diff options
Diffstat (limited to 'erts/doc/src/erl.xml')
| -rw-r--r-- | erts/doc/src/erl.xml | 103 |
1 files changed, 85 insertions, 18 deletions
diff --git a/erts/doc/src/erl.xml b/erts/doc/src/erl.xml index 7cdb3a4dfe..99f2466d79 100644 --- a/erts/doc/src/erl.xml +++ b/erts/doc/src/erl.xml @@ -582,13 +582,71 @@ <seealso marker="erts_alloc">erts_alloc(3)</seealso> for further information.</p> </item> + <tag><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="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> - <p><em>NOTE</em>: It is possible to choose any value in the range - but powers of 2 perform best.</p> + <p>Sets the maximum number of simultaneously existing processes for this + system. 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> + </item> + <tag><marker id="max_ports"><c><![CDATA[+Q Number]]></c></marker></tag> + <item> + <p>Sets the maximum number of simultaneously existing ports for this + system. 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>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> </item> <tag><marker id="compat_rel"><c><![CDATA[+R ReleaseNumber]]></c></marker></tag> <item> @@ -597,21 +655,14 @@ 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> @@ -934,6 +985,22 @@ 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 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>. + 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. @@ -1074,7 +1141,7 @@ </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> @@ -1084,7 +1151,7 @@ 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> |