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Diffstat (limited to 'erts/doc/src/erl.xml')
| -rw-r--r-- | erts/doc/src/erl.xml | 416 |
1 files changed, 361 insertions, 55 deletions
diff --git a/erts/doc/src/erl.xml b/erts/doc/src/erl.xml index f931445a3e..f856b9ab86 100644 --- a/erts/doc/src/erl.xml +++ b/erts/doc/src/erl.xml @@ -1,10 +1,10 @@ -<?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>2012</year> + <year>1996</year><year>2013</year> <holder>Ericsson AB. All Rights Reserved.</holder> </copyright> <legalnotice> @@ -479,7 +479,7 @@ <tag><marker id="async_thread_pool_size"><c><![CDATA[+A size]]></c></marker></tag> <item> <p>Sets the number of threads in async thread pool, valid range - is 0-1024. Default is 0.</p> + is 0-1024. If thread support is available, the default is 10.</p> </item> <tag><c><![CDATA[+B [c | d | i]]]></c></tag> <item> @@ -495,7 +495,7 @@ <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> + <tag><marker id="+c"><c><![CDATA[+c]]></c></marker></tag> <item> <p>Disable compensation for sudden changes of system time.</p> <p>Normally, <c><![CDATA[erlang:now/0]]></c> will not immediately reflect @@ -510,6 +510,9 @@ 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> + <p><em>NOTE</em>: You can check whether the adjustment is enabled or + disabled by calling + <seealso marker="erlang#system_info_tolerant_timeofday">erlang:system_info(tolerant_timeofday)</seealso>.</p> </item> <tag><c><![CDATA[+d]]></c></tag> <item> @@ -524,7 +527,7 @@ <p>Calling <c>erlang:halt/1</c> with a string argument will still produce a crash dump.</p> </item> - <tag><c><![CDATA[+e Number]]></c></tag> + <tag><marker id="+e"><c><![CDATA[+e Number]]></c></marker></tag> <item> <p>Set max number of ETS tables.</p> </item> @@ -535,16 +538,44 @@ </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> - </item> - <tag><c><![CDATA[+fnu]]></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>By enabling Unicode file name translation on systems where this is not default, you open up to the possibility that some file names can not be interpreted by the VM and therefore will be returned to the program as raw binaries. The option is therefore considered experimental.</p> - </item> - <tag><c><![CDATA[+fna]]></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 filenames (use with care).</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 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 + sent to the <c>error_logger</c> whenever a wrongly encoded + file name is "skipped" in directory listings, <c>i</c> means + that those wrongly encoded file names are silently ignored and + <c>e</c> means that the API function will return an error + whenever a wrongly encoded file (or directory) name is + 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. 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. 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. + See the description of <c>+fnu</c> above. If the locale + 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. 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> @@ -571,9 +602,9 @@ </item> <tag><c><![CDATA[+L]]></c></tag> <item> - <p>Don't load information about source filenames and line numbers. + <p>Don't load information about source file names and line numbers. This will save some memory, but exceptions will not contain - information about the filenames and line numbers. + information about the file names and line numbers. </p> </item> <tag><marker id="erts_alloc"><c><![CDATA[+MFlag Value]]></c></marker></tag> @@ -582,11 +613,111 @@ <seealso marker="erts_alloc">erts_alloc(3)</seealso> for further information.</p> </item> - <tag><marker id="max_processes"><c><![CDATA[+P Number]]></c></marker></tag> - <item> - <p>Sets the maximum number of concurrent processes for this - system. <c><![CDATA[Number]]></c> must be in the range 16..134217727. - Default is 32768.</p> + <tag><marker id="+n"/><c><![CDATA[+n Behavior]]></c></tag> + <item> + <p>Control behavior of signals to ports.</p> + <p>As of OTP-R16 signals to ports are truly asynchronously + delivered. Note that signals always have been documented as + asynchronous. The underlying implementation has, however, + previously delivered these signals synchronously. Correctly + written Erlang programs should be able to handle this without + any issues. Bugs in existing Erlang programs that make false + assumptions about signals to ports may, however, be tricky to + find. This switch has been introduced in order to at least + make it easier to compare behaviors during a transition period. + Note that <em>this flag is deprecated</em> as of its + introduction, and is scheduled for removal in OTP-R17. + <c>Behavior</c> should be one of the following characters:</p> + <taglist> + <tag><c>d</c></tag> + <item>The default. Asynchronous signals. A process that sends + a signal to a port may continue execution before the signal + has been delivered to the port.</item> + <tag><c>s</c></tag> + <item>Synchronous signals. A processes that sends a signal + to a port will not continue execution until the signal has + been delivered. Should <em>only</em> be used for testing and + debugging.</item> + <tag><c>a</c></tag> + <item>Asynchronous signals. As the default, but a processes + that sends a signal will even more frequently continue + execution before the signal has been delivered to the + port. Should <em>only</em> be used for testing and + debugging.</item> + </taglist> + </item> + <tag><marker id="+pc"/><marker id="printable_character_range"><c><![CDATA[+pc Range]]></c></marker></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: + <taglist> + <tag><c>latin1</c></tag> <item>The default. Only characters + in the ISO-latin-1 range can be considered printable, which means + that a character with a code point > 255 will never be + considered printable and that lists containing such + characters will be displayed as lists of integers rather + than text strings by tools.</item> + <tag><c>unicode</c></tag> + <item>All printable Unicode characters are considered when + determining if a list of integers is to be displayed in + string syntax. This may give unexpected results if for + 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> + <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 + <c>Number</c> is <c>[1024-134217727]</c></p> + <p><em>NOTE</em>: The actual maximum chosen may be much larger than + the <c>Number</c> passed. Currently the runtime system often, + but not always, chooses a value that is a power of 2. This might, + however, be changed in the future. The actual value chosen can be + checked by calling + <seealso marker="erlang#system_info_process_limit">erlang:system_info(process_limit)</seealso>.</p> + <p>The default value is <c>262144</c></p> + <p>If <c>legacy</c> is passed as value, the legacy algorithm for + allocation of process identifiers will be used. Using the legacy + algorithm, identifiers will be allocated in a strictly increasing + fashion until largest possible identifier has been reached. Note that + this algorithm suffers from performance issues and can under certain + 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> + <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> + is <c>[1024-134217727]</c></p> + <p><em>NOTE</em>: The actual maximum chosen may be much larger than + the actual <c>Number</c> passed. Currently the runtime system often, + but not always, chooses a value that is a power of 2. This might, + however, be changed in the future. The actual value chosen can be + checked by calling + <seealso marker="erlang#system_info_port_limit">erlang:system_info(port_limit)</seealso>.</p> + <p>The default value used is normally <c>65536</c>. However, if + the runtime system is able to determine maximum amount of file + descriptors that it is allowed to open and this value is larger + than <c>65536</c>, the chosen value will increased to a value + larger or equal to the maximum amount of file descriptors that + can be opened.</p> + <p>On Windows the default value is set to <c>8196</c> because the + normal OS limitations are set higher than most machines can handle.</p> + <p>Previously the environment variable <c>ERL_MAX_PORTS</c> was used + for setting the maximum number of simultaneously existing ports. This + environment variable is deprecated, and scheduled for removal in + OTP-R17, but can still be used.</p> + <p>If <c>legacy</c> is passed as value, the legacy algorithm for + allocation of port identifiers will be used. Using the legacy + algorithm, identifiers will be allocated in a strictly increasing + fashion until largest possible identifier has been reached. Note that + this algorithm suffers from performance issues and can under certain + 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> <item> @@ -595,21 +726,14 @@ default. This flags sets the emulator in compatibility mode with an earlier Erlang/OTP release <c><![CDATA[ReleaseNumber]]></c>. The release number must be in the range - <c><![CDATA[7..<current release>]]></c>. This limits the emulator, - making it possible for it to communicate with Erlang nodes - (as well as C- and Java nodes) running that earlier release.</p> - <p>For example, an R10 node is not automatically compatible - with an R9 node, but R10 nodes started with the <c><![CDATA[+R 9]]></c> - flag can co-exist with R9 nodes in the same distributed - Erlang system, they are R9-compatible.</p> + <c><![CDATA[<current release>-2..<current release>]]></c>. This + limits the emulator, making it possible for it to communicate + with Erlang nodes (as well as C- and Java nodes) running that + earlier release.</p> <p>Note: Make sure all nodes (Erlang-, C-, and Java nodes) of a distributed Erlang system is of the same Erlang/OTP release, or from two different Erlang/OTP releases X and Y, where <em>all</em> Y nodes have compatibility mode X.</p> - <p>For example: A distributed Erlang system can consist of - R10 nodes, or of R9 nodes and R9-compatible R10 nodes, but - not of R9 nodes, R9-compatible R10 nodes and "regular" R10 - nodes, as R9 and "regular" R10 nodes are not compatible.</p> </item> <tag><c><![CDATA[+r]]></c></tag> <item> @@ -619,7 +743,7 @@ <item> <p>Limits the amount of reader groups used by read/write locks optimized for read operations in the Erlang runtime system. By - default the reader groups limit equals 8.</p> + default the reader groups limit equals 64.</p> <p>When the amount of schedulers is less than or equal to the reader groups limit, each scheduler has its own reader group. When the amount of schedulers is larger than the reader groups limit, @@ -635,29 +759,135 @@ </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 + <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>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></marker></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 flag will be ignored if the emulator doesn't have + <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></marker></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>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></marker></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 IOSchedulers]]></c></marker></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>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> <item> - <p>Set scheduler bind type. Currently valid <c>BindType</c>s: + <p>Set scheduler bind type.</p> + <p>Schedulers can also be bound using the + <seealso marker="#+stbt">+stbt</seealso> flag. The only difference + between these two flags is how the following errors are handled:</p> + <list> + <item>Binding of schedulers is not supported on the specific + platform.</item> + <item>No available CPU topology. That is the runtime system + was not able to automatically detected the CPU topology, and + no <seealso marker="#+sct">user defined CPU topology</seealso> + was set.</item> + </list> + <p>If any of these errors occur when <c>+sbt</c> has been passed, + the runtime system will print an error message, and refuse to + start. If any of these errors occur when <c>+stbt</c> has been + passed, the runtime system will silently ignore the error, and + start up using unbound schedulers.</p> + <p>Currently valid <c>BindType</c>s: </p> <taglist> <tag><c>u</c></tag> @@ -783,6 +1013,10 @@ 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> @@ -907,15 +1141,71 @@ <p>For more information, see <seealso marker="erlang#system_info_cpu_topology">erlang:system_info(cpu_topology)</seealso>.</p> </item> - <tag><marker id="+sws"><c>+sws default|legacy|proposal</c></marker></tag> + <tag><marker id="+sfwi"><c>+sfwi Interval</c></marker></tag> + <item> + <p>Set scheduler forced wakeup interval. All run queues will + be scanned each <c>Interval</c> milliseconds. While there are + sleeping schedulers in the system, one scheduler will be woken + for each non-empty run queue found. An <c>Interval</c> of zero + 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 + 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> + <item> + <p>Try to set scheduler bind type. The same as the + <seealso marker="#+sbt">+sbt</seealso> flag with the exception of + how some errors are handled. For more information, see the + documentation of the <seealso marker="#+sbt">+sbt</seealso> flag. + </p> + </item> + <tag><marker id="+sub"><c>+sub true|false</c></marker></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 use 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></marker></tag> <item> - <p>Set scheduler wakeup strategy. Default is <c>legacy</c> (has been - used since OTP-R13B). The <c>proposal</c> strategy is the currently - proposed strategy for OTP-R16. Note that the <c>proposal</c> strategy - might change during OTP-R15. + <p> + Set scheduler wake cleanup threshold. Default is <c>medium</c>. + This flag controls how eager schedulers should be requesting + wake up due to certain cleanup operations. When a lazy setting + is used, more outstanding cleanup operations can be left undone + while a scheduler is idling. When an eager setting is used, + schedulers will more frequently be woken, potentially increasing + CPU-utilization. </p> - <p><em>NOTE:</em> This flag may be removed or changed at any time - without prior notice. + <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> + <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. + </p> + <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> @@ -932,6 +1222,22 @@ without prior notice. </p> </item> + <tag><marker id="+spp"><c>+spp Bool</c></marker></tag> + <item> + <p>Set default scheduler hint for port parallelism. If set to + <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>. + </item> <tag><marker id="sched_thread_stack_size"><c><![CDATA[+sss size]]></c></marker></tag> <item> <p>Suggested stack size, in kilowords, for scheduler threads. @@ -1072,7 +1378,7 @@ </item> </taglist> </item> - <tag><c><![CDATA[ERL_AFLAGS]]></c></tag> + <tag><marker id="ERL_AFLAGS"><c><![CDATA[ERL_AFLAGS]]></c></marker></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> @@ -1082,7 +1388,7 @@ 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><c><![CDATA[ERL_ZFLAGS]]></c> and <c><![CDATA[ERL_FLAGS]]></c></tag> + <tag><marker id="ERL_ZFLAGS"><c><![CDATA[ERL_ZFLAGS]]></c></marker> and <marker id="ERL_FLAGS"><c><![CDATA[ERL_FLAGS]]></c></marker></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> |