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-rw-r--r--erts/doc/src/erl.xml22
1 files changed, 20 insertions, 2 deletions
diff --git a/erts/doc/src/erl.xml b/erts/doc/src/erl.xml
index df80142ce1..f477280a6f 100644
--- a/erts/doc/src/erl.xml
+++ b/erts/doc/src/erl.xml
@@ -603,6 +603,24 @@
<item>
<p>Force ets memory block to be moved on realloc.</p>
</item>
+ <tag><marker id="+rg"><c><![CDATA[+rg ReaderGroupsLimit]]></c></marker></tag>
+ <item>
+ <p>Limits the amount of reader groups used by read/write locks
+ optimized for read operations in the Erlang runtime system. By
+ default the reader groups limit equals 8.</p>
+ <p>When the amount of schedulers is less than or equal to the reader
+ groups limit, each scheduler has its own reader group. When the
+ amount of schedulers is larger than the reader groups limit,
+ schedulers share reader groups. Shared reader groups degrades
+ read lock and read unlock performance while a large amount of
+ reader groups degrades write lock performance, so the limit is a
+ tradeoff between performance for read operations and performance
+ for write operations. Each reader group currently consumes 64 byte
+ in each read/write lock. Also note that a runtime system using
+ shared reader groups benefits from <seealso marker="#+sbt">binding
+ schedulers to logical processors</seealso>, since the reader groups
+ are distributed better between schedulers.</p>
+ </item>
<tag><marker id="+S"><c><![CDATA[+S Schedulers:SchedulerOnline]]></c></marker></tag>
<item>
<p>Sets the amount of scheduler threads to create and scheduler
@@ -667,8 +685,8 @@
<seealso marker="erlang#system_flag_scheduler_bind_type">erlang:system_flag(scheduler_bind_type, default_bind)</seealso>.
</p></item>
</taglist>
- <p>Binding of schedulers are currently only supported on newer
- Linux and Solaris systems.</p>
+ <p>Binding of schedulers is currently only supported on newer
+ Linux, Solaris, and Windows systems.</p>
<p>If no CPU topology is available when the <c>+sbt</c> flag
is processed and <c>BindType</c> is any other type than
<c>u</c>, the runtime system will fail to start. CPU