diff options
Diffstat (limited to 'erts/doc')
| -rw-r--r-- | erts/doc/src/erl.xml | 22 | ||||
| -rw-r--r-- | erts/doc/src/erlang.xml | 144 |
2 files changed, 94 insertions, 72 deletions
diff --git a/erts/doc/src/erl.xml b/erts/doc/src/erl.xml index df80142ce1..f477280a6f 100644 --- a/erts/doc/src/erl.xml +++ b/erts/doc/src/erl.xml @@ -603,6 +603,24 @@ <item> <p>Force ets memory block to be moved on realloc.</p> </item> + <tag><marker id="+rg"><c><![CDATA[+rg ReaderGroupsLimit]]></c></marker></tag> + <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> + <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, + schedulers share reader groups. Shared reader groups degrades + read lock and read unlock performance while a large amount of + reader groups degrades write lock performance, so the limit is a + tradeoff between performance for read operations and performance + for write operations. Each reader group currently consumes 64 byte + in each read/write lock. Also note that a runtime system using + shared reader groups benefits from <seealso marker="#+sbt">binding + schedulers to logical processors</seealso>, since the reader groups + are distributed better between schedulers.</p> + </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 @@ -667,8 +685,8 @@ <seealso marker="erlang#system_flag_scheduler_bind_type">erlang:system_flag(scheduler_bind_type, default_bind)</seealso>. </p></item> </taglist> - <p>Binding of schedulers are currently only supported on newer - Linux and Solaris systems.</p> + <p>Binding of schedulers is currently only supported on newer + Linux, Solaris, and Windows systems.</p> <p>If no CPU topology is available when the <c>+sbt</c> flag is processed and <c>BindType</c> is any other type than <c>u</c>, the runtime system will fail to start. CPU diff --git a/erts/doc/src/erlang.xml b/erts/doc/src/erlang.xml index 77a628e82b..5d8a96a910 100644 --- a/erts/doc/src/erlang.xml +++ b/erts/doc/src/erlang.xml @@ -499,7 +499,7 @@ iolist() = [char() | binary() | iolist()] <name>erlang:cancel_timer(TimerRef) -> Time | false</name> <fsummary>Cancel a timer</fsummary> <type> - <v>TimerRef = ref()</v> + <v>TimerRef = reference()</v> <v>Time = int()</v> </type> <desc> @@ -763,7 +763,7 @@ false</pre> <name>erlang:demonitor(MonitorRef) -> true</name> <fsummary>Stop monitoring</fsummary> <type> - <v>MonitorRef = ref()</v> + <v>MonitorRef = reference()</v> </type> <desc> <p>If <c>MonitorRef</c> is a reference which the calling process @@ -803,7 +803,7 @@ false</pre> <name>erlang:demonitor(MonitorRef, OptionList) -> true|false</name> <fsummary>Stop monitoring</fsummary> <type> - <v>MonitorRef = ref()</v> + <v>MonitorRef = reference()</v> <v>OptionList = [Option]</v> <v>Option = flush</v> <v>Option = info</v> @@ -2160,7 +2160,7 @@ os_prompt%</pre> </desc> </func> <func> - <name>make_ref() -> ref()</name> + <name>make_ref() -> reference()</name> <fsummary>Return an almost unique reference</fsummary> <desc> <p>Returns an almost unique reference.</p> @@ -2690,7 +2690,7 @@ os_prompt%</pre> <name>node(Arg) -> Node</name> <fsummary>At which node is a pid, port or reference located</fsummary> <type> - <v>Arg = pid() | port() | ref()</v> + <v>Arg = pid() | port() | reference()</v> <v>Node = node()</v> </type> <desc> @@ -2767,8 +2767,10 @@ os_prompt%</pre> Otherwise, some other point in time is chosen. It is also guaranteed that subsequent calls to this BIF returns continuously increasing values. Hence, the return value from - <c>now()</c> can be used to generate unique time-stamps. It - can only be used to check the local time of day if + <c>now()</c> can be used to generate unique time-stamps, + and if it is called in a tight loop on a fast machine + the time of the node can become skewed.</p> + <p>It can only be used to check the local time of day if the time-zone info of the underlying operating system is properly configured.</p> </desc> @@ -4096,7 +4098,7 @@ os_prompt%</pre> <name>erlang:read_timer(TimerRef) -> int() | false</name> <fsummary>Number of milliseconds remaining for a timer</fsummary> <type> - <v>TimerRef = ref()</v> + <v>TimerRef = reference()</v> </type> <desc> <p><c>TimerRef</c> is a timer reference returned by @@ -4119,7 +4121,7 @@ os_prompt%</pre> <name>erlang:ref_to_list(Ref) -> string()</name> <fsummary>Text representation of a reference</fsummary> <type> - <v>Ref = ref()</v> + <v>Ref = reference()</v> </type> <desc> <p>Returns a string which corresponds to the text @@ -4298,7 +4300,7 @@ true</pre> <v>Dest = pid() | RegName </v> <v> LocalPid = pid() (of a process, alive or dead, on the local node)</v> <v>Msg = term()</v> - <v>TimerRef = ref()</v> + <v>TimerRef = reference()</v> </type> <desc> <p>Starts a timer which will send the message <c>Msg</c> @@ -4827,7 +4829,7 @@ true</pre> <v> LocalPid = pid() (of a process, alive or dead, on the local node)</v> <v> RegName = atom()</v> <v>Msg = term()</v> - <v>TimerRef = ref()</v> + <v>TimerRef = reference()</v> </type> <desc> <p>Starts a timer which will send the message @@ -5173,9 +5175,9 @@ true</pre> schedulers actually have bound as requested, call <seealso marker="#system_info_scheduler_bindings">erlang:system_info(scheduler_bindings)</seealso>. </p> - <p>Schedulers can currently only be bound on newer Linux - and Solaris systems, but more systems will be supported - in the future. + <p>Schedulers can currently only be bound on newer Linux, + Solaris, and Windows systems, but more systems will be + supported in the future. </p> <p>In order for the runtime system to be able to bind schedulers, the CPU topology needs to be known. If the runtime system fails @@ -5362,7 +5364,7 @@ true</pre> <p>Returns <c>{Allocator, Version, Features, Settings}.</c></p> <p>Types:</p> <list type="bulleted"> - <item><c>Allocator = undefined | elib_malloc | glibc</c></item> + <item><c>Allocator = undefined | glibc</c></item> <item><c>Version = [int()]</c></item> <item><c>Features = [atom()]</c></item> <item><c>Settings = [{Subsystem, [{Parameter, Value}]}]</c></item> @@ -5377,7 +5379,7 @@ true</pre> implementation used. If <c>Allocator</c> equals <c>undefined</c>, the <c>malloc()</c> implementation used could not be identified. Currently - <c>elib_malloc</c> and <c>glibc</c> can be identified.</p> + <c>glibc</c> can be identified.</p> </item> <item> <p><c>Version</c> is a list of integers (but not a @@ -5531,7 +5533,7 @@ true</pre> <c>CpuTopology</c> type to change. </p> </item> - <tag><c>{cpu_topology, defined}</c></tag> + <tag><marker id="system_info_cpu_topology_defined"><c>{cpu_topology, defined}</c></marker></tag> <item> <p>Returns the user defined <c>CpuTopology</c>. For more information see the documentation of @@ -5541,12 +5543,14 @@ true</pre> argument. </p> </item> - <tag><c>{cpu_topology, detected}</c></tag> + <tag><marker id="system_info_cpu_topology_detected"><c>{cpu_topology, detected}</c></marker></tag> <item> <p>Returns the automatically detected <c>CpuTopology</c>. The emulator currently only detects the CPU topology on some newer - linux and solaris systems. For more information see the - documentation of the + Linux, Solaris, and Windows systems. On Windows system with + more than 32 logical processors the CPU topology is not detected. + </p> + <p>For more information see the documentation of the <seealso marker="#system_info_cpu_topology">cpu_topology</seealso> argument. </p> @@ -5604,52 +5608,9 @@ true</pre> </item> <tag><c>elib_malloc</c></tag> <item> - <p>If the emulator uses the <c>elib_malloc</c> memory - allocator, a list of two-element tuples containing status - information is returned; otherwise, <c>false</c> is - returned. The list currently contains the following - two-element tuples (all sizes are presented in bytes):</p> - <taglist> - <tag><c>{heap_size, Size}</c></tag> - <item> - <p>Where <c>Size</c> is the current heap size.</p> - </item> - <tag><c>{max_alloced_size, Size}</c></tag> - <item> - <p>Where <c>Size</c> is the maximum amount of memory - allocated on the heap since the emulator started.</p> - </item> - <tag><c>{alloced_size, Size}</c></tag> - <item> - <p>Where <c>Size</c> is the current amount of memory - allocated on the heap.</p> - </item> - <tag><c>{free_size, Size}</c></tag> - <item> - <p>Where <c>Size</c> is the current amount of free - memory on the heap.</p> - </item> - <tag><c>{no_alloced_blocks, No}</c></tag> - <item> - <p>Where <c>No</c> is the current number of allocated - blocks on the heap.</p> - </item> - <tag><c>{no_free_blocks, No}</c></tag> - <item> - <p>Where <c>No</c> is the current number of free blocks - on the heap.</p> - </item> - <tag><c>{smallest_alloced_block, Size}</c></tag> - <item> - <p>Where <c>Size</c> is the size of the smallest - allocated block on the heap.</p> - </item> - <tag><c>{largest_free_block, Size}</c></tag> - <item> - <p>Where <c>Size</c> is the size of the largest free - block on the heap.</p> - </item> - </taglist> + <p>This option will be removed in a future release. + The return value will always be <c>false</c> since + the elib_malloc allocator has been removed.</p> </item> <tag><c>fullsweep_after</c></tag> <item> @@ -5725,11 +5686,34 @@ true</pre> information see the <seealso marker="erts:crash_dump">"How to interpret the Erlang crash dumps"</seealso> chapter in the ERTS User's Guide.</p> </item> - <tag><c>logical_processors</c></tag> + <tag><marker id="logical_processors"><c>logical_processors</c></marker></tag> <item> - <p>Returns the number of logical processors detected on the - system as an integer or the atom <c>unknown</c> if the - emulator wasn't able to detect any. + <p>Returns the detected number of logical processors configured + on the system. The return value is either an integer, or + the atom <c>unknown</c> if the emulator wasn't able to + detect logical processors configured. + </p> + </item> + <tag><marker id="logical_processors_available"><c>logical_processors_available</c></marker></tag> + <item> + <p>Returns the detected number of logical processors available to + the Erlang runtime system. The return value is either an + integer, or the atom <c>unknown</c> if the emulator wasn't + able to detect logical processors available. The number + of logical processors available is less than or equal to + the number of <seealso marker="#logical_processors_online">logical + processors online</seealso>. + </p> + </item> + <tag><marker id="logical_processors_online"><c>logical_processors_online</c></marker></tag> + <item> + <p>Returns the detected number of logical processors online on + the system. The return value is either an integer, + or the atom <c>unknown</c> if the emulator wasn't able to + detect logical processors online. The number of logical + processors online is less than or equal to the number of + <seealso marker="#logical_processors">logical processors + configured</seealso>. </p> </item> <tag><c>machine</c></tag> @@ -5934,6 +5918,26 @@ true</pre> <c>get_tcw</c> in "Match Specifications in Erlang", <seealso marker="erts:match_spec#get_tcw">ERTS User's Guide</seealso>.</p> </item> + <tag><marker id="update_cpu_info"><c>update_cpu_info</c></marker></tag> + <item> + <p>The runtime system rereads the CPU information available and + updates its internally stored information about the + <seealso marker="#system_info_cpu_topology_detected">detected CPU + topology</seealso> and the amount of logical processors + <seealso marker="#logical_processors">configured</seealso>, + <seealso marker="#logical_processors_online">online</seealso>, and + <seealso marker="#logical_processors_available">available</seealso>. + If the CPU information has changed since the last time it was read, + the atom <c>changed</c> is returned; otherwise, the atom + <c>unchanged</c> is returned. If the CPU information has changed + you probably want to + <seealso marker="#system_flag_schedulers_online">adjust the amount + of schedulers online</seealso>. You typically want to have as + many schedulers online as + <seealso marker="#logical_processors_available">logical processors + available</seealso>. + </p> + </item> <tag><marker id="system_info_version"><c>version</c></marker></tag> <item> <p>Returns a string containing the version number of the |