diff options
Diffstat (limited to 'erts/doc/src/erlang.xml')
| -rw-r--r-- | erts/doc/src/erlang.xml | 234 |
1 files changed, 161 insertions, 73 deletions
diff --git a/erts/doc/src/erlang.xml b/erts/doc/src/erlang.xml index 6d165e9eff..105734d5b2 100644 --- a/erts/doc/src/erlang.xml +++ b/erts/doc/src/erlang.xml @@ -6148,28 +6148,60 @@ true</pre> <fsummary>Information about active processes and ports.</fsummary> <desc> <marker id="statistics_active_tasks"></marker> + <p>Returns the same as + <seealso marker="#statistics_active_tasks_all"> + <c>statistics(active_tasks_all)</c></seealso> + with the exception that no information about the dirty + IO run queue and its associated schedulers is part of + the result. That is, only tasks that are expected to be + CPU bound are part of the result.</p> + </desc> + </func> + + <func> + <name name="statistics" arity="1" clause_i="2"/> + <fsummary>Information about active processes and ports.</fsummary> + <desc> + <marker id="statistics_active_tasks_all"></marker> <p>Returns a list where each element represents the amount of active processes and ports on each run queue and its - associated scheduler. That is, the number of processes and - ports that are ready to run, or are currently running. The - element location in the list corresponds to the scheduler - and its run queue. The first element corresponds to scheduler - number 1 and so on. The information is <em>not</em> gathered - atomically. That is, the result is not necessarily a - consistent snapshot of the state, but instead quite - efficiently gathered.</p> + associated schedulers. That is, the number of processes and + ports that are ready to run, or are currently running. + Values for normal run queues and their associated schedulers + are located first in the resulting list. The first element + corresponds to scheduler number 1 and so on. If support for + dirty schedulers exist, an element with the value for the + dirty CPU run queue and its associated dirty CPU schedulers + follow and then as last element the value for the the dirty + IO run queue and its associated dirty IO schedulers follow. + The information is <em>not</em> gathered atomically. That is, + the result is not necessarily a consistent snapshot of the + state, but instead quite efficiently gathered.</p> + <note><p>Each normal scheduler has one run queue that it + manages. If dirty schedulers schedulers are supported, all + dirty CPU schedulers share one run queue, and all dirty IO + schedulers share one run queue. That is, we have multiple + normal run queues, one dirty CPU run queue and one dirty + IO run queue. Work can <em>not</em> migrate between the + different types of run queues. Only work in normal run + queues can migrate to other normal run queues. This has + to be taken into account when evaluating the result.</p></note> <p>See also <seealso marker="#statistics_total_active_tasks"> <c>statistics(total_active_tasks)</c></seealso>, <seealso marker="#statistics_run_queue_lengths"> - <c>statistics(run_queue_lengths)</c></seealso>, and + <c>statistics(run_queue_lengths)</c></seealso>, + <seealso marker="#statistics_run_queue_lengths_all"> + <c>statistics(run_queue_lengths_all)</c></seealso>, <seealso marker="#statistics_total_run_queue_lengths"> - <c>statistics(total_run_queue_lengths)</c></seealso>.</p> + <c>statistics(total_run_queue_lengths)</c></seealso>, and + <seealso marker="#statistics_total_run_queue_lengths_all"> + <c>statistics(total_run_queue_lengths_all)</c></seealso>.</p> </desc> </func> <func> - <name name="statistics" arity="1" clause_i="2"/> + <name name="statistics" arity="1" clause_i="3"/> <fsummary>Information about context switches.</fsummary> <desc> <p>Returns the total number of context switches since the @@ -6178,7 +6210,7 @@ true</pre> </func> <func> - <name name="statistics" arity="1" clause_i="3"/> + <name name="statistics" arity="1" clause_i="4"/> <fsummary>Information about exact reductions.</fsummary> <desc> <marker id="statistics_exact_reductions"></marker> @@ -6194,7 +6226,7 @@ true</pre> </func> <func> - <name name="statistics" arity="1" clause_i="4"/> + <name name="statistics" arity="1" clause_i="5"/> <fsummary>Information about garbage collection.</fsummary> <desc> <p>Returns information about garbage collection, for example:</p> @@ -6206,7 +6238,7 @@ true</pre> </func> <func> - <name name="statistics" arity="1" clause_i="5"/> + <name name="statistics" arity="1" clause_i="6"/> <fsummary>Information about I/O.</fsummary> <desc> <p>Returns <c><anno>Input</anno></c>, @@ -6217,7 +6249,7 @@ true</pre> </func> <func> - <name name="statistics" arity="1" clause_i="6"/> + <name name="statistics" arity="1" clause_i="7"/> <fsummary>Information about microstate accounting.</fsummary> <desc> <marker id="statistics_microstate_accounting"></marker> @@ -6353,7 +6385,7 @@ lists:map( </func> <func> - <name name="statistics" arity="1" clause_i="7"/> + <name name="statistics" arity="1" clause_i="8"/> <fsummary>Information about reductions.</fsummary> <desc> <marker id="statistics_reductions"></marker> @@ -6372,12 +6404,13 @@ lists:map( </func> <func> - <name name="statistics" arity="1" clause_i="8"/> + <name name="statistics" arity="1" clause_i="9"/> <fsummary>Information about the run-queues.</fsummary> <desc><marker id="statistics_run_queue"></marker> - <p>Returns the total length of the run-queues. That is, the number + <p>Returns the total length of all normal run-queues. That is, the number of processes and ports that are ready to run on all available - run-queues. The information is gathered atomically. That + normal run-queues. Dirty run queues are not part of the + result. The information is gathered atomically. That is, the result is a consistent snapshot of the state, but this operation is much more expensive compared to <seealso marker="#statistics_total_run_queue_lengths"> @@ -6387,35 +6420,72 @@ lists:map( </func> <func> - <name name="statistics" arity="1" clause_i="9"/> + <name name="statistics" arity="1" clause_i="10"/> <fsummary>Information about the run-queue lengths.</fsummary> <desc><marker id="statistics_run_queue_lengths"></marker> + <p>Returns the same as + <seealso marker="#statistics_run_queue_lengths_all"> + <c>statistics(run_queue_lengths_all)</c></seealso> + with the exception that no information about the dirty + IO run queue is part of the result. That is, only + run queues with work that is expected to be CPU bound + is part of the result.</p> + </desc> + </func> + + <func> + <name name="statistics" arity="1" clause_i="11"/> + <fsummary>Information about the run-queue lengths.</fsummary> + <desc><marker id="statistics_run_queue_lengths_all"></marker> <p>Returns a list where each element represents the amount - of processes and ports ready to run for each run queue. The - element location in the list corresponds to the run queue - of a scheduler. The first element corresponds to the run - queue of scheduler number 1 and so on. The information is - <em>not</em> gathered atomically. That is, the result is - not necessarily a consistent snapshot of the state, but - instead quite efficiently gathered.</p> + of processes and ports ready to run for each run queue. + Values for normal run queues are located first in the + resulting list. The first element corresponds to the + normal run queue of scheduler number 1 and so on. If + support for dirty schedulers exist, values for the dirty + CPU run queue and the dirty IO run queue follow (in that + order) at the end. The information is <em>not</em> + gathered atomically. That is, the result is not + necessarily a consistent snapshot of the state, but + instead quite efficiently gathered.</p> + <note><p>Each normal scheduler has one run queue that it + manages. If dirty schedulers schedulers are supported, all + dirty CPU schedulers share one run queue, and all dirty IO + schedulers share one run queue. That is, we have multiple + normal run queues, one dirty CPU run queue and one dirty + IO run queue. Work can <em>not</em> migrate between the + different types of run queues. Only work in normal run + queues can migrate to other normal run queues. This has + to be taken into account when evaluating the result.</p></note> <p>See also + <seealso marker="#statistics_run_queue_lengths"> + <c>statistics(run_queue_lengths)</c></seealso>, + <seealso marker="#statistics_total_run_queue_lengths_all"> + <c>statistics(total_run_queue_lengths_all)</c></seealso>, <seealso marker="#statistics_total_run_queue_lengths"> <c>statistics(total_run_queue_lengths)</c></seealso>, <seealso marker="#statistics_active_tasks"> - <c>statistics(active_tasks)</c></seealso>, and + <c>statistics(active_tasks)</c></seealso>, + <seealso marker="#statistics_active_tasks_all"> + <c>statistics(active_tasks_all)</c></seealso>, and <seealso marker="#statistics_total_active_tasks"> - <c>statistics(total_active_tasks)</c></seealso>.</p> + <c>statistics(total_active_tasks)</c></seealso>, + <seealso marker="#statistics_total_active_tasks_all"> + <c>statistics(total_active_tasks_all)</c></seealso>.</p> </desc> </func> <func> - <name name="statistics" arity="1" clause_i="10"/> + <name name="statistics" arity="1" clause_i="12"/> <fsummary>Information about runtime.</fsummary> <desc> <p>Returns information about runtime, in milliseconds.</p> <p>This is the sum of the runtime for all threads in the Erlang runtime system and can therefore be greater than the wall clock time.</p> + <warning><p>This value might wrap due to limitations in the + underlying functionality provided by the operating system + that is used.</p></warning> <p>Example:</p> <pre> > <input>statistics(runtime).</input> @@ -6424,7 +6494,7 @@ lists:map( </func> <func> - <name name="statistics" arity="1" clause_i="11"/> + <name name="statistics" arity="1" clause_i="13"/> <fsummary>Information about each schedulers work time.</fsummary> <desc> <marker id="statistics_scheduler_wall_time"></marker> @@ -6545,7 +6615,7 @@ ok </func> <func> - <name name="statistics" arity="1" clause_i="12"/> + <name name="statistics" arity="1" clause_i="14"/> <fsummary>Information about each schedulers work time.</fsummary> <desc> <marker id="statistics_scheduler_wall_time_all"></marker> @@ -6570,47 +6640,47 @@ ok </desc> </func> <func> - <name name="statistics" arity="1" clause_i="13"/> + <name name="statistics" arity="1" clause_i="15"/> <fsummary>Information about active processes and ports.</fsummary> <desc><marker id="statistics_total_active_tasks"></marker> - <p>Returns the total amount of active processes and ports in - the system. That is, the number of processes and ports that - are ready to run, or are currently running. The information - is <em>not</em> gathered atomically. That is, the result - is not necessarily a consistent snapshot of the state, but - instead quite efficiently gathered.</p> - <p>See also - <seealso marker="#statistics_active_tasks"> - <c>statistics(active_tasks)</c></seealso>, - <seealso marker="#statistics_run_queue_lengths"> - <c>statistics(run_queue_lengths)</c></seealso>, and - <seealso marker="#statistics_total_run_queue_lengths"> - <c>statistics(total_run_queue_lengths)</c></seealso>.</p> + <p>The same as calling + <c>lists:sum(</c><seealso marker="#statistics_active_tasks"><c>statistics(active_tasks)</c></seealso><c>)</c>, + but more efficient.</p> </desc> </func> <func> - <name name="statistics" arity="1" clause_i="14"/> + <name name="statistics" arity="1" clause_i="16"/> + <fsummary>Information about active processes and ports.</fsummary> + <desc><marker id="statistics_total_active_tasks_all"></marker> + <p>The same as calling + <c>lists:sum(</c><seealso marker="#statistics_active_tasks_all"><c>statistics(active_tasks_all)</c></seealso><c>)</c>, + but more efficient.</p> + </desc> + </func> + + <func> + <name name="statistics" arity="1" clause_i="17"/> <fsummary>Information about the run-queue lengths.</fsummary> <desc><marker id="statistics_total_run_queue_lengths"></marker> - <p>Returns the total length of the run queues. That is, the number - of processes and ports that are ready to run on all available - run queues. The information is <em>not</em> gathered atomically. - That is, the result is not necessarily a consistent snapshot of - the state, but much more efficiently gathered compared to - <seealso marker="#statistics_run_queue"> - <c>statistics(run_queue)</c></seealso>.</p> - <p>See also <seealso marker="#statistics_run_queue_lengths"> - <c>statistics(run_queue_lengths)</c></seealso>, - <seealso marker="#statistics_total_active_tasks"> - <c>statistics(total_active_tasks)</c></seealso>, and - <seealso marker="#statistics_active_tasks"> - <c>statistics(active_tasks)</c></seealso>.</p> + <p>The same as calling + <c>lists:sum(</c><seealso marker="#statistics_run_queue_lengths"><c>statistics(run_queue_lengths)</c></seealso><c>)</c>, + but more efficient.</p> </desc> </func> <func> - <name name="statistics" arity="1" clause_i="15"/> + <name name="statistics" arity="1" clause_i="18"/> + <fsummary>Information about the run-queue lengths.</fsummary> + <desc><marker id="statistics_total_run_queue_lengths_all"></marker> + <p>The same as calling + <c>lists:sum(</c><seealso marker="#statistics_run_queue_lengths_all"><c>statistics(run_queue_lengths_all)</c></seealso><c>)</c>, + but more efficient.</p> + </desc> + </func> + + <func> + <name name="statistics" arity="1" clause_i="19"/> <fsummary>Information about wall clock.</fsummary> <desc> <p>Returns information about wall clock. <c>wall_clock</c> can @@ -8793,18 +8863,36 @@ hello <p>Option <c>{minor_version, <anno>Version</anno>}</c> can be used to control some encoding details. This option was introduced in Erlang/OTP R11B-4. - The valid values for <c><anno>Version</anno></c> are - <c>0</c> and <c>1</c>.</p> - <p>As from Erlang/OTP 17.0, <c>{minor_version, 1}</c> is the default. It - forces any floats in the term to be encoded in a more - space-efficient and exact way (namely in the 64-bit IEEE format, - rather than converted to a textual representation).</p> - <p>As from Erlang/OTP R11B-4, <c>binary_to_term/1</c> can decode this - representation.</p> - <p><c>{minor_version, 0}</c> means that floats are encoded - using a textual representation. This option is useful to - ensure that releases before Erlang/OTP R11B-4 can decode resulting - binary.</p> + The valid values for <c><anno>Version</anno></c> are:</p> + <taglist> + <tag><c>0</c></tag> + <item> + <p>Floats are encoded using a textual representation. + This option is useful to ensure that releases before Erlang/OTP + R11B-4 can decode resulting binary.</p> + <p>This version encode atoms that can be represented by a + latin1 string using latin1 encoding while only atoms that + cannot be represented by latin1 are encoded using utf8.</p> + </item> + <tag><c>1</c></tag> + <item> + <p>This is as of Erlang/OTP 17.0 the default. It forces any floats + in the term to be encoded in a more space-efficient and exact way + (namely in the 64-bit IEEE format, rather than converted to a + textual representation). As from Erlang/OTP R11B-4, + <c>binary_to_term/1</c> can decode this representation.</p> + <p>This version encode atoms that can be represented by a + latin1 string using latin1 encoding while only atoms that + cannot be represented by latin1 are encoded using utf8.</p> + </item> + <tag><c>2</c></tag> + <item> + <p>Drops usage of the latin1 atom encoding and unconditionally + use utf8 encoding for all atoms. This will be changed to the + default in a future major release of Erlang/OTP. Erlang/OTP + systems as of R16B can decode this representation.</p> + </item> + </taglist> <p>See also <seealso marker="#binary_to_term/1"> <c>binary_to_term/1</c></seealso>.</p> </desc> |