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authorRickard Green <rickard@erlang.org>2012-12-07 00:28:50 +0100
committerRickard Green <rickard@erlang.org>2012-12-07 00:28:50 +0100
commit6027f852217f0014f1892fbbfa45c69e104da652 (patch)
treebdb10abcf579b5607dc287b395fb15fa667b0512 /erts/doc/src/erlang.xml
parentd29c460c4ad1ca0cc2fb6a13a81b4ccc07516941 (diff)
parent3f85767e086e08b70baee34d719df9a8bc8814f4 (diff)
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Merge branch 'rickard/port-optimizations/OTP-10336' into rickard/r16/port-optimizations/OTP-10336
* rickard/port-optimizations/OTP-10336: Change annotate level for emacs-22 in cerl Update etp-commands Add documentation on communication in Erlang Add support for busy port message queue Add driver callback epilogue Implement true asynchronous signaling between processes and ports Add erl_drv_[send|output]_term Move busy port flag Use rwlock for driver list Optimize management of port tasks Improve configuration of process and port tables Remove R9 compatibility features Use ptab functionality also for ports Prepare for use of ptab functionality also for ports Atomic port state Generalize process table implementation Implement functionality for delaying thread progress from unmanaged threads Conflicts: erts/doc/src/erl_driver.xml erts/doc/src/erlang.xml erts/emulator/beam/beam_bif_load.c erts/emulator/beam/beam_bp.c erts/emulator/beam/beam_emu.c erts/emulator/beam/bif.c erts/emulator/beam/copy.c erts/emulator/beam/erl_alloc.c erts/emulator/beam/erl_alloc.types erts/emulator/beam/erl_bif_info.c erts/emulator/beam/erl_bif_port.c erts/emulator/beam/erl_bif_trace.c erts/emulator/beam/erl_init.c erts/emulator/beam/erl_message.c erts/emulator/beam/erl_port_task.c erts/emulator/beam/erl_process.c erts/emulator/beam/erl_process.h erts/emulator/beam/erl_process_lock.c erts/emulator/beam/erl_trace.c erts/emulator/beam/export.h erts/emulator/beam/global.h erts/emulator/beam/io.c erts/emulator/sys/unix/sys.c erts/emulator/sys/vxworks/sys.c erts/emulator/test/port_SUITE.erl erts/etc/unix/cerl.src erts/preloaded/ebin/erlang.beam erts/preloaded/ebin/prim_inet.beam erts/preloaded/src/prim_inet.erl lib/hipe/cerl/erl_bif_types.erl lib/kernel/doc/src/inet.xml lib/kernel/src/inet.erl
Diffstat (limited to 'erts/doc/src/erlang.xml')
-rw-r--r--erts/doc/src/erlang.xml338
1 files changed, 252 insertions, 86 deletions
diff --git a/erts/doc/src/erlang.xml b/erts/doc/src/erlang.xml
index 5002c48ca1..1a97a84b42 100644
--- a/erts/doc/src/erlang.xml
+++ b/erts/doc/src/erlang.xml
@@ -854,10 +854,10 @@ b</pre>
</func>
<func>
<name name="exit" arity="2"/>
- <fsummary>Send an exit signal to a process</fsummary>
+ <fsummary>Send an exit signal to a process or a port</fsummary>
<desc>
<p>Sends an exit signal with exit reason <c><anno>Reason</anno></c> to
- the process <c><anno>Pid</anno></c>.</p>
+ the process or port identified by <c><anno>Pid</anno></c>.</p>
<p>The following behavior apply if <c><anno>Reason</anno></c> is any term
except <c>normal</c> or <c>kill</c>:</p>
<p>If <c><anno>Pid</anno></c> is not trapping exits, <c><anno>Pid</anno></c> itself will
@@ -2760,6 +2760,18 @@ os_prompt% </pre>
console window when spawning the port program.
(This option has no effect on other platforms.)</p>
</item>
+ <tag><marker id="open_port_parallelism"><c>{parallelism, Boolean}</c></marker></tag>
+ <item>
+ <p>Set 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 improving the
+ latency at the expense of parallelism. The default can be set on
+ system startup by passing the
+ <seealso marker="erl#+spp">+spp</seealso> command line argument
+ to <seealso marker="erl">erl(1)</seealso>.
+ </p>
+ </item>
</taglist>
<p>The default is <c>stream</c> for all types of port and
<c>use_stdio</c> for spawned ports.</p>
@@ -2812,10 +2824,11 @@ os_prompt% </pre>
the owning process using signals of the form
<c>{'EXIT', Port, PosixCode}</c>. See <c>file(3)</c> for
possible values of <c>PosixCode</c>.</p>
- <p><marker id="ERL_MAX_PORTS"></marker>
- The maximum number of ports that can be open at the same
- time is 1024 by default, but can be configured by
- the environment variable <c>ERL_MAX_PORTS</c>.</p>
+ <p>The maximum number of ports that can be open at the same
+ time can be configured by passing the
+ <seealso marker="erl#max_ports"><c>+Q</c></seealso>
+ command line flag to
+ <seealso marker="erl"><c>erl(1)</c></seealso>.</p>
</desc>
</func>
<func>
@@ -2873,10 +2886,10 @@ os_prompt% </pre>
<desc>
<p>Closes an open port. Roughly the same as
<c><anno>Port</anno> ! {self(), close}</c> except for the error behaviour
- (see below), and that the port does <em>not</em> reply with
- <c>{Port, closed}</c>. Any process may close a port with
- <c>port_close/1</c>, not only the port owner (the connected
- process).</p>
+ (see below), being synchronous, and that the port does
+ <em>not</em> reply with <c>{Port, closed}</c>. Any process may
+ close a port with <c>port_close/1</c>, not only the port owner
+ (the connected process).</p>
<p>For comparison: <c><anno>Port</anno> ! {self(), close}</c> fails with
<c>badarg</c> if <c><anno>Port</anno></c> cannot be sent to (i.e.,
<c><anno>Port</anno></c> refers neither to a port nor to a process). If
@@ -2888,8 +2901,12 @@ os_prompt% </pre>
<p>Note that any process can close a port using
<c><anno>Port</anno> ! {PortOwner, close}</c> just as if it itself was
the port owner, but the reply always goes to the port owner.</p>
- <p>In short: <c>port_close(Port)</c> has a cleaner and more
- logical behaviour than <c><anno>Port</anno> ! {self(), close}</c>.</p>
+ <p>As of OTP-R16 <c><anno>Port</anno> ! {PortOwner, close}</c> is truly
+ asynchronous. Note that this operation has always been
+ documented as an asynchronous operation, while the underlying
+ implementation has been synchronous. <c>port_close/1</c> is
+ however still fully synchronous. This due to its error
+ behavior.</p>
<p>Failure: <c>badarg</c> if <c><anno>Port</anno></c> is not an open port or
the registered name of an open port.</p>
</desc>
@@ -2899,11 +2916,11 @@ os_prompt% </pre>
<fsummary>Send data to a port</fsummary>
<desc>
<p>Sends data to a port. Same as
- <c><anno>Port</anno> ! {self(), {command, Data}}</c> except for the error
- behaviour (see below). Any process may send data to a port
- with <c>port_command/2</c>, not only the port owner
- (the connected process).</p>
- <p>For comparison: <c><anno>Port</anno> ! {self(), {command, Data}}</c>
+ <c><anno>Port</anno> ! {PortOwner, {command, Data}}</c> except for the error
+ behaviour and being synchronous (see below). Any process may
+ send data to a port with <c>port_command/2</c>, not only the
+ port owner (the connected process).</p>
+ <p>For comparison: <c><anno>Port</anno> ! {PortOwner, {command, Data}}</c>
fails with <c>badarg</c> if <c><anno>Port</anno></c> cannot be sent to
(i.e., <c><anno>Port</anno></c> refers neither to a port nor to a process).
If <c><anno>Port</anno></c> is a closed port the data message disappears
@@ -2914,11 +2931,14 @@ os_prompt% </pre>
<p>Note that any process can send to a port using
<c><anno>Port</anno> ! {PortOwner, {command, <anno>Data</anno>}}</c> just as if it
itself was the port owner.</p>
- <p>In short: <c>port_command(<anno>Port</anno>, <anno>Data</anno>)</c> has a cleaner and
- more logical behaviour than
- <c><anno>Port</anno> ! {self(), {command, Data}}</c>.</p>
<p>If the port is busy, the calling process will be suspended
until the port is not busy anymore.</p>
+ <p>As of OTP-R16 <c><anno>Port</anno> ! {PortOwner, {command, Data}}</c> is
+ truly asynchronous. Note that this operation has always been
+ documented as an asynchronous operation, while the underlying
+ implementation has been synchronous. <c>port_command/2</c> is
+ however still fully synchronous. This due to its error
+ behavior.</p>
<p>Failures:</p>
<taglist>
<tag><c>badarg</c></tag>
@@ -2992,7 +3012,7 @@ os_prompt% </pre>
<fsummary>Set the owner of a port</fsummary>
<desc>
<p>Sets the port owner (the connected port) to <c><anno>Pid</anno></c>.
- Roughly the same as <c><anno>Port</anno> ! {self(), {connect, <anno>Pid</anno>}}</c>
+ Roughly the same as <c><anno>Port</anno> ! {Owner, {connect, <anno>Pid</anno>}}</c>
except for the following:</p>
<list type="bulleted">
<item>
@@ -3003,6 +3023,9 @@ os_prompt% </pre>
<c>{Port,connected}</c>.</p>
</item>
<item>
+ <p><c>port_connect/1</c> is synchronous, see below.</p>
+ </item>
+ <item>
<p>The new port owner gets linked to the port.</p>
</item>
</list>
@@ -3026,11 +3049,14 @@ os_prompt% </pre>
<c><anno>Port</anno> ! {PortOwner, {connect, <anno>Pid</anno>}}</c> just as if it
itself was the port owner, but the reply always goes to
the port owner.</p>
- <p>In short: <c>port_connect(<anno>Port</anno>, <anno>Pid</anno>)</c> has a cleaner and
- more logical behaviour than
- <c><anno>Port</anno> ! {self(),{connect,<anno>Pid</anno>}}</c>.</p>
+ <p>As of OTP-R16 <c><anno>Port</anno> ! {PortOwner, {connect, <anno>Pid</anno>}}</c> is
+ truly asynchronous. Note that this operation has always been
+ documented as an asynchronous operation, while the underlying
+ implementation has been synchronous. <c>port_connect/2</c> is
+ however still fully synchronous. This due to its error
+ behavior.</p>
<p>Failure: <c>badarg</c> if <c><anno>Port</anno></c> is not an open port
- or the registered name of an open port, or if <c><anno>Pid</anno></c> is
+ or the registered name of an open port, or if <c>Pid</c> is
not an existing local pid.</p>
</desc>
</func>
@@ -3077,71 +3103,187 @@ os_prompt% </pre>
</func>
<func>
<name name="port_info" arity="1"/>
- <type name="port_info_result_item"/>
<fsummary>Information about a port</fsummary>
<desc>
<p>Returns a list containing tuples with information about
the <c><anno>Port</anno></c>, or <c>undefined</c> if the port is not open.
The order of the tuples is not defined, nor are all the
tuples mandatory.</p>
- <taglist>
- <tag><c>{registered_name, <anno>RegName</anno>}</c></tag>
- <item>
- <p><c><anno>RegName</anno></c> (an atom) is the registered name of
- the port. If the port has no registered name, this tuple
- is not present in the list.</p>
- </item>
- <tag><c>{id, <anno>Index</anno>}</c></tag>
- <item>
- <p><c><anno>Index</anno></c> (an integer) is the internal index of the
- port. This index may be used to separate ports.</p>
- </item>
- <tag><c>{connected, <anno>Pid</anno>}</c></tag>
- <item>
- <p><c><anno>Pid</anno></c> is the process connected to the port.</p>
- </item>
- <tag><c>{links, <anno>Pids</anno>}</c></tag>
- <item>
- <p><c><anno>Pids</anno></c> is a list of pids to which processes the
- port is linked.</p>
- </item>
- <tag><c>{name, <anno>String</anno>}</c></tag>
- <item>
- <p><c><anno>String</anno></c> is the command name set by
- <c>open_port</c>.</p>
- </item>
- <tag><c>{input, <anno>Bytes</anno>}</c></tag>
- <item>
- <p><c><anno>Bytes</anno></c> is the total number of bytes read from
- the port.</p>
- </item>
- <tag><c>{output, <anno>Bytes</anno>}</c></tag>
- <item>
- <p><c><anno>Bytes</anno></c> is the total number of bytes written to
- the port.</p>
- </item>
- <tag><c>{os_pid, <anno>OsPid</anno> | undefined}</c></tag>
- <item>
- <p><c> <anno>OsPid</anno></c> is the process identifier (or equivalent) of an OS process created with <c>open_port({spawn | spawn_executable, Command}, Options)</c>. If the port is not the result of spawning an OS process, the value is <c>undefined</c>.</p>
- </item>
- </taglist>
- <p>Failure: <c>badarg</c> if <c><anno>Port</anno></c> is not a local port.</p>
+ <p>Currently the result will containt information about the
+ following <c>Item</c>s: <c>registered_name</c> (if the port has
+ a registered name), <c>id</c>, <c>connected</c>, <c>links</c>,
+ <c>name</c>, <c>input</c>, and <c>output</c>. For more information
+ about the different <c>Item</c>s, see
+ <seealso marker="#port_info/2">port_info/2</seealso>.</p>
+ <p>Failure: <c>badarg</c> if <c>Port</c> is not a local port
+ identifier, or an atom.</p>
</desc>
</func>
<func>
- <name name="port_info" arity="2"/>
- <type name="port_info_item"/>
- <type name="port_info_result_item"/>
- <fsummary>Information about a port</fsummary>
+ <name name="port_info" arity="2" clause_i="1"/>
+ <fsummary>Information about the connected process of a port</fsummary>
+ <desc>
+ <p><c><anno>Pid</anno></c> is the process identifier of the process
+ connected to the port.</p>
+ <p>If the port identified by <c><anno>Port</anno></c> is not open,
+ <c>undefined</c> is returned.</p>
+ <p>Failure: <c>badarg</c> if <c><anno>Port</anno></c> is not a local
+ port identifier, or an atom.</p>
+ </desc>
+ </func>
+ <func>
+ <name name="port_info" arity="2" clause_i="2"/>
+ <fsummary>Information about the internal index of a port</fsummary>
+ <desc>
+ <p><c><anno>Index</anno></c> is the internal index of the port. This
+ index may be used to separate ports.</p>
+ <p>If the port identified by <c><anno>Port</anno></c> is not open,
+ <c>undefined</c> is returned.</p>
+ <p>Failure: <c>badarg</c> if <c><anno>Port</anno></c> is not a local
+ port identifier, or an atom.</p>
+ </desc>
+ </func>
+ <func>
+ <name name="port_info" arity="2" clause_i="3"/>
+ <fsummary>Information about the input of a port</fsummary>
+ <desc>
+ <p><c><anno>Bytes</anno></c> is the total number of bytes
+ read from the port.</p>
+ <p>If the port identified by <c><anno>Port</anno></c> is not open,
+ <c>undefined</c> is returned.</p>
+ <p>Failure: <c>badarg</c> if <c><anno>Port</anno></c> is not a local
+ port identifier, or an atom.</p>
+ </desc>
+ </func>
+ <func>
+ <name name="port_info" arity="2" clause_i="4"/>
+ <fsummary>Information about the links of a port</fsummary>
+ <desc>
+ <p><c><anno>Pids</anno></c> is a list of the process identifiers
+ of the processes that the port is linked to.</p>
+ <p>If the port identified by <c><anno>Port</anno></c> is not open,
+ <c>undefined</c> is returned.</p>
+ <p>Failure: <c>badarg</c> if <c><anno>Port</anno></c> is not a local
+ port identifier, or an atom.</p>
+ </desc>
+ </func>
+ <func>
+ <name name="port_info" arity="2" clause_i="5"/>
+ <fsummary>Information about the locking of a port</fsummary>
<desc>
- <p>Returns information about <c><anno>Port</anno></c> as specified
- by <c><anno>Item</anno></c>, or <c>undefined</c> if the port is not open.
- Also, if <c>Item =:= registered_name</c> and the port has no
- registered name, <c>[]</c> is returned.</p>
- <p>For valid values of <c><anno>Item</anno></c>, and corresponding
- values of <c><anno>Result</anno></c>, see
- <seealso marker="#port_info/1">erlang:port_info/1</seealso>.</p>
- <p>Failure: <c>badarg</c> if <c><anno>Port</anno></c> is not a local port.</p>
+ <p><c><anno>Locking</anno></c> is currently either <c>false</c>
+ (emulator without SMP support), <c>port_level</c> (port specific
+ locking), or <c>driver_level</c> (driver specific locking). Note
+ that these results are highly implementation specific and might
+ change in the future.</p>
+ <p>If the port identified by <c><anno>Port</anno></c> is not open,
+ <c>undefined</c> is returned.</p>
+ <p>Failure: <c>badarg</c> if <c><anno>Port</anno></c> is not a local
+ port identifier, or an atom.</p>
+ </desc>
+ </func>
+ <func>
+ <name name="port_info" arity="2" clause_i="6"/>
+ <fsummary>Information about the memory size of a port</fsummary>
+ <desc>
+ <p><c><anno>Bytes</anno></c> is the total amount of memory,
+ in bytes, allocated for this port by the runtime system. Note
+ that the port itself might have allocated memory which is not
+ included in <c><anno>Bytes</anno></c>.</p>
+ <p>If the port identified by <c><anno>Port</anno></c> is not open,
+ <c>undefined</c> is returned.</p>
+ <p>Failure: <c>badarg</c> if <c><anno>Port</anno></c> is not a local
+ port identifier, or an atom.</p>
+ </desc>
+ </func>
+ <func>
+ <name name="port_info" arity="2" clause_i="7"/>
+ <fsummary>Information about the monitors of a port</fsummary>
+ <desc>
+ <p><c><anno>Monitors</anno></c> represent processes that this port
+ is monitoring.</p>
+ <p>If the port identified by <c><anno>Port</anno></c> is not open,
+ <c>undefined</c> is returned.</p>
+ <p>Failure: <c>badarg</c> if <c><anno>Port</anno></c> is not a local
+ port identifier, or an atom.</p>
+ </desc>
+ </func>
+ <func>
+ <name name="port_info" arity="2" clause_i="8"/>
+ <fsummary>Information about the name of a port</fsummary>
+ <desc>
+ <p><c><anno>Name</anno></c> is the command name set by
+ <seealso marker="#open_port/2">open_port/2</seealso>.</p>
+ <p>If the port identified by <c><anno>Port</anno></c> is not open,
+ <c>undefined</c> is returned.</p>
+ <p>Failure: <c>badarg</c> if <c><anno>Port</anno></c> is not a local
+ port identifier, or an atom.</p>
+ </desc>
+ </func>
+ <func>
+ <name name="port_info" arity="2" clause_i="9"/>
+ <fsummary>Information about the OS pid of a port</fsummary>
+ <desc>
+ <p><c><anno>OsPid</anno></c> is the process identifier (or equivalent)
+ of an OS process created with
+ <seealso marker="#open_port/2">open_port({spawn | spawn_executable,
+ Command}, Options)</seealso>. If the port is not the result of spawning
+ an OS process, the value is <c>undefined</c>.</p>
+ <p>If the port identified by <c><anno>Port</anno></c> is not open,
+ <c>undefined</c> is returned.</p>
+ <p>Failure: <c>badarg</c> if <c><anno>Port</anno></c> is not a local
+ port identifier, or an atom.</p>
+ </desc>
+ </func>
+ <func>
+ <name name="port_info" arity="2" clause_i="10"/>
+ <fsummary>Information about the output of a port</fsummary>
+ <desc>
+ <p><c><anno>Bytes</anno></c> is the total number of bytes written
+ to the port from Erlang processes using either
+ <seealso marker="#port_command/2">port_command/2</seealso>,
+ <seealso marker="#port_command/3">port_command/3</seealso>,
+ or <c><anno>Port</anno> ! {Owner, {command, Data}</c>.
+ </p>
+ <p>If the port identified by <c><anno>Port</anno></c> is not open,
+ <c>undefined</c> is returned.</p>
+ <p>Failure: <c>badarg</c> if <c><anno>Port</anno></c> is not a local
+ port identifier, or an atom.</p>
+ </desc>
+ </func>
+ <func>
+ <name name="port_info" arity="2" clause_i="11"/>
+ <fsummary>Information about the parallelism hint of a port</fsummary>
+ <desc>
+ <p><c><anno>Boolean</anno></c> corresponds to the port parallelism
+ hint being used by this port. For more information see
+ the <seealso marker="#open_port_parallelism">parallelism</seealso>
+ option of <seealso marker="#open_port/2">open_port/2</seealso>.</p>
+ </desc>
+ </func>
+ <func>
+ <name name="port_info" arity="2" clause_i="12"/>
+ <fsummary>Information about the queue size of a port</fsummary>
+ <desc>
+ <p><c><anno>Bytes</anno></c> is the total amount of data,
+ in bytes, queued by the port using the ERTS driver queue
+ implementation.</p>
+ <p>If the port identified by <c><anno>Port</anno></c> is not open,
+ <c>undefined</c> is returned.</p>
+ <p>Failure: <c>badarg</c> if <c><anno>Port</anno></c> is not a local
+ port identifier, or an atom.</p>
+ </desc>
+ </func>
+ <func>
+ <name name="port_info" arity="2" clause_i="13"/>
+ <fsummary>Information about the registered name of a port</fsummary>
+ <desc>
+ <p><c><anno>RegisteredName</anno></c> is the registered name of
+ the port. If the port has no registered name, <c>[]</c> is returned.</p>
+ <p>If the port identified by <c><anno>Port</anno></c> is not open,
+ <c>undefined</c> is returned.</p>
+ <p>Failure: <c>badarg</c> if <c><anno>Port</anno></c> is not a local
+ port identifier, or an atom.</p>
</desc>
</func>
<func>
@@ -3161,7 +3303,10 @@ os_prompt% </pre>
<name name="ports" arity="0"/>
<fsummary>All open ports</fsummary>
<desc>
- <p>Returns a list of all ports on the local node.</p>
+ <p>Returns a list of port identifiers corresponding to all the
+ ports currently existing on the local node.</p>
+
+ <p>Note that a port that is exiting, exists but is not open.</p>
</desc>
</func>
<func>
@@ -5494,19 +5639,40 @@ ok
<item>
<p>Returns a string containing the OTP release number.</p>
</item>
+ <tag><marker id="system_info_port_parallelism"><c>port_parallelism</c></marker></tag>
+ <item><p>Returns the default port parallelism scheduling hint used.
+ For more information see the
+ <seealso marker="erl#+spp">+spp</seealso> command line argument
+ of <seealso marker="erl">erl(1)</seealso>.</p></item>
+ <tag><c>process_count</c></tag>
+ <item>
+ <p>Returns the number of ports currently existing at
+ the local node as an integer. The same value as
+ <c>length(erlang:ports())</c> returns.</p>
+ </item>
+ <tag><marker id="system_info_port_limit"><c>port_limit</c></marker></tag>
+ <item>
+ <p>Returns the maximum number of simultaneously existing
+ ports at the local node as an integer. This limit
+ can be configured at startup by using the
+ <seealso marker="erl#max_ports"><c>+Q</c></seealso>
+ command line flag of
+ <seealso marker="erl"><c>erl(1)</c></seealso>.</p>
+ </item>
<tag><c>process_count</c></tag>
<item>
<p>Returns the number of processes currently existing at
the local node as an integer. The same value as
<c>length(processes())</c> returns.</p>
</item>
- <tag><c>process_limit</c></tag>
+ <tag><marker id="system_info_process_limit"><c>process_limit</c></marker></tag>
<item>
- <p>Returns the maximum number of concurrently existing
+ <p>Returns the maximum number of simultaneously existing
processes at the local node as an integer. This limit
- can be configured at startup by using the command line
- flag <c>+P</c>, see
- <seealso marker="erts:erl#max_processes">erl(1)</seealso>.</p>
+ can be configured at startup by using the
+ <seealso marker="erl#max_processes"><c>+P</c></seealso>
+ command line flag of
+ <seealso marker="erl"><c>erl(1)</c></seealso>.</p>
</item>
<tag><c>procs</c></tag>
<item>