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authorRickard Green <[email protected]>2015-12-30 14:15:13 +0100
committerRickard Green <[email protected]>2015-12-30 14:15:13 +0100
commitdf18cd270ad682cedc8c21990641b0bdb8788092 (patch)
treeaeb8b9ccb634fb481c9a694a44994bc68f9f00cd /erts/doc
parentd32ef0d4fab9b18d34b97fd7c785bcadfe292f81 (diff)
parent37f58ad6bff2bf2bac4f3f20c2684e8cee66af03 (diff)
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Merge branch 'rickard/rq-len/OTP-13201' into maint
* rickard/rq-len/OTP-13201: Light weight statistics of run queue lengths
Diffstat (limited to 'erts/doc')
-rw-r--r--erts/doc/src/erlang.xml111
1 files changed, 99 insertions, 12 deletions
diff --git a/erts/doc/src/erlang.xml b/erts/doc/src/erlang.xml
index c37ed3bea5..64eebec936 100644
--- a/erts/doc/src/erlang.xml
+++ b/erts/doc/src/erlang.xml
@@ -5684,8 +5684,31 @@ true</pre>
<anno>Dest</anno>, <anno>Msg</anno>, [])</c></seealso>.</p>
</desc>
</func>
+
<func>
<name name="statistics" arity="1" clause_i="1"/>
+ <fsummary>Information about active processes and ports.</fsummary>
+ <desc><marker id="statistics_active_tasks"></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. 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
+ <seealso marker="#statistics_total_run_queue_lengths"><c>statistics(total_run_queue_lengths)</c></seealso>.
+ </p>
+ </desc>
+ </func>
+
+ <func>
+ <name name="statistics" arity="1" clause_i="2"/>
<fsummary>Information about context switches.</fsummary>
<desc>
<p>Returns the total number of context switches since the
@@ -5694,7 +5717,7 @@ true</pre>
</func>
<func>
- <name name="statistics" arity="1" clause_i="2"/>
+ <name name="statistics" arity="1" clause_i="3"/>
<fsummary>Information about exact reductions.</fsummary>
<desc>
<marker id="statistics_exact_reductions"></marker>
@@ -5708,7 +5731,7 @@ true</pre>
</func>
<func>
- <name name="statistics" arity="1" clause_i="3"/>
+ <name name="statistics" arity="1" clause_i="4"/>
<fsummary>Information about garbage collection.</fsummary>
<desc>
<p>Returns information about garbage collection, for example:</p>
@@ -5720,7 +5743,7 @@ true</pre>
</func>
<func>
- <name name="statistics" arity="1" clause_i="4"/>
+ <name name="statistics" arity="1" clause_i="5"/>
<fsummary>Information about I/O.</fsummary>
<desc>
<p>Returns <c><anno>Input</anno></c>,
@@ -5731,7 +5754,7 @@ true</pre>
</func>
<func>
- <name name="statistics" arity="1" clause_i="5"/>
+ <name name="statistics" arity="1" clause_i="6"/>
<fsummary>Information about reductions.</fsummary>
<desc>
<marker id="statistics_reductions"></marker>
@@ -5749,16 +5772,43 @@ true</pre>
</func>
<func>
- <name name="statistics" arity="1" clause_i="6"/>
- <fsummary>Information about the run-queue.</fsummary>
- <desc>
- <p>Returns the total length of run-queues, that is, the number
- of processes that are ready to run on all available run-queues.</p>
+ <name name="statistics" arity="1" clause_i="7"/>
+ <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
+ of processes and ports that are ready to run on all available
+ run-queues. 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"><c>statistics(total_run_queue_lengths)</c></seealso>.
+ This especially when a large amount of schedulers is used.
+ </p>
</desc>
</func>
<func>
- <name name="statistics" arity="1" clause_i="7"/>
+ <name name="statistics" arity="1" clause_i="8"/>
+ <fsummary>Information about the run-queue lengths.</fsummary>
+ <desc><marker id="statistics_run_queue_lengths"></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. See also,
+ <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
+ <seealso marker="#statistics_total_active_tasks"><c>statistics(total_active_tasks)</c></seealso>.
+ </p>
+ </desc>
+ </func>
+
+ <func>
+ <name name="statistics" arity="1" clause_i="9"/>
<fsummary>Information about runtime.</fsummary>
<desc>
<p>Returns information about runtime, in milliseconds.</p>
@@ -5773,7 +5823,7 @@ true</pre>
</func>
<func>
- <name name="statistics" arity="1" clause_i="8"/>
+ <name name="statistics" arity="1" clause_i="10"/>
<fsummary>Information about each schedulers work time.</fsummary>
<desc>
<marker id="statistics_scheduler_wall_time"></marker>
@@ -5844,7 +5894,44 @@ ok
</func>
<func>
- <name name="statistics" arity="1" clause_i="9"/>
+ <name name="statistics" arity="1" clause_i="11"/>
+ <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. 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>
+ </desc>
+ </func>
+
+ <func>
+ <name name="statistics" arity="1" clause_i="12"/>
+ <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>.
+ 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>
+ </desc>
+ </func>
+
+ <func>
+ <name name="statistics" arity="1" clause_i="13"/>
<fsummary>Information about wall clock.</fsummary>
<desc>
<p>Returns information about wall clock. <c>wall_clock</c> can