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authorRickard Green <rickard@erlang.org>2012-10-31 23:31:50 +0100
committerRickard Green <rickard@erlang.org>2012-12-03 21:18:07 +0100
commit7e789df8dd9c7d86e9cc354521a37aa598aa5ec8 (patch)
tree9fee41a6df34f7bb26ce1020f6f3333bd2665d90 /erts/doc
parentef302baca81ceaedbfb128fae60a42e53910f061 (diff)
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Improve configuration of process and port tables
Diffstat (limited to 'erts/doc')
-rw-r--r--erts/doc/src/erl.xml67
-rw-r--r--erts/doc/src/erlang.xml35
2 files changed, 75 insertions, 27 deletions
diff --git a/erts/doc/src/erl.xml b/erts/doc/src/erl.xml
index 4ef3e089a6..f7d8d37fd3 100644
--- a/erts/doc/src/erl.xml
+++ b/erts/doc/src/erl.xml
@@ -586,13 +586,51 @@
<seealso marker="erts_alloc">erts_alloc(3)</seealso> for
further information.</p>
</item>
+ <tag><c><![CDATA[+n]]></c></tag>
+ <item>
+ <p>Enable synchronous message passing to ports.</p>
+ <p>As of OTP-R16 message passing to ports are truly asynchronously
+ implemented. Correctly written Erlang programs should be able
+ to handle this without any issues. Bugs in existing Erlang
+ programs that make false assumptions about message passing 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 this flag is
+ deprecated as of its introduction, and is scheduled for removal
+ in OTP-R17.</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>
+ <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>
@@ -601,21 +639,14 @@
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>
@@ -1026,7 +1057,7 @@
the given number of seconds have elapsed, the emulator will be
terminated by a SIGALRM signal.</p>
</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>
@@ -1036,7 +1067,7 @@
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>
diff --git a/erts/doc/src/erlang.xml b/erts/doc/src/erlang.xml
index 0963904b83..2da456d49f 100644
--- a/erts/doc/src/erlang.xml
+++ b/erts/doc/src/erlang.xml
@@ -3225,10 +3225,11 @@ 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>
@@ -5955,17 +5956,33 @@ ok
</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>