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-rw-r--r--lib/tools/doc/src/lcnt.xml178
1 files changed, 123 insertions, 55 deletions
diff --git a/lib/tools/doc/src/lcnt.xml b/lib/tools/doc/src/lcnt.xml
index 9c8ce148e9..1d434decfc 100644
--- a/lib/tools/doc/src/lcnt.xml
+++ b/lib/tools/doc/src/lcnt.xml
@@ -5,7 +5,7 @@
<header>
<copyright>
<year>2009</year>
- <year>2016</year>
+ <year>2018</year>
<holder>Ericsson AB, All Rights Reserved</holder>
</copyright>
<legalnotice>
@@ -34,11 +34,11 @@
<rev>PA1</rev>
<file>lcnt.xml</file>
</header>
- <module>lcnt</module>
+ <module since="OTP R13B04">lcnt</module>
<modulesummary>A runtime system Lock Profiling tool.</modulesummary>
<description>
<p>The <c>lcnt</c> module is used to profile the internal ethread locks in the
- Erlang Runtime System. With <c>lcnt</c> enabled, Internal counters in the
+ Erlang Runtime System. With <c>lcnt</c> enabled, internal counters in the
runtime system are updated each time a lock is taken. The counters stores
information about the number of acquisition tries and the number of collisions
that has occurred during the acquisition tries. The counters also record the
@@ -47,17 +47,17 @@
<p>
The data produced by the lock counters will give an estimate on how well
the runtime system will behave from a parallelizable view point for the
- scenarios tested. This tool was mainly developed to help erlang runtime
+ scenarios tested. This tool was mainly developed to help Erlang runtime
developers iron out potential and generic bottlenecks.
</p>
<p>Locks in the emulator are named after what type of resource they protect and where
in the emulator they are initialized, those are lock 'classes'. Most of those
locks are also instantiated several times, and given unique identifiers, to increase
locking granularity. Typically an instantiated lock protects a disjunct set of
- the resource, i.e ets-tables, processes or ports. In other cases it protects a
- specific range of a resource, e.g. <c>pix_lock</c> which protects index to process
+ the resource, for example ets tables, processes or ports. In other cases it protects a
+ specific range of a resource, for example <c>pix_lock</c> which protects index to process
mappings, and is given a unique number within the class. A unique lock in <c>lcnt</c>
- is referenced by a name (class) and an identifier, <c>{Name, Id}</c>.
+ is referenced by a name (class) and an identifier: <c>{Name, Id}</c>.
</p>
<p>Some locks in the system are static and protects global resources, for example
<c>bif_timers</c> and the <c>run_queue</c> locks. Other locks are dynamic and not
@@ -71,7 +71,7 @@
<funcs>
<func>
- <name>start() -> {ok, Pid} | {error, {already_started, Pid}} </name>
+ <name since="OTP R13B04">start() -> {ok, Pid} | {error, {already_started, Pid}} </name>
<fsummary>Starts the lock profiler server.</fsummary>
<type>
<v>Pid = pid()</v>
@@ -84,7 +84,7 @@
</func>
<func>
- <name>stop() -> ok</name>
+ <name since="OTP R13B04">stop() -> ok</name>
<fsummary>Stops the lock profiler server.</fsummary>
<desc>
<p>Stops the lock profiler server.</p>
@@ -92,13 +92,13 @@
</func>
<func>
- <name>collect() -> ok</name>
+ <name since="OTP R13B04">collect() -> ok</name>
<fsummary>Same as <c>collect(node())</c>.</fsummary>
<desc><p>Same as <c>collect(node())</c>.</p></desc>
</func>
<func>
- <name>collect(Node) -> ok</name>
+ <name since="OTP R13B04">collect(Node) -> ok</name>
<fsummary>Collects lock statistics from the runtime system.</fsummary>
<type>
<v>Node = node()</v>
@@ -109,25 +109,17 @@
statistics. If the server held any lock statistics data before the collect then
that data is lost.
</p>
- <note>
- <p>
- When collection occurs the runtime system transitions to a single thread,
- blocking all other threads. No other tasks will be scheduled during this
- operation. Depending on the size of the data this might take a long time
- (several seconds) and cause timeouts in the system.
- </p>
- </note>
</desc>
</func>
<func>
- <name>clear() -> ok</name>
+ <name since="OTP R13B04">clear() -> ok</name>
<fsummary>Same as <c>clear(node())</c>.</fsummary>
<desc><p>Same as <c>clear(node())</c>.</p></desc>
</func>
<func>
- <name>clear(Node) -> ok</name>
+ <name since="OTP R13B04">clear(Node) -> ok</name>
<fsummary>Clears the internal lock statistics from runtime system.</fsummary>
<type>
<v>Node = node()</v>
@@ -141,12 +133,12 @@
</desc>
</func>
<func>
- <name>conflicts() -> ok</name>
+ <name since="OTP R13B04">conflicts() -> ok</name>
<fsummary>Same as <c>conflicts([])</c>.</fsummary>
<desc><p>Same as <c>conflicts([])</c>.</p></desc>
</func>
<func>
- <name>conflicts([Option]) -> ok</name>
+ <name since="OTP R13B04">conflicts([Option]) -> ok</name>
<fsummary>Prints a list of internal lock counters.</fsummary>
<type>
<v>Option = {sort, Sort} | {reverse, bool()} | {thresholds, [Thresholds]} | {print, [Print | {Print, integer()}]} | {max_locks, MaxLocks} | {combine, bool()}</v>
@@ -162,14 +154,14 @@
</func>
<func>
- <name>locations() -> ok</name>
+ <name since="OTP R13B04">locations() -> ok</name>
<fsummary>Same as <c>locations([])</c>.</fsummary>
<desc>
<p>Same as <c>locations([])</c>.</p>
</desc>
</func>
<func>
- <name>locations([Option]) -> ok</name>
+ <name since="OTP R13B04">locations([Option]) -> ok</name>
<fsummary>Prints a list of internal lock counters by source code locations.</fsummary>
<type>
<v>Option = {sort, Sort} | {thresholds, [Thresholds]} | {print, [Print | {Print, integer()}]} | {max_locks, MaxLocks} | {combine, bool()}</v>
@@ -185,12 +177,12 @@
</func>
<func>
- <name>inspect(Lock) -> ok</name>
+ <name since="OTP R13B04">inspect(Lock) -> ok</name>
<fsummary>Same as <c>inspect(Lock, [])</c>.</fsummary>
<desc><p>Same as <c>inspect(Lock, [])</c>.</p></desc>
</func>
<func>
- <name>inspect(Lock, [Option]) -> ok</name>
+ <name since="OTP R13B04">inspect(Lock, [Option]) -> ok</name>
<fsummary>Prints a list of internal lock counters for a specific lock.</fsummary>
<type>
<v>Lock = Name | {Name, Id | [Id]}</v>
@@ -276,7 +268,7 @@
</func>
<func>
- <name>information() -> ok</name>
+ <name since="OTP R13B04">information() -> ok</name>
<fsummary>Prints lcnt server state and generic information about collected lock statistics.</fsummary>
<desc>
<p>Prints lcnt server state and generic information about collected lock statistics.</p>
@@ -284,7 +276,7 @@
</func>
<func>
- <name>swap_pid_keys() -> ok</name>
+ <name since="OTP R13B04">swap_pid_keys() -> ok</name>
<fsummary>Swaps places on <c>Name</c> and <c>Id</c> space for ports and processes.</fsummary>
<desc>
<p>Swaps places on <c>Name</c> and <c>Id</c> space for ports and processes.</p>
@@ -292,7 +284,7 @@
</func>
<func>
- <name>load(Filename) -> ok</name>
+ <name since="OTP R13B04">load(Filename) -> ok</name>
<fsummary>Restores previously saved data to the server.</fsummary>
<type>
<v>Filename = filename()</v>
@@ -303,7 +295,7 @@
</func>
<func>
- <name>save(Filename) -> ok</name>
+ <name since="OTP R13B04">save(Filename) -> ok</name>
<fsummary>Saves the collected data to file.</fsummary>
<type>
<v>Filename = filename()</v>
@@ -320,30 +312,28 @@
</section>
<funcs>
<func>
- <name>apply(Fun) -> term()</name>
+ <name since="OTP R13B04">apply(Fun) -> term()</name>
<fsummary>Same as <c>apply(Fun, [])</c>.</fsummary>
+ <type>
+ <v>Fun = fun()</v>
+ </type>
<desc>
<p>Same as <c>apply(Fun, [])</c>.</p>
</desc>
</func>
<func>
- <name>apply(Fun, Args) -> term()</name>
- <fsummary>Clears counters, applies function and collects the profiling results.</fsummary>
+ <name since="OTP R13B04">apply(Fun, Args) -> term()</name>
+ <fsummary>Same as <c>apply(Module, Function, Args)</c>.</fsummary>
<type>
<v>Fun = fun()</v>
<v>Args = [term()]</v>
</type>
<desc>
- <p> Clears the lock counters and then setups the instrumentation to save all destroyed locks.
- After setup the fun is called, passing the elements in <c>Args</c> as arguments.
- When the fun returns the statistics are immediately collected to the server. After the
- collection the instrumentation is returned to its previous behavior.
- The result of the applied fun is returned.
- </p>
+ <p>Same as <c>apply(Module, Function, Args)</c>.</p>
</desc>
</func>
<func>
- <name>apply(Module, Function, Args) -> term()</name>
+ <name since="OTP R13B04">apply(Module, Function, Args) -> term()</name>
<fsummary>Clears counters, applies function and collects the profiling results.</fsummary>
<type>
<v>Module = atom()</v>
@@ -357,16 +347,23 @@
collection the instrumentation is returned to its previous behavior.
The result of the applied function is returned.
</p>
+ <warning>
+ <p>
+ This function should only be used for micro-benchmarks; it sets <c>copy_save</c>
+ to <c>true</c> for the duration of the call, which can quickly lead to running
+ out of memory.
+ </p>
+ </warning>
</desc>
</func>
<func>
- <name>pid(Id, Serial) -> pid()</name>
+ <name since="OTP R13B04">pid(Id, Serial) -> pid()</name>
<fsummary>Same as <c>pid(node(), Id, Serial)</c>.</fsummary>
<desc><p>Same as <c>pid(node(), Id, Serial)</c>.</p></desc>
</func>
<func>
- <name>pid(Node, Id, Serial) -> pid()</name>
+ <name since="OTP R13B04">pid(Node, Id, Serial) -> pid()</name>
<fsummary>Creates a process id with creation 0.</fsummary>
<type>
<v>Node = node()</v>
@@ -374,17 +371,17 @@
<v>Serial = integer()</v>
</type>
<desc>
- <p>Creates a process id with creation 0. Example:</p>
+ <p>Creates a process id with creation 0.</p>
</desc>
</func>
<func>
- <name>port(Id) -> port()</name>
+ <name since="OTP R13B04">port(Id) -> port()</name>
<fsummary>Same as <c>port(node(), Id)</c>.</fsummary>
<desc><p>Same as <c>port(node(), Id)</c>.</p></desc>
</func>
<func>
- <name>port(Node, Id) -> port()</name>
+ <name since="OTP R13B04">port(Node, Id) -> port()</name>
<fsummary>Creates a port id with creation 0.</fsummary>
<type>
<v>Node = node()</v>
@@ -402,12 +399,12 @@
<funcs>
<func>
- <name>rt_collect() -> [lock_counter_data()]</name>
+ <name since="OTP R13B04">rt_collect() -> [lock_counter_data()]</name>
<fsummary>Same as <c>rt_collect(node())</c>.</fsummary>
<desc> <p>Same as <c>rt_collect(node())</c>.</p> </desc>
</func>
<func>
- <name>rt_collect(Node) -> [lock_counter_data()]</name>
+ <name since="OTP R13B04">rt_collect(Node) -> [lock_counter_data()]</name>
<fsummary>Returns a list of raw lock counter data.</fsummary>
<type>
<v>Node = node()</v>
@@ -416,12 +413,12 @@
</func>
<func>
- <name>rt_clear() -> ok</name>
+ <name since="OTP R13B04">rt_clear() -> ok</name>
<fsummary>Same as <c>rt_clear(node())</c>.</fsummary>
<desc> <p>Same as <c>rt_clear(node())</c>.</p> </desc>
</func>
<func>
- <name>rt_clear(Node) -> ok</name>
+ <name since="OTP R13B04">rt_clear(Node) -> ok</name>
<fsummary>Clears the internal counters.</fsummary>
<type>
<v>Node = node()</v>
@@ -429,29 +426,100 @@
<desc> <p>Clear the internal counters. Same as <c>lcnt:clear(Node)</c>.</p></desc>
</func>
+ <func>
+ <name since="OTP 20.1">rt_mask() -> [category_atom()]</name>
+ <fsummary>Same as <c>rt_mask(node())</c>.</fsummary>
+ <desc><p>Same as <c>rt_mask(node())</c>.</p></desc>
+ </func>
+
+ <func>
+ <name since="OTP 20.1">rt_mask(Node) -> [category_atom()]</name>
+ <fsummary>Returns the current lock category mask.</fsummary>
+ <type>
+ <v>Node = node()</v>
+ </type>
+ <desc>
+ <p>
+ Refer to <c>rt_mask/2</c> for a list of valid categories. All
+ categories are enabled by default.
+ </p>
+ </desc>
+ </func>
+
+ <func>
+ <name since="OTP 20.1">rt_mask(Categories) -> ok | {error, copy_save_enabled}</name>
+ <fsummary>Same as <c>rt_mask(node(), Categories)</c>.</fsummary>
+ <type>
+ <v>Categories = [atom()]</v>
+ </type>
+ <desc><p>Same as <c>rt_mask(node(), Categories)</c>.</p></desc>
+ </func>
+
+ <func>
+ <name since="OTP 20.1">rt_mask(Node, Categories) -> ok | {error, copy_save_enabled}</name>
+ <fsummary>Changes the lock category mask.</fsummary>
+ <type>
+ <v>Node = node()</v>
+ <v>Categories = [atom()]</v>
+ </type>
+ <desc>
+ <p>
+ Sets the lock category mask to the given categories.
+ </p>
+ <p>
+ This will fail if the <c>copy_save</c> option is enabled; see
+ <c>lcnt:rt_opt/2</c>.
+ </p>
+ <p>Valid categories are:</p>
+ <list>
+ <item><c>allocator</c></item>
+ <item><c>db</c> (ETS tables)</item>
+ <item><c>debug</c></item>
+ <item><c>distribution</c></item>
+ <item><c>generic</c></item>
+ <item><c>io</c></item>
+ <item><c>process</c></item>
+ <item><c>scheduler</c></item>
+ </list>
+ <p>
+ This list is subject to change at any time, as is the category any given lock
+ may belong to.
+ </p>
+ </desc>
+ </func>
+
<func>
- <name>rt_opt({Type, bool()}) -> bool()</name>
+ <name since="OTP R13B04">rt_opt({Type, bool()}) -> bool()</name>
<fsummary>Same as <c>rt_opt(node(), {Type, Opt})</c>.</fsummary>
<desc> <p>Same as <c>rt_opt(node(), {Type, Opt})</c>.</p> </desc>
</func>
<func>
- <name>rt_opt(Node, {Type, bool()}) -> bool()</name>
+ <name since="OTP R13B04">rt_opt(Node, {Type, bool()}) -> bool()</name>
<fsummary>Changes the lock counter behavior and returns the previous behaviour.</fsummary>
<type>
<v>Node = node()</v>
<v>Type = copy_save | process_locks</v>
</type>
<desc>
- <p>Changes the lock counter behavior and returns the previous behaviour.</p>
<p>Option description:</p>
<taglist>
<tag><c>{copy_save, bool()}</c></tag>
- <item>Enable statistics saving from destroyed locks by copying. This might consume a lot of memory.
+ <item>Retains the statistics of destroyed locks.
<br/>Default: <c>false</c>
+ <warning>
+ <p>
+ This option will use a lot of memory when enabled, which must be
+ reclaimed with <c>lcnt:rt_clear</c>. Note that it makes no distinction
+ between locks that were destroyed and locks for which counting was
+ disabled, so enabling this option will disable changes to the lock
+ category mask.
+ </p>
+ </warning>
</item>
<tag><c>{process_locks, bool()}</c></tag>
- <item>Profile process locks.
+ <item>Profile process locks, equal to adding <c>process</c> to the lock category mask;
+ see <c>lcnt:rt_mask/2</c>
<br/>Default: <c>true</c>
</item>
</taglist>
generated by cgit v1.2.3 (git 2.25.1) at 2025-01-22 01:31:05 +0000