diff options
Diffstat (limited to 'erts/doc')
| -rw-r--r-- | erts/doc/src/erl.xml | 155 | ||||
| -rw-r--r-- | erts/doc/src/erlang.xml | 164 |
2 files changed, 168 insertions, 151 deletions
diff --git a/erts/doc/src/erl.xml b/erts/doc/src/erl.xml index d0a0ceaeba..9fb718e60f 100644 --- a/erts/doc/src/erl.xml +++ b/erts/doc/src/erl.xml @@ -41,25 +41,11 @@ 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><p>As of ERTS version 5.9 (OTP-R15B) the runtime system will by + default <em>not</em> bind schedulers to logical processors. + For more information see documentation of the + <seealso marker="#+sbt">+sbt</seealso> system flag. + </p> </note> </description> <funcs> @@ -679,41 +665,66 @@ </p> <taglist> <tag><c>u</c></tag> - <item><p>Same as - <seealso marker="erlang#system_flag_scheduler_bind_type">erlang:system_flag(scheduler_bind_type, unbound)</seealso>. - </p></item> + <item> + <p><c>unbound</c> - Schedulers will not be bound to logical + processors, i.e., the operating system decides where the + scheduler threads execute, and when to migrate them. This is + the default.</p> + </item> <tag><c>ns</c></tag> - <item><p>Same as - <seealso marker="erlang#system_flag_scheduler_bind_type">erlang:system_flag(scheduler_bind_type, no_spread)</seealso>. - </p></item> + <item> + <p><c>no_spread</c> - Schedulers with close scheduler + identifiers will be bound as close as possible in hardware.</p> + </item> <tag><c>ts</c></tag> - <item><p>Same as - <seealso marker="erlang#system_flag_scheduler_bind_type">erlang:system_flag(scheduler_bind_type, thread_spread)</seealso>. - </p></item> + <item> + <p><c>thread_spread</c> - Thread refers to hardware threads + (e.g. Intels hyper-threads). Schedulers with low scheduler + identifiers, will be bound to the first hardware thread of + each core, then schedulers with higher scheduler identifiers + will be bound to the second hardware thread of each core, + etc.</p> + </item> <tag><c>ps</c></tag> - <item><p>Same as - <seealso marker="erlang#system_flag_scheduler_bind_type">erlang:system_flag(scheduler_bind_type, processor_spread)</seealso>. - </p></item> + <item> + <p><c>processor_spread</c> - Schedulers will be spread like + <c>thread_spread</c>, but also over physical processor chips.</p> + </item> <tag><c>s</c></tag> - <item><p>Same as - <seealso marker="erlang#system_flag_scheduler_bind_type">erlang:system_flag(scheduler_bind_type, spread)</seealso>. - </p></item> + <item> + <p><c>spread</c> - Schedulers will be spread as much as + possible.</p> + </item> <tag><c>nnts</c></tag> - <item><p>Same as - <seealso marker="erlang#system_flag_scheduler_bind_type">erlang:system_flag(scheduler_bind_type, no_node_thread_spread)</seealso>. - </p></item> + <item> + <p><c>no_node_thread_spread</c> - Like <c>thread_spread</c>, + but if multiple NUMA (Non-Uniform Memory Access) nodes exists, + schedulers will be spread over one NUMA node at a time, + i.e., all logical processors of one NUMA node will be bound + to schedulers in sequence.</p> + </item> <tag><c>nnps</c></tag> - <item><p>Same as - <seealso marker="erlang#system_flag_scheduler_bind_type">erlang:system_flag(scheduler_bind_type, no_node_processor_spread)</seealso>. - </p></item> + <item> + <p><c>no_node_processor_spread</c> - Like + <c>processor_spread</c>, but if multiple NUMA nodes exists, + schedulers will be spread over one NUMA node at a time, i.e., + all logical processors of one NUMA node will be bound to + schedulers in sequence.</p> + </item> <tag><c>tnnps</c></tag> - <item><p>Same as - <seealso marker="erlang#system_flag_scheduler_bind_type">erlang:system_flag(scheduler_bind_type, thread_no_node_processor_spread)</seealso>. - </p></item> + <item> + <p><c>thread_no_node_processor_spread</c> - A combination of + <c>thread_spread</c>, and <c>no_node_processor_spread</c>. + Schedulers will be spread over hardware threads across NUMA + nodes, but schedulers will only be spread over processors + internally in one NUMA node at a time.</p> + </item> <tag><c>db</c></tag> - <item><p>Same as - <seealso marker="erlang#system_flag_scheduler_bind_type">erlang:system_flag(scheduler_bind_type, default_bind)</seealso>. - </p></item> + <item> + <p><c>default_bind</c> - Binds schedulers the default way. + Currently the default is <c>thread_no_node_processor_spread</c> + (which might change in the future).</p> + </item> </taglist> <p>Binding of schedulers is currently only supported on newer Linux, Solaris, FreeBSD, and Windows systems.</p> @@ -725,24 +736,34 @@ 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>The runtime system will by default <em>not</em> bind schedulers + to logical processors. </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><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. In some cases this performance penalty might be + severe. If this is the case, you are advised to not + bind the schedulers.</p> + <p>How schedulers are bound matters. For example, in + situations when there are fewer running processes than + schedulers online, the runtime system tries to migrate + processes to schedulers with low scheduler identifiers. + The more the schedulers are spread over the hardware, + the more resources will be available to the runtime + system in such situations. + </p> + <p> + <em>NOTE:</em> If a scheduler fails to bind, this + will often be silently ignored. This since it isn't always + possible to verify valid logical processor identifiers. If + an error is reported, it will be reported to the + <c>error_logger</c>. If you want to verify that the + schedulers actually have bound as requested, call + <seealso marker="erlang#system_info_scheduler_bindings">erlang:system_info(scheduler_bindings)</seealso>. </p> </item> <tag><marker id="+scl"><c>+scl true|false</c></marker></tag> @@ -773,6 +794,12 @@ <item><c><![CDATA[<IdDefs> = <LogicalIds><ThreadIds><CoreIds><ProcessorIds><NodeIds> | <LogicalIds><ThreadIds><CoreIds><NodeIds><ProcessorIds>]]></c></item> <item><c><![CDATA[CpuTopology = <IdDefs>:<IdDefs> | <IdDefs>]]></c></item> </list> + <p>Set a user defined CPU topolgy. The user defined + CPU topology will override any automatically detected + CPU topology. The CPU topology is used when + <seealso marker="#+sbt">binding schedulers to logical + processors</seealso>. + </p> <p>Upper-case letters signify real identifiers and lower-case letters signify fake identifiers only used for description of the topology. Identifiers passed as real identifiers may @@ -872,7 +899,7 @@ how the real CPU topology looks like is likely to decrease the performance of the runtime system.</p> <p>For more information, see - <seealso marker="erlang#system_flag_cpu_topology">erlang:system_flag(cpu_topology, CpuTopology)</seealso>.</p> + <seealso marker="erlang#system_info_cpu_topology">erlang:system_info(cpu_topology)</seealso>.</p> </item> <tag><marker id="+swt"><c>+swt very_low|low|medium|high|very_high</c></marker></tag> <item> diff --git a/erts/doc/src/erlang.xml b/erts/doc/src/erlang.xml index 2ea144eb3f..42a4e6a999 100644 --- a/erts/doc/src/erlang.xml +++ b/erts/doc/src/erlang.xml @@ -5069,6 +5069,14 @@ true</pre> <v>Flag, Value, OldValue -- see below</v> </type> <desc> + <warning> + <p>The + <seealso marker="#system_flag_cpu_topology">cpu_topology</seealso>, + and + <seealso marker="#system_flag_scheduler_bind_type">scheduler_bind_type</seealso> + <c>Flag</c>s are <em>deprecated</em> and have been scheduled for + removal in erts-5.10/OTP-R16.</p> + </warning> <p>Sets various system properties of the Erlang node. Returns the old value of the flag.</p> <taglist> @@ -5079,6 +5087,12 @@ true</pre> </item> <tag><marker id="system_flag_cpu_topology"><c>erlang:system_flag(cpu_topology, CpuTopology)</c></marker></tag> <item> + <p><em>NOTE:</em> This argument is <em>deprecated</em> and + scheduled for removal in erts-5.10/OTP-R16. Instead of using + this argument you are advised to use the <c>erl</c> command + line argument <seealso marker="erts:erl#+sct">+sct</seealso>. + When this argument has been removed a final CPU topology to use + will be determined at emulator boot time.</p> <p>Sets the user defined <c>CpuTopology</c>. The user defined CPU topology will override any automatically detected CPU topology. By passing <c>undefined</c> as <c>CpuTopology</c> @@ -5093,15 +5107,15 @@ true</pre> to rebind according to the new CPU topology. </p> <p>The user defined CPU topology can also be set by passing - the <seealso marker="erl#+sct">+sct</seealso> command + the <seealso marker="erts:erl#+sct">+sct</seealso> command line argument to <c>erl</c>. </p> <p>For information on the <c>CpuTopology</c> type and more, see the documentation of <seealso marker="#system_info_cpu_topology">erlang:system_info(cpu_topology)</seealso>, - the <c>erl</c> <seealso marker="erl#+sct">+sct</seealso> - emulator flag, and - <seealso marker="#system_flag_scheduler_bind_type">erlang:system_flag(scheduler_bind_type, How)</seealso>. + and the <c>erl</c> <seealso marker="erts:erl#+sct">+sct</seealso> + and <seealso marker="erts:erl#+sbt">+sbt</seealso> + command line flags. </p> </item> <tag><c>erlang:system_flag(fullsweep_after, Number)</c></tag> @@ -5177,6 +5191,12 @@ true</pre> </item> <tag><marker id="system_flag_scheduler_bind_type"><c>erlang:system_flag(scheduler_bind_type, How)</c></marker></tag> <item> + <p><em>NOTE:</em> This argument is <em>deprecated</em> and + scheduled for removal in erts-5.10/OTP-R16. Instead of using + this argument you are advised to use the <c>erl</c> command + line argument <seealso marker="erts:erl#+sbt">+sbt</seealso>. + When this argument has been removed a final scheduler bind type + to use will be determined at emulator boot time.</p> <p>Controls if and how schedulers are bound to logical processors.</p> <p>When <c>erlang:system_flag(scheduler_bind_type, How)</c> is @@ -5198,93 +5218,61 @@ true</pre> the CPU topology needs to be known. If the runtime system fails to automatically detect the CPU topology, it can be defined. For more information on how to define the CPU topology, see - <seealso marker="#system_flag_cpu_topology">erlang:system_flag(cpu_topology, CpuTopology)</seealso>. + the <c>erl</c> <seealso marker="erts:erl#+sct">+sct</seealso> command + line flag. </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>The runtime system will by default <em>not</em> bind schedulers + to logical processors. </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> + might be a performance penalty instead. In some cases this + performance penalty might be severe. If this is the case, you + are advised to not bind the schedulers.</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> <taglist> <tag><c>unbound</c></tag> - <item> - <p>Schedulers will not be bound to logical processors, i.e., - the operating system decides where the scheduler threads - execute, and when to migrate them. This is the default.</p> - </item> + <item><p>Same as the <c>erl</c> command line argument + <seealso marker="erts:erl#+sbt">+sbt u</seealso>. + </p></item> <tag><c>no_spread</c></tag> - <item> - <p>Schedulers with close scheduler identifiers will be bound - as close as possible in hardware.</p> - </item> + <item><p>Same as the <c>erl</c> command line argument + <seealso marker="erts:erl#+sbt">+sbt ns</seealso>. + </p></item> <tag><c>thread_spread</c></tag> - <item> - <p>Thread refers to hardware threads (e.g. Intels - hyper-threads). Schedulers with low scheduler identifiers, - will be bound to the first hardware thread of each core, - then schedulers with higher scheduler identifiers will be - bound to the second hardware thread of each core, etc.</p> - </item> + <item><p>Same as the <c>erl</c> command line argument + <seealso marker="erts:erl#+sbt">+sbt ts</seealso>. + </p></item> <tag><c>processor_spread</c></tag> - <item> - <p>Schedulers will be spread like <c>thread_spread</c>, but - also over physical processor chips.</p> - </item> + <item><p>Same as the <c>erl</c> command line argument + <seealso marker="erts:erl#+sbt">+sbt ps</seealso>. + </p></item> <tag><c>spread</c></tag> - <item> - <p>Schedulers will be spread as much as possible.</p> - </item> + <item><p>Same as the <c>erl</c> command line argument + <seealso marker="erts:erl#+sbt">+sbt s</seealso>. + </p></item> <tag><c>no_node_thread_spread</c></tag> - <item> - <p>Like <c>thread_spread</c>, but if multiple NUMA - (Non-Uniform Memory Access) nodes exists, - schedulers will be spread over one NUMA node at a time, - i.e., all logical processors of one NUMA node will - be bound to schedulers in sequence.</p> - </item> + <item><p>Same as the <c>erl</c> command line argument + <seealso marker="erts:erl#+sbt">+sbt nnts</seealso>. + </p></item> <tag><c>no_node_processor_spread</c></tag> - <item> - <p>Like <c>processor_spread</c>, but if multiple NUMA - nodes exists, schedulers will be spread over one - NUMA node at a time, i.e., all logical processors of - one NUMA node will be bound to schedulers in sequence.</p> - </item> + <item><p>Same as the <c>erl</c> command line argument + <seealso marker="erts:erl#+sbt">+sbt nnps</seealso>. + </p></item> <tag><c>thread_no_node_processor_spread</c></tag> - <item> - <p>A combination of <c>thread_spread</c>, and - <c>no_node_processor_spread</c>. Schedulers will be - spread over hardware threads across NUMA nodes, but - schedulers will only be spread over processors internally - in one NUMA node at a time.</p> - </item> + <item><p>Same as the <c>erl</c> command line argument + <seealso marker="erts:erl#+sbt">+sbt tnnps</seealso>. + </p></item> <tag><c>default_bind</c></tag> - <item> - <p>Binds schedulers the default way. Currently the default - is <c>thread_no_node_processor_spread</c> (which might change - in the future).</p> - </item> + <item><p>Same as the <c>erl</c> command line argument + <seealso marker="erts:erl#+sbt">+sbt db</seealso>. + </p></item> </taglist> - <p>How schedulers are bound matters. For example, in - situations when there are fewer running processes than - schedulers online, the runtime system tries to migrate - processes to schedulers with low scheduler identifiers. - The more the schedulers are spread over the hardware, - the more resources will be available to the runtime - system in such situations. - </p> <p>The value returned equals <c>How</c> before the <c>scheduler_bind_type</c> flag was changed.</p> <p>Failure:</p> @@ -5303,15 +5291,15 @@ true</pre> </item> </taglist> <p>The scheduler bind type can also be set by passing - the <seealso marker="erl#+sbt">+sbt</seealso> command + the <seealso marker="erts:erl#+sbt">+sbt</seealso> command line argument to <c>erl</c>. </p> <p>For more information, see <seealso marker="#system_info_scheduler_bind_type">erlang:system_info(scheduler_bind_type)</seealso>, <seealso marker="#system_info_scheduler_bindings">erlang:system_info(scheduler_bindings)</seealso>, - the <c>erl</c> <seealso marker="erl#+sbt">+sbt</seealso> - emulator flag, and - <seealso marker="#system_flag_cpu_topology">erlang:system_flag(cpu_topology, CpuTopology)</seealso>. + the <c>erl</c> <seealso marker="erts:erl#+sbt">+sbt</seealso> + and <seealso marker="erts:erl#+sct">+sct</seealso> command line + flags. </p> </item> <tag><marker id="system_flag_schedulers_online"><c>erlang:system_flag(schedulers_online, SchedulersOnline)</c></marker></tag> @@ -5512,10 +5500,12 @@ true</pre> <item> <p>Returns the <c>CpuTopology</c> which currently is used by the emulator. The CPU topology is used when binding schedulers - to logical processors. The CPU topology used is the user defined - CPU topology if such exist; otherwise, the automatically - detected CPU topology if such exist. If no CPU topology - exist <c>undefined</c> is returned.</p> + to logical processors. The CPU topology used is the + <seealso marker="erlang#system_info_cpu_topology_defined">user + defined CPU topology</seealso> if such exists; otherwise, the + <seealso marker="erlang#system_info_cpu_topology_detected">automatically + detected CPU topology</seealso> if such exists. If no CPU topology + exists, <c>undefined</c> is returned.</p> <p>Types:</p> <list type="bulleted"> <item><c>CpuTopology = LevelEntryList | undefined</c></item> @@ -5562,8 +5552,8 @@ true</pre> <item> <p>Returns the user defined <c>CpuTopology</c>. For more information see the documentation of - <seealso marker="#system_flag_cpu_topology">erlang:system_flag(cpu_topology, CpuTopology)</seealso> - and the documentation of the + the <c>erl</c> <seealso marker="erts:erl#+sct">+sct</seealso> command + line flag, and the documentation of the <seealso marker="#system_info_cpu_topology">cpu_topology</seealso> argument. </p> @@ -5641,7 +5631,7 @@ true</pre> <item> <p>Returns the value of the distribution buffer busy limit in bytes. This limit can be set on startup by passing the - <seealso marker="erl#+zdbbl">+zdbbl</seealso> command line + <seealso marker="erts:erl#+zdbbl">+zdbbl</seealso> command line flag to <c>erl</c>.</p> </item> <tag><c>fullsweep_after</c></tag> @@ -5843,14 +5833,13 @@ true</pre> <p>Returns information on how user has requested schedulers to be bound or not bound.</p> <p><em>NOTE:</em> Even though user has requested - schedulers to be bound via - <seealso marker="#system_flag_scheduler_bind_type">erlang:system_flag(scheduler_bind_type, How)</seealso>, - they might have silently failed to bind. In order to - inspect actual scheduler bindings call + schedulers to be bound, they might have silently failed + to bind. In order to inspect actual scheduler bindings call <seealso marker="#system_info_scheduler_bindings">erlang:system_info(scheduler_bindings)</seealso>. </p> <p>For more information, see - <seealso marker="#system_flag_scheduler_bind_type">erlang:system_flag(scheduler_bind_type, How)</seealso>, and + the <c>erl</c> <seealso marker="erts:erl#+sbt">+sbt</seealso> + command line argument, and <seealso marker="#system_info_scheduler_bindings">erlang:system_info(scheduler_bindings)</seealso>. </p> </item> @@ -5873,7 +5862,8 @@ true</pre> <p>Note that only schedulers online can be bound to logical processors.</p> <p>For more information, see - <seealso marker="#system_flag_scheduler_bind_type">erlang:system_flag(scheduler_bind_type, How)</seealso>, + the <c>erl</c> <seealso marker="erts:erl#+sbt">+sbt</seealso> + command line argument, <seealso marker="#system_info_schedulers_online">erlang:system_info(schedulers_online)</seealso>. </p> </item> |