From 97fa9fe68af5990a8ef7a71ccb7fc235d20a2c04 Mon Sep 17 00:00:00 2001
From: Rickard Green <rickard@erlang.org>
Date: Thu, 3 Jun 2010 12:43:57 +0000
Subject: OTP-8666 Enable automatic binding of schedulers when possible

The runtime system will by default bind schedulers to logical processors
using the default_bind bind type if the amount of schedulers are at least
equal to the amount of logical processors configured, binding of schedulers
is supported, and a CPU topology is available at startup.

NOTE: If the Erlang runtime system is the only operating system process
that binds threads to logical processors, this improves the performance of
the runtime system. However, if other operating system processes (as for
example another Erlang runtime system) also bind threads to logical
processors, there might be a performance penalty instead. If this is the
case you, are are advised to unbind the schedulers using the <seealso
marker="erl#+sbt">+sbtu</seealso> command line argument, or by invoking
<seealso
marker="erlang#system_flag_scheduler_bind_type">erlang:system_flag(schedule
r_bind_type, unbound)</seealso>.
---
 erts/doc/src/erlang.xml | 19 +++++++++++++++----
 1 file changed, 15 insertions(+), 4 deletions(-)

(limited to 'erts/doc/src/erlang.xml')

diff --git a/erts/doc/src/erlang.xml b/erts/doc/src/erlang.xml
index c3c0dd77d7..c8fe7b4bd2 100644
--- a/erts/doc/src/erlang.xml
+++ b/erts/doc/src/erlang.xml
@@ -5156,10 +5156,21 @@ true</pre>
 	       For more information on how to define the CPU topology, see 
 	       <seealso marker="#system_flag_cpu_topology">erlang:system_flag(cpu_topology, CpuTopology)</seealso>.
 	    </p>
-	    <p><em>NOTE:</em> If other programs on the system have bound
-	       to processors, e.g. another Erlang runtime system, you
-	       may lose performance when binding schedulers. Therefore,
-	       schedulers are by default not bound.</p>
+            <p>The runtime system will by default bind schedulers to logical
+	       processors using the <c>default_bind</c> bind type if the amount
+	       of schedulers are at least equal to the amount of logical
+	       processors configured, binding of schedulers is supported,
+	       and a CPU topology is available at startup.
+	    </p>
+	    <p><em>NOTE:</em> If the Erlang runtime system is the only
+	       operating system process that binds threads to logical processors,
+	       this improves the performance of the runtime system. However,
+	       if other operating system processes (as for example another Erlang
+	       runtime system) also bind threads to logical processors, there
+	       might be a performance penalty instead. If this is the case you,
+	       are are advised to unbind the schedulers using the
+	       <seealso marker="erl#+sbt">+sbtu</seealso> command line argument,
+	       or <c>erlang:system_flag(scheduler_bind_type, unbound)</c>.</p>
 	    <p>Schedulers can be bound in different ways. The <c>How</c>
 	       argument determines how schedulers are bound. <c>How</c> can
 	       currently be one of:</p>
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