diff options
Diffstat (limited to 'erts/doc/src/erl.xml')
| -rw-r--r-- | erts/doc/src/erl.xml | 175 |
1 files changed, 104 insertions, 71 deletions
diff --git a/erts/doc/src/erl.xml b/erts/doc/src/erl.xml index 638e88ca31..133f160dc9 100644 --- a/erts/doc/src/erl.xml +++ b/erts/doc/src/erl.xml @@ -4,7 +4,7 @@ <comref> <header> <copyright> - <year>1996</year><year>2017</year> + <year>1996</year><year>2018</year> <holder>Ericsson AB. All Rights Reserved.</holder> </copyright> <legalnotice> @@ -360,11 +360,12 @@ </item> <tag><c><![CDATA[-mode interactive | embedded]]></c></tag> <item> - <p>Indicates if the system is to load code dynamically - (<c><![CDATA[interactive]]></c>), or if all code is to be loaded - during system initialization (<c><![CDATA[embedded]]></c>); see - <seealso marker="kernel:code"><c>code(3)</c></seealso>. - Defaults to <c><![CDATA[interactive]]></c>.</p> + <p>Modules are auto loaded when they are first referenced if the + runtime system runs in <c><![CDATA[interactive]]></c> mode, which is + the default. In <c><![CDATA[embedded]]></c> mode modules are not auto + loaded. The latter is recommended when the boot script preloads all + modules, as conventionally happens in OTP releases. See + <seealso marker="kernel:code"><c>code(3)</c></seealso></p>. </item> <tag><c><![CDATA[-name Name]]></c></tag> <item> @@ -538,20 +539,6 @@ <p>Note that a distributed node will fail to start if epmd is not running.</p> </item> - <tag><marker id="smp"/><c><![CDATA[-smp [enable|auto|disable]]]></c></tag> - <item> - <p><c>-smp enable</c> and <c>-smp</c> start the Erlang runtime - system with SMP support enabled. This can fail if no runtime - system with SMP support is available. <c>-smp auto</c> starts - the Erlang runtime system with SMP support enabled if it is - available and more than one logical processor is detected. - <c>-smp disable</c> starts a runtime system without SMP support. - The runtime system without SMP support is deprecated and will - be removed in a future major release.</p> - <note> - <p>See also flag<seealso marker="#+S"><c>+S</c></seealso>.</p> - </note> - </item> <tag><c><![CDATA[-version]]></c> (emulator flag)</tag> <item> <p>Makes the emulator print its version number. The same @@ -585,7 +572,7 @@ <tag><marker id="async_thread_pool_size"/><c><![CDATA[+A size]]></c></tag> <item> <p>Sets the number of threads in async thread pool. Valid range - is 0-1024. Defaults to 10 if thread support is available.</p> + is 0-1024. Defaults to 1.</p> </item> <tag><c><![CDATA[+B [c | d | i]]]></c></tag> <item> @@ -644,14 +631,16 @@ of process heaps is destroyed by the crash dump generation.</p> <p>Option <c>+d</c> instructs the emulator to produce only a core dump and no crash dump if an internal error is detected.</p> - <p>Calling <seealso marker="erlang:halt/1"> + <p>Calling <seealso marker="erlang#halt/1"> <c>erlang:halt/1</c></seealso> with a string argument still produces a crash dump. On Unix systems, sending an emulator process a <c>SIGUSR1</c> signal also forces a crash dump.</p> </item> <tag><marker id="+e"/><c><![CDATA[+e Number]]></c></tag> <item> - <p>Sets the maximum number of ETS tables.</p> + <p>Sets the maximum number of ETS tables. This limit is + <seealso marker="stdlib:ets#max_ets_tables">partially obsolete</seealso>. + </p> </item> <tag><c><![CDATA[+ec]]></c></tag> <item> @@ -776,13 +765,40 @@ <seealso marker="erlang#process_flag_message_queue_data"> <c>process_flag(message_queue_data, MQD)</c></seealso>.</p> </item> - <tag><c><![CDATA[+K true | false]]></c></tag> + <tag><marker id="+IOp"/><c>+IOp PollSets</c></tag> + <item> + <p>Sets the number of IO pollsets to use when polling for I/O. + This option is only used on platforms that support concurrent + updates of a pollset, otherwise the same number of pollsets + are used as IO poll threads. + The default is 1. + </p> + </item> + <tag><marker id="+IOt"/><c>+IOt PollThreads</c></tag> + <item> + <p>Sets the number of IO poll threads to use when polling for I/O. + The maximum number of poll threads allowed is 1024. The default is 1. + </p> + <p>A good way to check if more IO poll threads are needed is to use + <seealso marker="runtime_tools:msacc">microstate accounting</seealso> + and see what the load of the IO poll thread is. If it is high it could + be a good idea to add more threads.</p> + </item> + <tag><marker id="+IOPp"/><c>+IOPp PollSetsPercentage</c></tag> + <item> + <p>Similar to <seealso marker="#+IOp"><c>+IOp</c></seealso> but uses + percentages to set the number of IO pollsets to create, based on the + number of poll threads configured. If both <c>+IOPp</c> and <c>+IOp</c> + are used, <c>+IOPp</c> is ignored. + </p> + </item> + <tag><marker id="+IOPt"/><c>+IOPt PollThreadsPercentage</c></tag> <item> - <p>Enables or disables the kernel poll functionality if supported by - the emulator. Defaults to <c><![CDATA[false]]></c> (disabled). - If the emulator does not support kernel poll, and flag - <c><![CDATA[+K]]></c> is passed to the emulator, a warning is - issued at startup.</p> + <p>Similar to <seealso marker="#+IOt"><c>+IOt</c></seealso> but uses + percentages to set the number of IO poll threads to create, based on + the number of schedulers configured. If both <c>+IOPt</c> and + <c>+IOt</c> are used, <c>+IOPt</c> is ignored. + </p> </item> <tag><c><![CDATA[+l]]></c></tag> <item> @@ -902,7 +918,7 @@ <c><![CDATA[+S Schedulers:SchedulerOnline]]></c></tag> <item> <p>Sets the number of scheduler threads to create and scheduler threads - to set online when SMP support has been enabled. The maximum for both + to set online. The maximum for both values is 1024. If the Erlang runtime system is able to determine the number of logical processors configured and logical processors available, <c>Schedulers</c> defaults to logical processors @@ -920,8 +936,6 @@ <p>Specifying value <c>0</c> for <c>Schedulers</c> or <c>SchedulersOnline</c> resets the number of scheduler threads or scheduler threads online, respectively, to its default value.</p> - <p>This option is ignored if the emulator does not have SMP support - enabled (see flag <seealso marker="#smp"><c>-smp</c></seealso>).</p> </item> <tag><marker id="+SP"/><c><![CDATA[+SP SchedulersPercentage:SchedulersOnlinePercentage]]></c></tag> @@ -929,8 +943,8 @@ <p>Similar to <seealso marker="#+S"><c>+S</c></seealso> but uses percentages to set the number of scheduler threads to create, based on logical processors configured, and scheduler threads to set online, - based on logical processors available, when SMP support has been - enabled. Specified values must be > 0. For example, + based on logical processors available. + Specified values must be > 0. For example, <c>+SP 50:25</c> sets the number of scheduler threads to 50% of the logical processors configured, and the number of scheduler threads online to 25% of the logical processors available. @@ -945,15 +959,13 @@ and 8 logical cores available, the combination of the options <c>+S 4:4 +SP 50:25</c> (in either order) results in 2 scheduler threads (50% of 4) and 1 scheduler thread online (25% of 4).</p> - <p>This option is ignored if the emulator does not have SMP support - enabled (see flag <seealso marker="#smp"><c>-smp</c></seealso>).</p> </item> <tag><marker id="+SDcpu"/><c><![CDATA[+SDcpu DirtyCPUSchedulers:DirtyCPUSchedulersOnline]]></c></tag> <item> <p>Sets the number of dirty CPU scheduler threads to create and dirty - CPU scheduler threads to set online when threading support has been - enabled. The maximum for both values is 1024, and each value is + CPU scheduler threads to set online. + The maximum for both values is 1024, and each value is further limited by the settings for normal schedulers:</p> <list type="bulleted"> <item>The number of dirty CPU scheduler threads created cannot exceed @@ -977,16 +989,14 @@ executing on ordinary schedulers. If the amount of dirty CPU schedulers was allowed to be unlimited, dirty CPU bound jobs would potentially starve normal jobs.</p> - <p>This option is ignored if the emulator does not have threading - support enabled.</p> </item> <tag><marker id="+SDPcpu"/><c><![CDATA[+SDPcpu DirtyCPUSchedulersPercentage:DirtyCPUSchedulersOnlinePercentage]]></c></tag> <item> <p>Similar to <seealso marker="#+SDcpu"><c>+SDcpu</c></seealso> but uses percentages to set the number of dirty CPU scheduler threads to - create and the number of dirty CPU scheduler threads to set online - when threading support has been enabled. Specified values must be + create and the number of dirty CPU scheduler threads to set online. + Specified values must be > 0. For example, <c>+SDPcpu 50:25</c> sets the number of dirty CPU scheduler threads to 50% of the logical processors configured and the number of dirty CPU scheduler threads online to 25% of the @@ -1003,13 +1013,11 @@ the combination of the options <c>+SDcpu 4:4 +SDPcpu 50:25</c> (in either order) results in 2 dirty CPU scheduler threads (50% of 4) and 1 dirty CPU scheduler thread online (25% of 4).</p> - <p>This option is ignored if the emulator does not have threading - support enabled.</p> </item> <tag><marker id="+SDio"/><c><![CDATA[+SDio DirtyIOSchedulers]]></c></tag> <item> - <p>Sets the number of dirty I/O scheduler threads to create when - threading support has been enabled. Valid range is 0-1024. By + <p>Sets the number of dirty I/O scheduler threads to create. + Valid range is 0-1024. By default, the number of dirty I/O scheduler threads created is 10, same as the default number of threads in the <seealso marker="#async_thread_pool_size">async thread pool</seealso>.</p> @@ -1019,8 +1027,6 @@ expected to execute on dirty I/O schedulers. If the user should schedule CPU bound jobs on dirty I/O schedulers, these jobs might starve ordinary jobs executing on ordinary schedulers.</p> - <p>This option is ignored if the emulator does not have threading - support enabled.</p> </item> <tag><c><![CDATA[+sFlag Value]]></c></tag> <item> @@ -1151,6 +1157,26 @@ without prior notice.</p> </note> </item> + <tag><marker id="+sbwtdcpu"/> + <c>+sbwtdcpu none|very_short|short|medium|long|very_long</c></tag> + <item> + <p>As <seealso marker="#+sbwt"><c>+sbwt</c></seealso> but affects + dirty CPU schedulers. Defaults to <c>short</c>.</p> + <note> + <p>This flag can be removed or changed at any time + without prior notice.</p> + </note> + </item> + <tag><marker id="+sbwtdio"/> + <c>+sbwtdio none|very_short|short|medium|long|very_long</c></tag> + <item> + <p>As <seealso marker="#+sbwt"><c>+sbwt</c></seealso> but affects + dirty IO schedulers. Defaults to <c>short</c>.</p> + <note> + <p>This flag can be removed or changed at any time + without prior notice.</p> + </note> + </item> <tag><marker id="+scl"/><c>+scl true|false</c></tag> <item> <p>Enables or disables scheduler compaction of load. By default @@ -1297,25 +1323,6 @@ <seealso marker="erlang#system_info_cpu_topology"> <c>erlang:system_info(cpu_topology)</c></seealso>.</p> </item> - <tag><marker id="+secio"/><c>+secio true|false</c></tag> - <item> - <p>Enables or disables eager check I/O scheduling. Defaults - to <c>true</c>. The default was changed from <c>false</c> - as from ERTS 7.0. The behavior before this - flag was introduced corresponds to <c>+secio false</c>.</p> - <p>The flag effects when schedulers will check for I/O - operations possible to execute, and when such I/O operations - will execute. As the parameter name implies, - schedulers are more eager to check for I/O when - <c>true</c> is passed. This, however, also implies that - execution of outstanding I/O operation is not - prioritized to the same extent as when <c>false</c> is - passed.</p> - <p><seealso marker="erlang#system_info_eager_check_io"> - <c>erlang:system_info(eager_check_io)</c></seealso> - returns the value of this parameter used when starting - the virtual machine.</p> - </item> <tag><marker id="+sfwi"/><c>+sfwi Interval</c></tag> <item> <p>Sets scheduler-forced wakeup interval. All run queues are @@ -1435,6 +1442,26 @@ notice.</p> </note> </item> + <tag><marker id="+swtdcpu"/> + <c>+swtdcpu very_low|low|medium|high|very_high</c></tag> + <item> + <p>As <seealso marker="#+swt"><c>+swt</c></seealso> but + affects dirty CPU schedulers. Defaults to <c>medium</c>.</p> + <note> + <p>This flag can be removed or changed at any time + without prior notice.</p> + </note> + </item> + <tag><marker id="+swtdio"/> + <c>+swtdio very_low|low|medium|high|very_high</c></tag> + <item> + <p>As <seealso marker="#+swt"><c>+swt</c></seealso> but affects + dirty IO schedulers. Defaults to <c>medium</c>.</p> + <note> + <p>This flag can be removed or changed at any time + without prior notice.</p> + </note> + </item> </taglist> </item> <tag><marker id="+t"/><c><![CDATA[+t size]]></c></tag> @@ -1525,6 +1552,15 @@ parameter determines. The lingering prevents repeated deletions and insertions in the tables from occurring.</p> </item> + <tag><marker id="+ztma"/><c>+ztma true | false</c></tag> + <item> + <p>Enables or disables support for tuple module apply in + the emulator. This is a transitional flag for running code + that uses parameterized modules and was compiled under OTP 20 + or earlier. For future compatibility, the modules will need + to be recompiled with the +tuple_calls compiler option. + Defaults to false.</p> + </item> </taglist> </item> </taglist> @@ -1657,9 +1693,7 @@ <tag>The <c>.erlang</c> startup file</tag> <item> <p>When Erlang/OTP is started, the system searches for a file named - <c>.erlang</c> in the directory where Erlang/OTP is started. If not - found, the user's home directory is searched for an <c>.erlang</c> - file.</p> + <c>.erlang</c> in the user's home directory.</p> <p>If an <c>.erlang</c> file is found, it is assumed to contain valid Erlang expressions. These expressions are evaluated as if they were input to the shell.</p> @@ -1711,4 +1745,3 @@ code:load_abs("..../user_default"). ]]></code> <seealso marker="tools:make"><c>make(3)</c></seealso></p> </section> </comref> - |