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authorLinus Torvalds <torvalds@linux-foundation.org>2009-07-16 13:18:29 -0400
committerLinus Torvalds <torvalds@linux-foundation.org>2009-07-16 13:18:29 -0400
commit4b0a84043e0c14088958fddb62f416d050368011 (patch)
treecf5df6cef66a178c35e335240a756798caf2c399 /Documentation
parent63f7a330014ad29b662638caabd8e96fe945b9ed (diff)
parentd07387b490b1c43bfcb9f3900faf96f2dafb2630 (diff)
Merge branch 'sched-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/peterz/linux-2.6-sched
* 'sched-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/peterz/linux-2.6-sched: sched: Fix bug in SCHED_IDLE interaction with group scheduling sched: Fix rt_rq->pushable_tasks initialization in init_rt_rq() sched: Reset sched stats on fork() sched_rt: Fix overload bug on rt group scheduling sched: Documentation/sched-rt-group: Fix style issues & bump version
Diffstat (limited to 'Documentation')
-rw-r--r--Documentation/scheduler/sched-rt-group.txt13
1 files changed, 7 insertions, 6 deletions
diff --git a/Documentation/scheduler/sched-rt-group.txt b/Documentation/scheduler/sched-rt-group.txt
index 1df7f9cdab05..86eabe6c3419 100644
--- a/Documentation/scheduler/sched-rt-group.txt
+++ b/Documentation/scheduler/sched-rt-group.txt
@@ -73,7 +73,7 @@ The remaining CPU time will be used for user input and other tasks. Because
73realtime tasks have explicitly allocated the CPU time they need to perform 73realtime tasks have explicitly allocated the CPU time they need to perform
74their tasks, buffer underruns in the graphics or audio can be eliminated. 74their tasks, buffer underruns in the graphics or audio can be eliminated.
75 75
76NOTE: the above example is not fully implemented as of yet (2.6.25). We still 76NOTE: the above example is not fully implemented yet. We still
77lack an EDF scheduler to make non-uniform periods usable. 77lack an EDF scheduler to make non-uniform periods usable.
78 78
79 79
@@ -140,14 +140,15 @@ The other option is:
140 140
141.o CONFIG_CGROUP_SCHED (aka "Basis for grouping tasks" = "Control groups") 141.o CONFIG_CGROUP_SCHED (aka "Basis for grouping tasks" = "Control groups")
142 142
143This uses the /cgroup virtual file system and "/cgroup/<cgroup>/cpu.rt_runtime_us" 143This uses the /cgroup virtual file system and
144to control the CPU time reserved for each control group instead. 144"/cgroup/<cgroup>/cpu.rt_runtime_us" to control the CPU time reserved for each
145control group instead.
145 146
146For more information on working with control groups, you should read 147For more information on working with control groups, you should read
147Documentation/cgroups/cgroups.txt as well. 148Documentation/cgroups/cgroups.txt as well.
148 149
149Group settings are checked against the following limits in order to keep the configuration 150Group settings are checked against the following limits in order to keep the
150schedulable: 151configuration schedulable:
151 152
152 \Sum_{i} runtime_{i} / global_period <= global_runtime / global_period 153 \Sum_{i} runtime_{i} / global_period <= global_runtime / global_period
153 154
@@ -189,7 +190,7 @@ Implementing SCHED_EDF might take a while to complete. Priority Inheritance is
189the biggest challenge as the current linux PI infrastructure is geared towards 190the biggest challenge as the current linux PI infrastructure is geared towards
190the limited static priority levels 0-99. With deadline scheduling you need to 191the limited static priority levels 0-99. With deadline scheduling you need to
191do deadline inheritance (since priority is inversely proportional to the 192do deadline inheritance (since priority is inversely proportional to the
192deadline delta (deadline - now). 193deadline delta (deadline - now)).
193 194
194This means the whole PI machinery will have to be reworked - and that is one of 195This means the whole PI machinery will have to be reworked - and that is one of
195the most complex pieces of code we have. 196the most complex pieces of code we have.