diff options
Diffstat (limited to 'erts/doc/src/erl.xml')
| -rw-r--r-- | erts/doc/src/erl.xml | 454 |
1 files changed, 360 insertions, 94 deletions
diff --git a/erts/doc/src/erl.xml b/erts/doc/src/erl.xml index 70569b1c6c..37387f2c59 100644 --- a/erts/doc/src/erl.xml +++ b/erts/doc/src/erl.xml @@ -1,23 +1,24 @@ -<?xml version="1.0" encoding="latin1" ?> +<?xml version="1.0" encoding="utf-8" ?> <!DOCTYPE comref SYSTEM "comref.dtd"> <comref> <header> <copyright> - <year>1996</year><year>2013</year> + <year>1996</year><year>2016</year> <holder>Ericsson AB. All Rights Reserved.</holder> </copyright> <legalnotice> - The contents of this file are subject to the Erlang Public License, - Version 1.1, (the "License"); you may not use this file except in - compliance with the License. You should have received a copy of the - Erlang Public License along with this software. If not, it can be - retrieved online at http://www.erlang.org/. + Licensed under the Apache License, Version 2.0 (the "License"); + you may not use this file except in compliance with the License. + You may obtain a copy of the License at + + http://www.apache.org/licenses/LICENSE-2.0 - Software distributed under the License is distributed on an "AS IS" - basis, WITHOUT WARRANTY OF ANY KIND, either express or implied. See - the License for the specific language governing rights and limitations - under the License. + Unless required by applicable law or agreed to in writing, software + distributed under the License is distributed on an "AS IS" BASIS, + WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. + See the License for the specific language governing permissions and + limitations under the License. </legalnotice> @@ -137,7 +138,7 @@ see <seealso marker="kernel:app">app(4)</seealso> and <seealso marker="kernel:application">application(3)</seealso>.</p> </item> - <tag><marker id="args_file"><c><![CDATA[-args_file FileName]]></c></marker></tag> + <tag><marker id="args_file"/><c><![CDATA[-args_file FileName]]></c></tag> <item> <p>Command line arguments are read from the file <c><![CDATA[FileName]]></c>. The arguments read from the file replace the @@ -202,7 +203,7 @@ <seealso marker="kernel:app">app(4)</seealso> and <seealso marker="kernel:application">application(3)</seealso>.</p> </item> - <tag><marker id="connect_all"><c><![CDATA[-connect_all false]]></c></marker></tag> + <tag><marker id="connect_all"/><c><![CDATA[-connect_all false]]></c></tag> <item> <p>If this flag is present, <c><![CDATA[global]]></c> will not maintain a fully connected network of distributed Erlang nodes, and then @@ -287,7 +288,7 @@ <p>Makes <c><![CDATA[init]]></c> write some debug information while interpreting the boot script.</p> </item> - <tag><marker id="instr"><c><![CDATA[-instr]]></c>(emulator flag)</marker></tag> + <tag><marker id="instr"/><c><![CDATA[-instr]]></c>(emulator flag)</tag> <item> <p>Selects an instrumented Erlang runtime system (virtual machine) to run, instead of the ordinary one. When running an @@ -337,7 +338,8 @@ <seealso marker="kernel:net_kernel">net_kernel(3)</seealso>. It is also ensured that <c><![CDATA[epmd]]></c> runs on the current host before Erlang is started. See - <seealso marker="epmd">epmd(1)</seealso>.</p> + <seealso marker="epmd">epmd(1)</seealso> and the + <seealso marker="#start_epmd"><c>-start_epmd</c></seealso> option.</p> <p>The name of the node will be <c><![CDATA[Name@Host]]></c>, where <c><![CDATA[Host]]></c> is the fully qualified host name of the current host. For short names, use the <c><![CDATA[-sname]]></c> flag instead.</p> @@ -370,7 +372,7 @@ path, similar to <c><![CDATA[code:add_pathsa/1]]></c>. See <seealso marker="kernel:code">code(3)</seealso>. As an alternative to <c>-pa</c>, if several directories are - to be prepended to the code and the directories have a + to be prepended to the code path and the directories have a common parent directory, that parent directory could be specified in the <c>ERL_LIBS</c> environment variable. See <seealso marker="kernel:code">code(3)</seealso>.</p> @@ -381,6 +383,33 @@ similar to <c><![CDATA[code:add_pathsz/1]]></c>. See <seealso marker="kernel:code">code(3)</seealso>.</p> </item> + <tag><c><![CDATA[-path Dir1 Dir2 ...]]></c></tag> + <item> + <p>Replaces the path specified in the boot script. See + <seealso marker="sasl:script">script(4)</seealso>.</p> + </item> + <tag><c><![CDATA[-proto_dist Proto]]></c></tag> + <item> + <p>Specify a protocol for Erlang distribution.</p> + <taglist> + <tag><c>inet_tcp</c></tag> + <item> + <p>TCP over IPv4 (the default)</p> + </item> + <tag><c>inet_tls</c></tag> + <item> + <p>distribution over TLS/SSL</p> + </item> + <tag><c>inet6_tcp</c></tag> + <item> + <p>TCP over IPv6</p> + </item> + </taglist> + <p>For example, to start up IPv6 distributed nodes:</p> +<pre> +% <input>erl -name [email protected] -proto_dist inet6_tcp</input> +</pre> + </item> <tag><c><![CDATA[-remsh Node]]></c></tag> <item> <p>Starts Erlang with a remote shell connected to <c><![CDATA[Node]]></c>.</p> @@ -435,7 +464,22 @@ flag and those running with the <c><![CDATA[-name]]></c> flag, as node names must be unique in distributed Erlang systems.</p> </item> - <tag><marker id="smp"><c><![CDATA[-smp [enable|auto|disable]]]></c></marker></tag> + <tag><marker id="start_epmd"/><c>-start_epmd true | false</c></tag> + <item> + + <p>Specifies whether Erlang should start + <seealso marker="epmd">epmd</seealso> on startup. By default + this is <c>true</c>, but if you prefer to start epmd + manually, set this to <c>false</c>.</p> + + <p>This only applies if Erlang is started as a distributed node, + i.e. if <c>-name</c> or <c>-sname</c> is specified. Otherwise, + epmd is not started even if <c>-start_epmd true</c> is given.</p> + + <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> starts the Erlang runtime system with SMP support enabled. This may fail if no runtime @@ -461,7 +505,7 @@ <p><c><![CDATA[erl]]></c> invokes the code for the Erlang emulator (virtual machine), which supports the following flags:</p> <taglist> - <tag><marker id="async_thread_stack_size"><c><![CDATA[+a size]]></c></marker></tag> + <tag><marker id="async_thread_stack_size"/><c><![CDATA[+a size]]></c></tag> <item> <p>Suggested stack size, in kilowords, for threads in the async-thread pool. Valid range is 16-8192 kilowords. The @@ -476,7 +520,7 @@ suggestion, and it might even be ignored on some platforms.</p> </item> - <tag><marker id="async_thread_pool_size"><c><![CDATA[+A size]]></c></marker></tag> + <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. If thread support is available, the default is 10.</p> @@ -495,21 +539,35 @@ <c><![CDATA[werl]]></c>, not <c><![CDATA[erl]]></c> (<c><![CDATA[oldshell]]></c>). Note also that <c><![CDATA[Ctrl-Break]]></c> is used instead of <c><![CDATA[Ctrl-C]]></c> on Windows.</p> </item> - <tag><c><![CDATA[+c]]></c></tag> - <item> - <p>Disable compensation for sudden changes of system time.</p> - <p>Normally, <c><![CDATA[erlang:now/0]]></c> will not immediately reflect - sudden changes in the system time, in order to keep timers - (including <c><![CDATA[receive-after]]></c>) working. Instead, the time - maintained by <c><![CDATA[erlang:now/0]]></c> is slowly adjusted towards - the new system time. (Slowly means in one percent adjustments; - if the time is off by one minute, the time will be adjusted - in 100 minutes.)</p> - <p>When the <c><![CDATA[+c]]></c> option is given, this slow adjustment - will not take place. Instead <c><![CDATA[erlang:now/0]]></c> will always - reflect the current system time. Note that timers are based - on <c><![CDATA[erlang:now/0]]></c>. If the system time jumps, timers - then time out at the wrong time.</p> + <tag><marker id="+c"/><c><![CDATA[+c true | false]]></c></tag> + <item> + <p>Enable or disable + <seealso marker="time_correction#Time_Correction">time correction</seealso>:</p> + <taglist> + <tag><c>true</c></tag> + <item><p>Enable time correction. This is the default if + time correction is supported on the specific platform.</p></item> + + <tag><c>false</c></tag> + <item><p>Disable time correction.</p></item> + </taglist> + <p>For backwards compatibility, the boolean value can be omitted. + This is interpreted as <c>+c false</c>. + </p> + </item> + <tag><marker id="+C_"/><c><![CDATA[+C no_time_warp | single_time_warp | multi_time_warp]]></c></tag> + <item> + <p>Set + <seealso marker="time_correction#Time_Warp_Modes">time warp mode</seealso>: + </p> + <taglist> + <tag><c>no_time_warp</c></tag> + <item><p><seealso marker="time_correction#No_Time_Warp_Mode">No Time Warp Mode</seealso> (the default)</p></item> + <tag><c>single_time_warp</c></tag> + <item><p><seealso marker="time_correction#Single_Time_Warp_Mode">Single Time Warp Mode</seealso></p></item> + <tag><c>multi_time_warp</c></tag> + <item><p><seealso marker="time_correction#Multi_Time_Warp_Mode">Multi Time Warp Mode</seealso></p></item> + </taglist> </item> <tag><c><![CDATA[+d]]></c></tag> <item> @@ -522,9 +580,10 @@ core dump and no crash dump if an internal error is detected.</p> <p>Calling <c>erlang:halt/1</c> with a string argument will still - produce a crash dump.</p> + produce a crash dump. On Unix systems, sending an emulator process + a SIGUSR1 signal will also force a crash dump.</p> </item> - <tag><c><![CDATA[+e Number]]></c></tag> + <tag><marker id="+e"/><c><![CDATA[+e Number]]></c></tag> <item> <p>Set max number of ETS tables.</p> </item> @@ -535,12 +594,15 @@ </item> <tag><marker id="file_name_encoding"></marker><c><![CDATA[+fnl]]></c></tag> <item> - <p>The VM works with file names as if they are encoded using the ISO-latin-1 encoding, disallowing Unicode characters with codepoints beyond 255. This is default on operating systems that have transparent file naming, i.e. all Unixes except MacOSX.</p> - <p>See <seealso marker="stdlib:unicode_usage#unicode_file_names">STDLIB User's Guide</seealso> for more infomation about unicode file names.</p> + <p>The VM works with file names as if they are encoded using the ISO-latin-1 encoding, disallowing Unicode characters with codepoints beyond 255.</p> + <p>See <seealso marker="stdlib:unicode_usage#unicode_file_names">STDLIB User's Guide</seealso> for more infomation about unicode file names. Note that this value also applies to command-line parameters and environment variables (see <seealso marker="stdlib:unicode_usage#unicode_in_environment_and_parameters">STDLIB User's Guide</seealso>).</p> </item> <tag><c><![CDATA[+fnu[{w|i|e}]]]></c></tag> <item> - <p>The VM works with file names as if they are encoded using UTF-8 (or some other system specific Unicode encoding). This is the default on operating systems that enforce Unicode encoding, i.e. Windows and MacOSX.</p> + <p>The VM works with file names as if they are encoded using + UTF-8 (or some other system specific Unicode encoding). This + is the default on operating systems that enforce Unicode + encoding, i.e. Windows and MacOS X.</p> <p>The <c>+fnu</c> switch can be followed by <c>w</c>, <c>i</c>, or <c>e</c> to control the way wrongly encoded file names are to be reported. <c>w</c> means that a warning is @@ -552,11 +614,16 @@ encountered. <c>w</c> is the default. Note that <c>file:read_link/1</c> will always return an error if the link points to an invalid file name.</p> - <p>See <seealso marker="stdlib:unicode_usage#unicode_file_names">STDLIB User's Guide</seealso> for more infomation about unicode file names.</p> + <p>See <seealso marker="stdlib:unicode_usage#unicode_file_names">STDLIB User's Guide</seealso> for more infomation about unicode file names. Note that this value also applies to command-line parameters and environment variables (see <seealso marker="stdlib:unicode_usage#unicode_in_environment_and_parameters">STDLIB User's Guide</seealso>).</p> </item> <tag><c><![CDATA[+fna[{w|i|e}]]]></c></tag> <item> - <p>Selection between <c>+fnl</c> and <c>+fnu</c> is done based on the current locale settings in the OS, meaning that if you have set your terminal for UTF-8 encoding, the filesystem is expected to use the same encoding for file names (use with care).</p> + <p>Selection between <c>+fnl</c> and <c>+fnu</c> is done based + on the current locale settings in the OS, meaning that if you + have set your terminal for UTF-8 encoding, the filesystem is + expected to use the same encoding for file names. This is + default on all operating systems except MacOS X and + Windows.</p> <p>The <c>+fna</c> switch can be followed by <c>w</c>, <c>i</c>, or <c>e</c>. This will have effect if the locale settings cause the behavior of <c>+fnu</c> to be selected. @@ -564,7 +631,7 @@ settings cause the behavior of <c>+fnl</c> to be selected, then <c>w</c>, <c>i</c>, or <c>e</c> will not have any effect.</p> - <p>See <seealso marker="stdlib:unicode_usage#unicode_file_names">STDLIB User's Guide</seealso> for more infomation about unicode file names.</p> + <p>See <seealso marker="stdlib:unicode_usage#unicode_file_names">STDLIB User's Guide</seealso> for more infomation about unicode file names. Note that this value also applies to command-line parameters and environment variables (see <seealso marker="stdlib:unicode_usage#unicode_in_environment_and_parameters">STDLIB User's Guide</seealso>).</p> </item> <tag><c><![CDATA[+hms Size]]></c></tag> <item> @@ -576,6 +643,45 @@ <p>Sets the default binary virtual heap size of processes to the size <c><![CDATA[Size]]></c>.</p> </item> + <tag><marker id="+hmax"/><c><![CDATA[+hmax Size]]></c></tag> + <item> + <p>Sets the default maximum heap size of processes to the size + <c><![CDATA[Size]]></c>. If <c>+hmax</c> is not given, the default is <c>0</c> + which means that no maximum heap size is used. + For more information, see the documentation of + <seealso marker="erlang#process_flag_max_heap_size"> + <c>process_flag(max_heap_size, MaxHeapSize)</c></seealso>.</p> + </item> + <tag><marker id="+hmaxel"/><c><![CDATA[+hmaxel true|false]]></c></tag> + <item> + <p>Sets whether to send an error logger message for processes that reach + the maximum heap size or not. If <c>+hmaxel</c> is not given, the default is <c>true</c>. + For more information, see the documentation of + <seealso marker="erlang#process_flag_max_heap_size"> + <c>process_flag(max_heap_size, MaxHeapSize)</c></seealso>.</p> + </item> + <tag><marker id="+hmaxk"/><c><![CDATA[+hmaxk true|false]]></c></tag> + <item> + <p>Sets whether to kill processes that reach the maximum heap size or not. If + <c>+hmaxk</c> is not given, the default is <c>true</c>. For more information, + see the documentation of + <seealso marker="erlang#process_flag_max_heap_size"> + <c>process_flag(max_heap_size, MaxHeapSize)</c></seealso>.</p> + </item> + <tag><c><![CDATA[+hpds Size]]></c></tag> + <item> + <p>Sets the initial process dictionary size of processes to the size + <c><![CDATA[Size]]></c>.</p> + </item> + <tag><marker id="+hmqd"/><c>+hmqd off_heap|on_heap</c></tag> + <item><p> + Sets the default value for the process flag + <c>message_queue_data</c>. If <c>+hmqd</c> is not + passed, <c>on_heap</c> will be the default. For more information, + see the documentation of + <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> <item> <p>Enables or disables the kernel poll functionality if @@ -596,7 +702,7 @@ information about the file names and line numbers. </p> </item> - <tag><marker id="erts_alloc"><c><![CDATA[+MFlag Value]]></c></marker></tag> + <tag><marker id="erts_alloc"/><c><![CDATA[+MFlag Value]]></c></tag> <item> <p>Memory allocator specific flags, see <seealso marker="erts_alloc">erts_alloc(3)</seealso> for @@ -635,10 +741,10 @@ debugging.</item> </taglist> </item> - <tag><marker id="+pc"/><marker id="printable_character_range"><c><![CDATA[+pc Range]]></c></marker></tag> + <tag><marker id="+pc"/><marker id="printable_character_range"/><c><![CDATA[+pc Range]]></c></tag> <item> <p>Sets the range of characters that the system will consider printable in heuristic detection of strings. This typically affects the shell, debugger and io:format functions (when ~tp is used in the format string).</p> - <p>Currently two values for the <c>Range</c> are supported: + <p>Currently two values for the <c>Range</c> are supported:</p> <taglist> <tag><c>latin1</c></tag> <item>The default. Only characters in the ISO-latin-1 range can be considered printable, which means @@ -653,11 +759,10 @@ example your font does not cover all Unicode characters.</item> </taglist> - </p> <p>Se also <seealso marker="stdlib:io#printable_range/0"> io:printable_range/0</seealso>.</p> </item> - <tag><marker id="+P"/><marker id="max_processes"><c><![CDATA[+P Number|legacy]]></c></marker></tag> + <tag><marker id="+P"/><marker id="max_processes"/><c><![CDATA[+P Number|legacy]]></c></tag> <item> <p>Sets the maximum number of simultaneously existing processes for this system if a <c>Number</c> is passed as value. Valid range for @@ -677,7 +782,7 @@ circumstances be extremely expensive. The legacy algoritm is deprecated, and the <c>legacy</c> option is scheduled for removal in OTP-R18.</p> </item> - <tag><marker id="+Q"/><marker id="max_ports"><c><![CDATA[+Q Number|legacy]]></c></marker></tag> + <tag><marker id="+Q"/><marker id="max_ports"/><c><![CDATA[+Q Number|legacy]]></c></tag> <item> <p>Sets the maximum number of simultaneously existing ports for this system if a Number is passed as value. Valid range for <c>Number</c> @@ -708,7 +813,7 @@ circumstances be extremely expensive. The legacy algoritm is deprecated, and the <c>legacy</c> option is scheduled for removal in OTP-R18.</p> </item> - <tag><marker id="compat_rel"><c><![CDATA[+R ReleaseNumber]]></c></marker></tag> + <tag><marker id="compat_rel"/><c><![CDATA[+R ReleaseNumber]]></c></tag> <item> <p>Sets the compatibility mode.</p> <p>The distribution mechanism is not backwards compatible by @@ -728,7 +833,7 @@ <item> <p>Force ets memory block to be moved on realloc.</p> </item> - <tag><marker id="+rg"><c><![CDATA[+rg ReaderGroupsLimit]]></c></marker></tag> + <tag><marker id="+rg"/><c><![CDATA[+rg ReaderGroupsLimit]]></c></tag> <item> <p>Limits the amount of reader groups used by read/write locks optimized for read operations in the Erlang runtime system. By @@ -746,29 +851,133 @@ 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 - threads to set online when SMP support has been enabled. - Valid range for both values are 1-1024. If the - Erlang runtime system is able to determine the amount - of logical processors configured and logical processors available, - <c>Schedulers</c> will default to logical processors configured, - and <c>SchedulersOnline</c> will default to logical processors - available; otherwise, the default values will be 1. <c>Schedulers</c> - may be omitted if <c>:SchedulerOnline</c> is not and vice versa. The - amount of schedulers online can be changed at run time via + <tag><marker id="+S"/><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 values is 1024. If the Erlang runtime system is able to determine the + amount of logical processors configured and logical processors available, + <c>Schedulers</c> will default to logical processors configured, and + <c>SchedulersOnline</c> will default to logical processors available; + otherwise, the default values will be 1. <c>Schedulers</c> may be omitted + if <c>:SchedulerOnline</c> is not and vice versa. The number of schedulers + online can be changed at run time via <seealso marker="erlang#system_flag_schedulers_online">erlang:system_flag(schedulers_online, SchedulersOnline)</seealso>. </p> - <p>This flag will be ignored if the emulator doesn't have + <p>If <c>Schedulers</c> or <c>SchedulersOnline</c> is specified as a + negative number, the value is subtracted from the default number of + logical processors configured or logical processors available, respectively. + </p> + <p>Specifying the value 0 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 doesn't have SMP support enabled (see the <seealso marker="#smp">-smp</seealso> flag).</p> </item> + <tag><marker id="+SP"/><c><![CDATA[+SP SchedulersPercentage:SchedulersOnlinePercentage]]></c></tag> + <item> + <p>Similar to <seealso marker="#+S">+S</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 greater than 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. + <c>SchedulersPercentage</c> may be omitted if <c>:SchedulersOnlinePercentage</c> is + not and vice versa. The number of schedulers online can be changed at run time via + <seealso marker="erlang#system_flag_schedulers_online">erlang:system_flag(schedulers_online, SchedulersOnline)</seealso>. + </p> + <p>This option interacts with <seealso marker="#+S">+S</seealso> settings. + For example, on a system with 8 logical cores configured 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 doesn't have + SMP support enabled (see the <seealso marker="#smp">-smp</seealso> + flag).</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 further + limited by the settings for normal schedulers: the number of dirty CPU + scheduler threads created cannot exceed the number of normal scheduler + threads created, and the number of dirty CPU scheduler threads online + cannot exceed the number of normal scheduler threads online (see the + <seealso marker="#+S">+S</seealso> and <seealso marker="#+SP">+SP</seealso> + flags for more details). By default, the number of dirty CPU scheduler + threads created equals the number of normal scheduler threads created, + and the number of dirty CPU scheduler threads online equals the number + of normal scheduler threads online. <c>DirtyCPUSchedulers</c> may be + omitted if <c>:DirtyCPUSchedulersOnline</c> is not and vice versa. The + number of dirty CPU schedulers online can be changed at run time via + <seealso marker="erlang#system_flag_dirty_cpu_schedulers_online">erlang:system_flag(dirty_cpu_schedulers_online, DirtyCPUSchedulersOnline)</seealso>. + </p> + <p> + The amount of dirty CPU schedulers is limited by the amount of + normal schedulers in order to limit the effect on processes + 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 doesn't have threading support + enabled. Currently, <em>this option is experimental</em> and is supported only + if the emulator was configured and built with support for dirty schedulers + enabled (it's disabled by default). + </p> + </item> + <tag><marker id="+SDPcpu"/><c><![CDATA[+SDPcpu DirtyCPUSchedulersPercentage:DirtyCPUSchedulersOnlinePercentage]]></c></tag> + <item> + <p>Similar to <seealso marker="#+SDcpu">+SDcpu</seealso> but uses percentages to set the + number of dirty CPU scheduler threads to create and number of dirty CPU scheduler threads + to set online when threading support has been enabled. Specified values must be greater + than 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 logical processors available. <c>DirtyCPUSchedulersPercentage</c> may + be omitted if <c>:DirtyCPUSchedulersOnlinePercentage</c> is not and vice versa. The + number of dirty CPU schedulers online can be changed at run time via + <seealso marker="erlang#system_flag_dirty_cpu_schedulers_online">erlang:system_flag(dirty_cpu_schedulers_online, DirtyCPUSchedulersOnline)</seealso>. + </p> + <p>This option interacts with <seealso marker="#+SDcpu">+SDcpu</seealso> settings. + For example, on a system with 8 logical cores configured and 8 logical cores available, + 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 doesn't have threading support + enabled. Currently, <em>this option is experimental</em> and is supported only + if the emulator was configured and built with support for dirty schedulers + enabled (it's disabled by default). + </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. The 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> + <p> + The amount of dirty IO schedulers is not limited by the amount of + normal schedulers <seealso marker="#+SDcpu">like the amount of + dirty CPU schedulers</seealso>. This since only I/O bound work is + 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 doesn't have threading support + enabled. Currently, <em>this option is experimental</em> and is supported only + if the emulator was configured and built with support for dirty schedulers + enabled (it's disabled by default). + </p> + </item> <tag><c><![CDATA[+sFlag Value]]></c></tag> <item> <p>Scheduling specific flags.</p> <taglist> - <tag><marker id="+sbt"><c>+sbt BindType</c></marker></tag> + <tag><marker id="+sbt"/><c>+sbt BindType</c></tag> <item> <p>Set scheduler bind type.</p> <p>Schedulers can also be bound using the @@ -892,7 +1101,7 @@ <seealso marker="erlang#system_info_scheduler_bindings">erlang:system_info(scheduler_bindings)</seealso>. </p> </item> - <tag><marker id="+sbwt"><c>+sbwt none|very_short|short|medium|long|very_long</c></marker></tag> + <tag><marker id="+sbwt"/><c>+sbwt none|very_short|short|medium|long|very_long</c></tag> <item> <p>Set scheduler busy wait threshold. Default is <c>medium</c>. The threshold determines how long schedulers should busy @@ -902,7 +1111,7 @@ without prior notice. </p> </item> - <tag><marker id="+scl"><c>+scl true|false</c></marker></tag> + <tag><marker id="+scl"/><c>+scl true|false</c></tag> <item> <p>Enable or disable scheduler compaction of load. By default scheduler compaction of load is enabled. When enabled, load @@ -913,9 +1122,13 @@ when schedulers frequently run out of work. When disabled, the frequency with which schedulers run out of work will not be taken into account by the load balancing logic. + <br/> <c>+scl false</c> is similar to + <seealso marker="#+sub">+sub true</seealso> with the difference + that <c>+sub true</c> also will balance scheduler utilization + between schedulers. </p> </item> - <tag><marker id="+sct"><c>+sct CpuTopology</c></marker></tag> + <tag><marker id="+sct"/><c>+sct CpuTopology</c></tag> <item> <list type="bulleted"> <item><c><![CDATA[<Id> = integer(); when 0 =< <Id> =< 65535]]></c></item> @@ -1037,7 +1250,24 @@ <p>For more information, see <seealso marker="erlang#system_info_cpu_topology">erlang:system_info(cpu_topology)</seealso>.</p> </item> - <tag><marker id="+sfwi"><c>+sfwi Interval</c></marker></tag> + <tag><marker id="+secio"/><c>+secio true|false</c></tag> + <item> + <p>Enable or disable eager check I/O scheduling. The default + is currently <c>true</c>. The default was changed from <c>false</c> + to <c>true</c> as of erts version 7.0. The behaviour 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 name of the parameter implies, + schedulers will be more eager to check for I/O when + <c>true</c> is passed. This however also implies that + execution of outstanding I/O operation will not be + 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 VM.</p> + </item> + <tag><marker id="+sfwi"/><c>+sfwi Interval</c></tag> <item> <p>Set scheduler forced wakeup interval. All run queues will be scanned each <c>Interval</c> milliseconds. While there are @@ -1046,12 +1276,12 @@ disables this feature, which also is the default. </p> <p>This feature has been introduced as a temporary workaround - for lengthy executing native code, and native code that do not + for long-executing native code, and native code that does not bump reductions properly in OTP. When these bugs have be fixed the <c>+sfwi</c> flag will be removed. </p> </item> - <tag><marker id="+stbt"><c>+stbt BindType</c></marker></tag> + <tag><marker id="+stbt"/><c>+stbt BindType</c></tag> <item> <p>Try to set scheduler bind type. The same as the <seealso marker="#+sbt">+sbt</seealso> flag with the exception of @@ -1059,7 +1289,30 @@ documentation of the <seealso marker="#+sbt">+sbt</seealso> flag. </p> </item> - <tag><marker id="+swct"><c>+sws very_eager|eager|medium|lazy|very_lazy</c></marker></tag> + <tag><marker id="+sub"/><c>+sub true|false</c></tag> + <item> + <p>Enable or disable + <seealso marker="erts:erlang#statistics_scheduler_wall_time">scheduler + utilization</seealso> balancing of load. By default scheduler + utilization balancing is disabled and instead scheduler + compaction of load is enabled which will strive for a load + distribution which causes as many scheduler threads as possible + to be fully loaded (i.e., not run out of work). When scheduler + utilization balancing is enabled the system will instead try to + balance scheduler utilization between schedulers. That is, + strive for equal scheduler utilization on all schedulers. + <br/> <c>+sub true</c> is only supported on + systems where the runtime system detects and uses a monotonically + increasing high resolution clock. On other systems, the runtime + system will fail to start. + <br/> <c>+sub true</c> implies + <seealso marker="#+scl">+scl false</seealso>. The difference + between <c>+sub true</c> and <c>+scl false</c> is that + <c>+scl false</c> will not try to balance the scheduler + utilization. + </p> + </item> + <tag><marker id="+swct"/><c>+swct very_eager|eager|medium|lazy|very_lazy</c></tag> <item> <p> Set scheduler wake cleanup threshold. Default is <c>medium</c>. @@ -1073,7 +1326,7 @@ <p><em>NOTE:</em> This flag may be removed or changed at any time without prior notice. </p> </item> - <tag><marker id="+sws"><c>+sws default|legacy</c></marker></tag> + <tag><marker id="+sws"/><c>+sws default|legacy</c></tag> <item> <p> Set scheduler wakeup strategy. Default strategy changed in erts-5.10/OTP-R16A. This strategy was previously known as <c>proposal</c> in OTP-R15. The <c>legacy</c> strategy was used as default from R13 up to and including R15. @@ -1081,7 +1334,7 @@ <p><em>NOTE:</em> This flag may be removed or changed at any time without prior notice. </p> </item> - <tag><marker id="+swt"><c>+swt very_low|low|medium|high|very_high</c></marker></tag> + <tag><marker id="+swt"/><c>+swt very_low|low|medium|high|very_high</c></tag> <item> <p>Set scheduler wakeup threshold. Default is <c>medium</c>. The threshold determines when to wake up sleeping schedulers @@ -1095,23 +1348,23 @@ without prior notice. </p> </item> - <tag><marker id="+spp"><c>+spp Bool</c></marker></tag> + <tag><marker id="+spp"/><c>+spp Bool</c></tag> <item> <p>Set default scheduler hint for port parallelism. If set to - <c>true</c>, the VM will schedule port tasks when it by this can - improve the parallelism in the system. If set to <c>false</c>, - the VM will try to perform port tasks immediately and by this - improve latency at the expense of parallelism. If this - flag has not been passed, the default scheduler hint for port - parallelism is currently <c>false</c>. The default used can be - inspected in runtime by calling - <seealso marker="erlang#system_info_port_parallelism">erlang:system_info(port_parallelism)</seealso>. + <c>true</c>, the VM will schedule port tasks when doing so will + improve parallelism in the system. If set to <c>false</c>, the VM + will try to perform port tasks immediately, improving latency at the + expense of parallelism. If this flag has not been passed, the + default scheduler hint for port parallelism is currently + <c>false</c>. The default used can be inspected in runtime by + calling <seealso + marker="erlang#system_info_port_parallelism">erlang:system_info(port_parallelism)</seealso>. The default can be overriden on port creation by passing the <seealso marker="erlang#open_port_parallelism">parallelism</seealso> - option to - <seealso marker="erlang#open_port/2">open_port/2</seealso></p>. + option to <seealso + marker="erlang#open_port/2">open_port/2</seealso></p>. </item> - <tag><marker id="sched_thread_stack_size"><c><![CDATA[+sss size]]></c></marker></tag> + <tag><marker id="sched_thread_stack_size"/><c><![CDATA[+sss size]]></c></tag> <item> <p>Suggested stack size, in kilowords, for scheduler threads. Valid range is 4-8192 kilowords. The default stack size @@ -1119,11 +1372,11 @@ </item> </taglist> </item> - <tag><marker id="+t"><c><![CDATA[+t size]]></c></marker></tag> + <tag><marker id="+t"/><c><![CDATA[+t size]]></c></tag> <item> <p>Set the maximum number of atoms the VM can handle. Default is 1048576.</p> </item> - <tag><marker id="+T"><c><![CDATA[+T Level]]></c></marker></tag> + <tag><marker id="+T"/><c><![CDATA[+T Level]]></c></tag> <item> <p>Enables modified timing and sets the modified timing level. Currently valid range is 0-9. The timing of the runtime system @@ -1161,13 +1414,14 @@ <item> <p>Verbose.</p> </item> - <tag><c><![CDATA[+W w | i]]></c></tag> + <tag><c><![CDATA[+W w | i | e]]></c></tag> <item> <p>Sets the mapping of warning messages for <c><![CDATA[error_logger]]></c>. Messages sent to the error logger using one of the warning - routines can be mapped either to errors (default), warnings - (<c><![CDATA[+W w]]></c>), or info reports (<c><![CDATA[+W i]]></c>). The current - mapping can be retrieved using + routines can be mapped either to errors (<c><![CDATA[+W e]]></c>), + warnings (<c><![CDATA[+W w]]></c>), or info reports + (<c><![CDATA[+W i]]></c>). The default is warnings. + The current mapping can be retrieved using <c><![CDATA[error_logger:warning_map/0]]></c>. See <seealso marker="kernel:error_logger#warning_map/0">error_logger(3)</seealso> for further information.</p> @@ -1176,7 +1430,7 @@ <item> <p>Miscellaneous flags.</p> <taglist> - <tag><marker id="+zdbbl"><c>+zdbbl size</c></marker></tag> + <tag><marker id="+zdbbl"/><c>+zdbbl size</c></tag> <item> <p>Set the distribution buffer busy limit (<seealso marker="erlang#system_info_dist_buf_busy_limit">dist_buf_busy_limit</seealso>) @@ -1189,6 +1443,18 @@ give lower latency and higher throughput at the expense of higher memory usage.</p> </item> + <tag><marker id="+zdntgc"/><c>+zdntgc time</c></tag> + <item> + <p>Set the delayed node table garbage collection time + (<seealso marker="erlang#system_info_delayed_node_table_gc">delayed_node_table_gc</seealso>) + in seconds. Valid values are either <c>infinity</c> or + an integer in the range [0-100000000]. Default is 60.</p> + <p>Node table entries that are not referred will linger + in the table for at least the amount of time that this + parameter determines. The lingering prevents repeated + deletions and insertions in the tables from occurring. + </p> + </item> </taglist> </item> </taglist> @@ -1251,7 +1517,7 @@ </item> </taglist> </item> - <tag><marker id="ERL_AFLAGS"><c><![CDATA[ERL_AFLAGS]]></c></marker></tag> + <tag><marker id="ERL_AFLAGS"/><c><![CDATA[ERL_AFLAGS]]></c></tag> <item> <p>The content of this environment variable will be added to the beginning of the command line for <c><![CDATA[erl]]></c>.</p> @@ -1261,7 +1527,7 @@ the <c><![CDATA[-extra]]></c> section, i.e. the end of the command line following after an <c><![CDATA[-extra]]></c> flag.</p> </item> - <tag><marker id="ERL_ZFLAGS"><c><![CDATA[ERL_ZFLAGS]]></c></marker> and <marker id="ERL_FLAGS"><c><![CDATA[ERL_FLAGS]]></c></marker></tag> + <tag><marker id="ERL_ZFLAGS"/><c><![CDATA[ERL_ZFLAGS]]></c> and <marker id="ERL_FLAGS"/><c><![CDATA[ERL_FLAGS]]></c></tag> <item> <p>The content of these environment variables will be added to the end of the command line for <c><![CDATA[erl]]></c>.</p> |