Commit Graph

8 Commits

Author SHA1 Message Date
Mukesh Kumar Chaurasiya a26979377b sched/doc: Update documentation for base_slice_ns and CONFIG_HZ relation
The tunable base_slice_ns is dependent on CONFIG_HZ (i.e. TICK_NSEC)
for any significant performance improvement. The reason being the
scheduler tick is not frequent enough to force preemption when
base_slice expires in case of:

           base_slice_ns < TICK_NSEC

The below data is of stress-ng:

	Number of CPU: 1
	Stressor threads: 4
	Time: 30sec

	On CONFIG_HZ=1000

	| base_slice | avg-run (msec) | context-switches |
	| ---------- | -------------- | ---------------- |
	| 3ms        | 2.914          | 10342            |
	| 6ms        | 4.857          | 6196             |
	| 9ms        | 6.754          | 4482             |
	| 12ms       | 7.872          | 3802             |
	| 22ms       | 11.294         | 2710             |
	| 32ms       | 13.425         | 2284             |

	On CONFIG_HZ=100

	| base_slice | avg-run (msec) | context-switches |
	| ---------- | -------------- | ---------------- |
	| 3ms        | 9.144          | 3337             |
	| 6ms        | 9.113          | 3301             |
	| 9ms        | 8.991          | 3315             |
	| 12ms       | 12.935         | 2328             |
	| 22ms       | 16.031         | 1915             |
	| 32ms       | 18.608         | 1622             |

	base_slice: the value of base_slice in ms
	avg-run (msec): average time of the stressor threads got on cpu before
	it got preempted
	context-switches: number of context switches for the stress-ng process

Signed-off-by: Mukesh Kumar Chaurasiya <mchauras@linux.ibm.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Cc: Randy Dunlap <rdunlap@infradead.org>
Link: https://lore.kernel.org/r/20240320173815.927637-2-mchauras@linux.ibm.com
2024-03-21 20:34:16 +01:00
Wenyu Huang 0257e5a3c2 sched/doc: Update documentation after renames and synchronize Chinese version
Update the documentation after these changes, which didn't entirely
propagate the changes:

 e23edc86b0 ("sched/fair: Rename check_preempt_curr() to wakeup_preempt()")
 03b7fad167 ("sched: Add task_struct pointer to sched_class::set_curr_task")
 2f88c8e802 ("sched/eevdf/doc: Modify the documented knob to base_slice_ns as well")

[ mingo: Reworked the changelog. ]

Signed-off-by: Wenyu Huang <huangwenyu5@huawei.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Cc: linux-kernel@vger.kernel.org
2023-11-26 16:24:48 +01:00
Shrikanth Hegde 2f88c8e802 sched/eevdf/doc: Modify the documented knob to base_slice_ns as well
After committing the scheduler to EEVDF, we renamed the 'min_granularity_ns'
sysctl to 'base_slice_ns':

   e4ec3318a1 ("sched/debug: Rename sysctl_sched_min_granularity to sysctl_sched_base_slice")

... but we forgot to rename it in the documentation. Do that now.

Fixes: e4ec3318a1 ("sched/debug: Rename sysctl_sched_min_granularity to sysctl_sched_base_slice")
Signed-off-by: Shrikanth Hegde <sshegde@linux.vnet.ibm.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: https://lore.kernel.org/r/20230824080342.543396-1-sshegde@linux.vnet.ibm.com
2023-08-24 21:31:57 +02:00
Lukasz Luba 363fd2324c docs: scheduler: Update new path for the sysctl knobs
Add missing update for the documentation bit of some scheduler knob.
The knobs have been moved to /debug/sched/ location (with adjusted names).

Signed-off-by: Lukasz Luba <lukasz.luba@arm.com>
Reviewed-by: Alex Shi <alexs@kernel.org>
Tested-by: Yanteng Si <siyanteng@loongson.cn>
Link: https://lore.kernel.org/r/20220816121907.841-1-lukasz.luba@arm.com
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
2022-09-27 13:21:42 -06:00
Kir Kolyshkin f1779d13ed docs/scheduler/sched-design-CFS: formatting fix
Fix the rendering of the paragraph. Before the fix, the first line is
rendered in bold (I'm not quite sure why) and is also separated from the
rest of the paragraph, which is rendered with an indent.

Signed-off-by: Kir Kolyshkin <kolyshkin@gmail.com>
Acked-by: Tejun Heo <tj@kernel.org>
Link: https://lore.kernel.org/r/20210120001824.385168-3-kolyshkin@gmail.com
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
2021-01-21 11:40:21 -07:00
Mauro Carvalho Chehab da82c92f11 docs: cgroup-v1: add it to the admin-guide book
Those files belong to the admin guide, so add them.

Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>
2019-07-15 11:03:02 -03:00
Linus Torvalds e9a83bd232 It's been a relatively busy cycle for docs:
- A fair pile of RST conversions, many from Mauro.  These create more
    than the usual number of simple but annoying merge conflicts with other
    trees, unfortunately.  He has a lot more of these waiting on the wings
    that, I think, will go to you directly later on.
 
  - A new document on how to use merges and rebases in kernel repos, and one
    on Spectre vulnerabilities.
 
  - Various improvements to the build system, including automatic markup of
    function() references because some people, for reasons I will never
    understand, were of the opinion that :c:func:``function()`` is
    unattractive and not fun to type.
 
  - We now recommend using sphinx 1.7, but still support back to 1.4.
 
  - Lots of smaller improvements, warning fixes, typo fixes, etc.
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Merge tag 'docs-5.3' of git://git.lwn.net/linux

Pull Documentation updates from Jonathan Corbet:
 "It's been a relatively busy cycle for docs:

   - A fair pile of RST conversions, many from Mauro. These create more
     than the usual number of simple but annoying merge conflicts with
     other trees, unfortunately. He has a lot more of these waiting on
     the wings that, I think, will go to you directly later on.

   - A new document on how to use merges and rebases in kernel repos,
     and one on Spectre vulnerabilities.

   - Various improvements to the build system, including automatic
     markup of function() references because some people, for reasons I
     will never understand, were of the opinion that
     :c:func:``function()`` is unattractive and not fun to type.

   - We now recommend using sphinx 1.7, but still support back to 1.4.

   - Lots of smaller improvements, warning fixes, typo fixes, etc"

* tag 'docs-5.3' of git://git.lwn.net/linux: (129 commits)
  docs: automarkup.py: ignore exceptions when seeking for xrefs
  docs: Move binderfs to admin-guide
  Disable Sphinx SmartyPants in HTML output
  doc: RCU callback locks need only _bh, not necessarily _irq
  docs: format kernel-parameters -- as code
  Doc : doc-guide : Fix a typo
  platform: x86: get rid of a non-existent document
  Add the RCU docs to the core-api manual
  Documentation: RCU: Add TOC tree hooks
  Documentation: RCU: Rename txt files to rst
  Documentation: RCU: Convert RCU UP systems to reST
  Documentation: RCU: Convert RCU linked list to reST
  Documentation: RCU: Convert RCU basic concepts to reST
  docs: filesystems: Remove uneeded .rst extension on toctables
  scripts/sphinx-pre-install: fix out-of-tree build
  docs: zh_CN: submitting-drivers.rst: Remove a duplicated Documentation/
  Documentation: PGP: update for newer HW devices
  Documentation: Add section about CPU vulnerabilities for Spectre
  Documentation: platform: Delete x86-laptop-drivers.txt
  docs: Note that :c:func: should no longer be used
  ...
2019-07-09 12:34:26 -07:00
Mauro Carvalho Chehab d6a3b24762 docs: scheduler: convert docs to ReST and rename to *.rst
In order to prepare to add them to the Kernel API book,
convert the files to ReST format.

The conversion is actually:
  - add blank lines and identation in order to identify paragraphs;
  - fix tables markups;
  - add some lists markups;
  - mark literal blocks;
  - adjust title markups.

At its new index.rst, let's add a :orphan: while this is not linked to
the main index.rst file, in order to avoid build warnings.

Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
2019-06-14 14:32:18 -06:00