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-rw-r--r--erts/doc/src/erl.xml49
1 files changed, 38 insertions, 11 deletions
diff --git a/erts/doc/src/erl.xml b/erts/doc/src/erl.xml
index 528a2d95aa..e737727941 100644
--- a/erts/doc/src/erl.xml
+++ b/erts/doc/src/erl.xml
@@ -1,4 +1,4 @@
-<?xml version="1.0" encoding="latin1" ?>
+<?xml version="1.0" encoding="utf-8" ?>
<!DOCTYPE comref SYSTEM "comref.dtd">
<comref>
@@ -941,6 +941,10 @@
when schedulers frequently run out of work. When disabled,
the frequency with which schedulers run out of work will
not be taken into account by the load balancing logic.
+ <br/>&nbsp;&nbsp;<c>+scl false</c> is similar to
+ <seealso marker="#+sub">+sub true</seealso> with the difference
+ that <c>+sub true</c> also will balance scheduler utilization
+ between schedulers.
</p>
</item>
<tag><marker id="+sct"><c>+sct CpuTopology</c></marker></tag>
@@ -1087,6 +1091,29 @@
documentation of the <seealso marker="#+sbt">+sbt</seealso> flag.
</p>
</item>
+ <tag><marker id="+sub"><c>+sub true|false</c></marker></tag>
+ <item>
+ <p>Enable or disable
+ <seealso marker="erts:erlang#statistics_scheduler_wall_time">scheduler
+ utilization</seealso> balancing of load. By default scheduler
+ utilization balancing is disabled and instead scheduler
+ compaction of load is enabled which will strive for a load
+ distribution which causes as many scheduler threads as possible
+ to be fully loaded (i.e., not run out of work). When scheduler
+ utilization balancing is enabled the system will instead try to
+ balance scheduler utilization between schedulers. That is,
+ strive for equal scheduler utilization on all schedulers.
+ <br/>&nbsp;&nbsp;&nbsp;<c>+sub true</c> is only supported on
+ systems where the runtime system detects and use a monotonically
+ increasing high resolution clock. On other systems, the runtime
+ system will fail to start.
+ <br/>&nbsp;&nbsp;&nbsp;<c>+sub true</c> implies
+ <seealso marker="#+scl">+scl false</seealso>. The difference
+ between <c>+sub true</c> and <c>+scl false</c> is that
+ <c>+scl false</c> will not try to balance the scheduler
+ utilization.
+ </p>
+ </item>
<tag><marker id="+swct"><c>+sws very_eager|eager|medium|lazy|very_lazy</c></marker></tag>
<item>
<p>
@@ -1126,18 +1153,18 @@
<tag><marker id="+spp"><c>+spp Bool</c></marker></tag>
<item>
<p>Set default scheduler hint for port parallelism. If set to
- <c>true</c>, the VM will schedule port tasks when it by this can
- improve the parallelism in the system. If set to <c>false</c>,
- the VM will try to perform port tasks immediately and by this
- improve latency at the expense of parallelism. If this
- flag has not been passed, the default scheduler hint for port
- parallelism is currently <c>false</c>. The default used can be
- inspected in runtime by calling
- <seealso marker="erlang#system_info_port_parallelism">erlang:system_info(port_parallelism)</seealso>.
+ <c>true</c>, the VM will schedule port tasks when doing so will
+ improve parallelism in the system. If set to <c>false</c>, the VM
+ will try to perform port tasks immediately, improving latency at the
+ expense of parallelism. If this flag has not been passed, the
+ default scheduler hint for port parallelism is currently
+ <c>false</c>. The default used can be inspected in runtime by
+ calling <seealso
+ marker="erlang#system_info_port_parallelism">erlang:system_info(port_parallelism)</seealso>.
The default can be overriden on port creation by passing the
<seealso marker="erlang#open_port_parallelism">parallelism</seealso>
- option to
- <seealso marker="erlang#open_port/2">open_port/2</seealso></p>.
+ option to <seealso
+ marker="erlang#open_port/2">open_port/2</seealso></p>.
</item>
<tag><marker id="sched_thread_stack_size"><c><![CDATA[+sss size]]></c></marker></tag>
<item>