Message-ID: <20231002115553.3007-4-chrubis@suse.cz>
Date:   Mon,  2 Oct 2023 13:55:53 +0200
From:   Cyril Hrubis <chrubis@...e.cz>
To:     Ingo Molnar <mingo@...hat.com>,
        Peter Zijlstra <peterz@...radead.org>,
        Juri Lelli <juri.lelli@...hat.com>,
        Vincent Guittot <vincent.guittot@...aro.org>,
        Dietmar Eggemann <dietmar.eggemann@....com>,
        Steven Rostedt <rostedt@...dmis.org>,
        Ben Segall <bsegall@...gle.com>, Mel Gorman <mgorman@...e.de>,
        Daniel Bristot de Oliveira <bristot@...hat.com>,
        Valentin Schneider <vschneid@...hat.com>,
        linux-kernel@...r.kernel.org, Jonathan Corbet <corbet@....net>,
        linux-doc@...r.kernel.org
Cc:     ltp@...ts.linux.it, Cyril Hrubis <chrubis@...e.cz>
Subject: [PATCH v3 3/3] docs: scheduler-rt: Use real-time instead of realtime

Signed-off-by: Cyril Hrubis <chrubis@...e.cz>
---
 Documentation/scheduler/sched-rt-group.rst | 34 +++++++++++-----------
 1 file changed, 17 insertions(+), 17 deletions(-)

diff --git a/Documentation/scheduler/sched-rt-group.rst b/Documentation/scheduler/sched-rt-group.rst
index a16bee8f74c2..d685609ed3d7 100644
--- a/Documentation/scheduler/sched-rt-group.rst
+++ b/Documentation/scheduler/sched-rt-group.rst
@@ -39,10 +39,10 @@ Most notable:
 1.1 The problem
 ---------------
 
-Realtime scheduling is all about determinism, a group has to be able to rely on
+Real-time scheduling is all about determinism, a group has to be able to rely on
 the amount of bandwidth (eg. CPU time) being constant. In order to schedule
-multiple groups of realtime tasks, each group must be assigned a fixed portion
-of the CPU time available.  Without a minimum guarantee a realtime group can
+multiple groups of real-time tasks, each group must be assigned a fixed portion
+of the CPU time available.  Without a minimum guarantee a real-time group can
 obviously fall short. A fuzzy upper limit is of no use since it cannot be
 relied upon. Which leaves us with just the single fixed portion.
 
@@ -50,14 +50,14 @@ relied upon. Which leaves us with just the single fixed portion.
 ----------------
 
 CPU time is divided by means of specifying how much time can be spent running
-in a given period. We allocate this "run time" for each realtime group which
-the other realtime groups will not be permitted to use.
+in a given period. We allocate this "run time" for each real-time group which
+the other real-time groups will not be permitted to use.
 
-Any time not allocated to a realtime group will be used to run normal priority
+Any time not allocated to a real-time group will be used to run normal priority
 tasks (SCHED_OTHER). Any allocated run time not used will also be picked up by
 SCHED_OTHER.
 
-Let's consider an example: a frame fixed realtime renderer must deliver 25
+Let's consider an example: a frame fixed real-time renderer must deliver 25
 frames a second, which yields a period of 0.04s per frame. Now say it will also
 have to play some music and respond to input, leaving it with around 80% CPU
 time dedicated for the graphics. We can then give this group a run time of 0.8
@@ -70,7 +70,7 @@ needs only about 3% CPU time to do so, it can do with a 0.03 * 0.005s =
 of 0.00015s.
 
 The remaining CPU time will be used for user input and other tasks. Because
-realtime tasks have explicitly allocated the CPU time they need to perform
+real-time tasks have explicitly allocated the CPU time they need to perform
 their tasks, buffer underruns in the graphics or audio can be eliminated.
 
 NOTE: the above example is not fully implemented yet. We still
@@ -90,12 +90,12 @@ The system wide settings are configured under the /proc virtual file system:
   The scheduling period that is equivalent to 100% CPU bandwidth.
 
 /proc/sys/kernel/sched_rt_runtime_us:
-  A global limit on how much time realtime scheduling may use. This is always
+  A global limit on how much time real-time scheduling may use. This is always
   less or equal to the period_us, as it denotes the time allocated from the
-  period_us for the realtime tasks. Even without CONFIG_RT_GROUP_SCHED enabled,
-  this will limit time reserved to realtime processes. With
+  period_us for the real-time tasks. Even without CONFIG_RT_GROUP_SCHED enabled,
+  this will limit time reserved to real-time processes. With
   CONFIG_RT_GROUP_SCHED=y it signifies the total bandwidth available to all
-  realtime groups.
+  real-time groups.
 
   * Time is specified in us because the interface is s32. This gives an
     operating range from 1us to about 35 minutes.
@@ -110,7 +110,7 @@ The system wide settings are configured under the /proc virtual file system:
 The default values for sched_rt_period_us (1000000 or 1s) and
 sched_rt_runtime_us (950000 or 0.95s).  This gives 0.05s to be used by
 SCHED_OTHER (non-RT tasks). These defaults were chosen so that a run-away
-realtime tasks will not lock up the machine but leave a little time to recover
+real-time tasks will not lock up the machine but leave a little time to recover
 it.  By setting runtime to -1 you'd get the old behaviour back.
 
 By default all bandwidth is assigned to the root group and new groups get the
@@ -118,10 +118,10 @@ period from /proc/sys/kernel/sched_rt_period_us and a run time of 0. If you
 want to assign bandwidth to another group, reduce the root group's bandwidth
 and assign some or all of the difference to another group.
 
-Realtime group scheduling means you have to assign a portion of total CPU
-bandwidth to the group before it will accept realtime tasks. Therefore you will
-not be able to run realtime tasks as any user other than root until you have
-done that, even if the user has the rights to run processes with realtime
+Real-time group scheduling means you have to assign a portion of total CPU
+bandwidth to the group before it will accept real-time tasks. Therefore you will
+not be able to run real-time tasks as any user other than root until you have
+done that, even if the user has the rights to run processes with real-time
 priority!
 
 
-- 
2.41.0

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