diff options
Diffstat (limited to 'erts/doc/src/erl.xml')
| -rw-r--r-- | erts/doc/src/erl.xml | 138 |
1 files changed, 115 insertions, 23 deletions
diff --git a/erts/doc/src/erl.xml b/erts/doc/src/erl.xml index 7cdb3a4dfe..37c7f3466b 100644 --- a/erts/doc/src/erl.xml +++ b/erts/doc/src/erl.xml @@ -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> @@ -582,13 +582,71 @@ <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> - <p><em>NOTE</em>: It is possible to choose any value in the range - but powers of 2 perform best.</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="+P"/><marker id="max_processes"><c><![CDATA[+P Number]]></c></marker></tag> + <item> + <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="+Q"/><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> @@ -621,7 +672,7 @@ <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, @@ -659,7 +710,24 @@ <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> @@ -909,6 +977,14 @@ <p>For more information, see <seealso marker="erlang#system_info_cpu_topology">erlang:system_info(cpu_topology)</seealso>.</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="+sws"><c>+sws default|legacy|proposal</c></marker></tag> <item> <p>Set scheduler wakeup strategy. Default is <c>legacy</c> (has been @@ -934,6 +1010,22 @@ 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 +1166,7 @@ </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 +1176,7 @@ 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> |