diff options
Diffstat (limited to 'erts/doc')
| -rw-r--r-- | erts/doc/src/erl.xml | 36 | ||||
| -rw-r--r-- | erts/doc/src/erlang.xml | 19 |
2 files changed, 51 insertions, 4 deletions
diff --git a/erts/doc/src/erl.xml b/erts/doc/src/erl.xml index bb741c7836..df80142ce1 100644 --- a/erts/doc/src/erl.xml +++ b/erts/doc/src/erl.xml @@ -41,6 +41,26 @@ to scroll back to text which has scrolled off the screen. The <c><![CDATA[erl]]></c> program must be used, however, in pipelines or if you want to redirect standard input or output.</p> + <note><p>As of ERTS version 5.8 (OTP-R14A) 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> + 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="#+sbt">+sbtu</seealso> command line argument, + or by invoking + <seealso marker="erlang#system_flag_scheduler_bind_type">erlang:system_flag(scheduler_bind_type, + unbound)</seealso>.</p> + </note> </description> <funcs> <func> @@ -657,6 +677,22 @@ that the <c>+sct</c> flag may have to be passed before the <c>+sbt</c> flag on the command line (in case no CPU topology has been automatically detected).</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 advised + to unbind the schedulers using the <c>+sbtu</c> command line + argument, or by invoking + <seealso marker="erlang#system_flag_scheduler_bind_type">erlang:system_flag(scheduler_bind_type, + unbound)</seealso>.</p> <p>For more information, see <seealso marker="erlang#system_flag_scheduler_bind_type">erlang:system_flag(scheduler_bind_type, SchedulerBindType)</seealso>. </p> 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> |