:37 -08:00
Linus Torvalds
a39b863342 Merge branch 'sched-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip
* 'sched-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: (31 commits)
  sched: fix warning in fs/proc/base.c
  schedstat: consolidate per-task cpu runtime stats
  sched: use RCU variant of list traversal in for_each_leaf_rt_rq()
  sched, cpuacct: export percpu cpuacct cgroup stats
  sched, cpuacct: refactoring cpuusage_read / cpuusage_write
  sched: optimize update_curr()
  sched: fix wakeup preemption clock
  sched: add missing arch_update_cpu_topology() call
  sched: let arch_update_cpu_topology indicate if topology changed
  sched: idle_balance() does not call load_balance_newidle()
  sched: fix sd_parent_degenerate on non-numa smp machine
  sched: add uid information to sched_debug for CONFIG_USER_SCHED
  sched: move double_unlock_balance() higher
  sched: update comment for move_task_off_dead_cpu
  sched: fix inconsistency when redistribute per-cpu tg->cfs_rq shares
  sched/rt: removed unneeded defintion
  sched: add hierarchical accounting to cpu accounting controller
  sched: include group statistics in /proc/sched_debug
  sched: rename SCHED_NO_NO_OMIT_FRAME_POINTER => SCHED_OMIT_FRAME_POINTER
  sched: clean up SCHED_CPUMASK_ALLOC
  ...
2008-12-28 12:27:58 -08:00
Serge E. Hallyn
94d6a5f734 user namespaces: document CFS behavior
Documented the currently bogus state of support for CFS user groups with
user namespaces.  In particular, all users in a user namespace should be
children of the user which created the user namespace.  This is yet to
be implemented.

Signed-off-by: Serge E. Hallyn <serue@us.ibm.com>
Acked-by: Dhaval Giani <dhaval@linux.vnet.ibm.com>

Signed-off-by: Serge E. Hallyn <serue@us.ibm.com>
Signed-off-by: James Morris <jmorris@namei.org>
2008-12-09 09:25:53 +11:00
Randy Dunlap
90080bf4b8 sched, documentation: update scheduler header file paths
Impact: update documentation

Update Documentation/scheduler/ files to reflect changed header files locations.

Signed-off-by: Randy Dunlap <randy.dunlap@oracle.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-11-06 09:02:15 +01:00
Li Zefan
a0e5ebdc1d sched: remove sched-design.txt from 00-INDEX
Impact: remove stale documentation reference

sched-design.txt has been removed.

Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-10-30 11:37:58 +01:00
Jiri Kosina
4078e359c4 sched: fix documentation reference for sched_min_granularity_ns
Impact: documentation fix

sched-design-CFS.txt wrongly references sched_granularity_ns sysctl,
as its name in fact is sched_min_granularity_ns.

Signed-off-by: Jiri Kosina <jkosina@suse.cz>
Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-10-27 18:49:19 +01:00
Martin Steigerwald
1a73ef6ac3 CFS scheduler: documentation about scheduling policies
The documentation about the CFS scheduler is scarse when it comes to
scheduling policies. This patch adds a chapter about the scheduling
policies it supports. Peter Zijlstra provided most of the information
for it in

http://marc.info/?l=linux-kernel&m=122210038326356&w=2

Signed-off-by: Martin Steigerwald <ms@teamix.de>
Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-09-23 13:49:44 +02:00
Claudio Scordino
f58e2c33ff sched: new documentation about CFS
Rewrite of the CFS documentation - because the old one was sorely
out-dated.

Signed-off-by: Claudio Scordino <claudio@evidence.eu.com>
Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-08-21 08:17:24 +02:00
Hiroshi Shimamoto
f7d62364b2 sched: fix typo in Documentation/scheduler/sched-rt-group.txt
Fix minor typos.

Signed-off-by: Hiroshi Shimamoto <h-shimamoto@ct.jp.nec.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-06-18 12:34:15 +02:00
Gautham R Shenoy
e29c98d12b sched: update the sched-domains debug documentation
SCHED_DOMAIN_DEBUG mentioned in the Documentation for sched-domains
for enabling sched-domains debugging doesn't exist anymore.

Update the documentation to reflect the correct way of enabling
sched-domain debugging.

Signed-off-by: Gautham R Shenoy <ego@in.ibm.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-06-06 15:19:39 +02:00
Ingo Molnar
733a0771df sched: remove old sched doc
Fabio Checconi noticed that Documentation/scheduler/sched-design.txt was
a stale copy of the old scheduler. Remove it.

Reported-by: Fabio Checconi <fabio@gandalf.sssup.it>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-05-05 23:56:17 +02:00
Viktor Radnai
b9b158fe1c sched: better rt-group documentation
Viktor was nice enough to enhance the document based on my replies to
his questions on the subject.

Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-04-19 19:45:01 +02:00
J. Bruce Fields
d396c5f158 Move sched-rt-group.txt to scheduler/
Signed-off-by: J. Bruce Fields <bfields@citi.umich.edu>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
2008-04-11 13:21:03 -06:00
Masatake YAMATO
9afa802ff5 Typo in Documentation/scheduler/sched-stats.txt
I have found a very small typo in Documentation/scheduler/sched-stats.txt.
See the end of this mail.

Signed-off-by: Masatake YAMATO <yamato@redhat.com>
Cc: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-03-10 18:01:19 -07:00
J. Bruce Fields
9b8eae7248 Documentation: create new scheduler/ subdirectory
The top-level Documentation/ directory is unmanageably large, so we
should take any obvious opportunities to move stuff into subdirectories.
These sched-*.txt files seem an obvious easy case.

Signed-off-by: J. Bruce Fields <bfields@citi.umich.edu>
Cc: Ingo Molnar <mingo@elte.hu>
Acked-by: Randy Dunlap <randy.dunlap@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-02-07 08:42:17 -08:00