diff options
Diffstat (limited to 'lib/tools/doc/src')
| -rw-r--r-- | lib/tools/doc/src/lcnt.xml | 116 | ||||
| -rw-r--r-- | lib/tools/doc/src/lcnt_chapter.xml | 41 | ||||
| -rw-r--r-- | lib/tools/doc/src/make.xml | 2 | ||||
| -rw-r--r-- | lib/tools/doc/src/notes.xml | 57 |
4 files changed, 166 insertions, 50 deletions
diff --git a/lib/tools/doc/src/lcnt.xml b/lib/tools/doc/src/lcnt.xml index 9c8ce148e9..5bdfc60448 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>2017</year> <holder>Ericsson AB, All Rights Reserved</holder> </copyright> <legalnotice> @@ -38,7 +38,7 @@ <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 @@ -109,14 +109,6 @@ 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> @@ -322,24 +314,22 @@ <func> <name>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> + <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> @@ -357,6 +347,13 @@ 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> @@ -429,6 +426,68 @@ <desc> <p>Clear the internal counters. Same as <c>lcnt:clear(Node)</c>.</p></desc> </func> + <func> + <name>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>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>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>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> <fsummary>Same as <c>rt_opt(node(), {Type, Opt})</c>.</fsummary> @@ -442,16 +501,25 @@ <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> diff --git a/lib/tools/doc/src/lcnt_chapter.xml b/lib/tools/doc/src/lcnt_chapter.xml index 6cfdb5cf1b..24b58136aa 100644 --- a/lib/tools/doc/src/lcnt_chapter.xml +++ b/lib/tools/doc/src/lcnt_chapter.xml @@ -4,7 +4,7 @@ <chapter> <header> <copyright> - <year>2009</year><year>2016</year> + <year>2009</year><year>2017</year> <holder>Ericsson AB. All Rights Reserved.</holder> </copyright> <legalnotice> @@ -29,7 +29,7 @@ <approved>nobody</approved> <checked>no</checked> <date>2009-11-26</date> - <rev>PA1</rev> + <rev>PA2</rev> <file>lcnt_chapter.xml</file> </header> <p> @@ -42,42 +42,32 @@ completed its access to the resource and unlocked it. The <c>lcnt</c> tool measures these lock conflicts. </p> <p> - Locks has an inherent cost in execution time and memory space. It takes time initialize, destroy, aquiring or releasing locks. To decrease lock contention it + Locks have an inherent cost in execution time and memory space. It takes time initialize, destroy, aquiring or releasing locks. To decrease lock contention it some times necessary to use finer grained locking strategies. This will usually also increase the locking overhead and hence there is a tradeoff between lock contention and overhead. In general, lock contention increases with the number of threads running concurrently. The <c>lcnt</c> tool does not measure locking overhead. </p> <section> <title> Enabling lock-counting </title> - <p>For investigation of locks in the emulator we use an internal tool called <c>lcnt</c> (short for lock-count). The VM needs to be compiled with this option enabled. To enable this, use:</p> + <p>For investigation of locks in the emulator we use an internal tool called <c>lcnt</c> (short for lock-count). The VM needs to be compiled with this option enabled. + To compile a lock-counting VM along with a normal VM, use:</p> <pre> cd $ERL_TOP -./configure --enable-lock-counter - </pre> - - <p> - Another way to enable this alongside a normal VM is to compile it at emulator directory level, much like a debug build. To compile it this way do the following, - </p> - <pre> -cd $ERL_TOP/erts/emulator -make lcnt FLAVOR=smp - </pre> - <p> and then starting Erlang with,</p> +./configure --enable-lock-counter</pre> + <p>Start the lock-counting VM like this:</p> <pre> -$ERL_TOP/bin/cerl -lcnt - </pre> - <p>To verify that you lock-counting enabled check that <c>[lock-counting]</c> appears in the status text when the VM is started.</p> +$ERL_TOP/bin/erl -emu_type lcnt</pre> + <p>To verify that lock counting is enabled check that <c>[lock-counting]</c> appears in the status text when the VM is started.</p> <pre> -Erlang R13B03 (erts-5.7.4) [source] [64-bit] [smp:8:8] [rq:8] [async-threads:0] [hipe] - [kernel-poll:false] [lock-counting] - </pre> +Erlang/OTP 20 [erts-9.0] [64-bit] [smp:8:8] [ds:8:8:10] [async-threads:10] [hipe] + [kernel-poll:false] [lock-counting]</pre> </section> <section> <title>Getting started</title> <p>Once you have a lock counting enabled VM the module <c>lcnt</c> can be used. The module is intended to be used from the current running nodes shell. To access remote nodes use <c>lcnt:clear(Node)</c> and <c>lcnt:collect(Node)</c>. </p> <p>All locks are continuously monitored and its statistics updated. Use <c>lcnt:clear/0</c> to initially clear all counters before running any specific tests. This command will also reset the duration timer internally.</p> - <p>To retrieve lock statistics information use, <c>lcnt:collect/0,1</c>. The collect operation will start a <c>lcnt</c> server if it not already started. All collected data will be built into an erlang term and uploaded to the server and a duration time will also be uploaded. This duration is the time between <c>lcnt:clear/0,1</c> and <c>lcnt:collect/0,1</c>.</p> + <p>To retrieve lock statistics information, use <c>lcnt:collect/0,1</c>. The collect operation will start a <c>lcnt</c> server if it not already started. All collected data will be built into an Erlang term and uploaded to the server and a duration time will also be uploaded. This duration is the time between <c>lcnt:clear/0,1</c> and <c>lcnt:collect/0,1</c>.</p> <p>Once the data is collected to the server it can be filtered, sorted and printed in many different ways.</p> <p>See the <seealso marker="lcnt">reference manual</seealso> for a description of each function.</p> @@ -107,8 +97,11 @@ ok ok </pre> <p> - Another way to to profile a specific function is to use <c>lcnt:apply/3</c> or <c>lcnt:apply/1</c> which does <c>lcnt:clear/0</c> before the function and <c>lcnt:collect/0</c> after its invocation. - It also sets <c>copy_save</c> to <c>true</c> for the duration of the function call + Another way to to profile a specific function is to use <c>lcnt:apply/3</c> or <c>lcnt:apply/1</c> + which does <c>lcnt:clear/0</c> before the function and <c>lcnt:collect/0</c> after its invocation. + This method should only be used in micro-benchmarks since it sets <c>copy_save</c> to <c>true</c> + for the duration of the function call, which may cause the emulator to run out of memory if + attempted under load. </p> <pre> Erlang R13B03 (erts-5.7.4) [source] [smp:8:8] [rq:8] [async-threads:0] [hipe] diff --git a/lib/tools/doc/src/make.xml b/lib/tools/doc/src/make.xml index 6b878f72fb..123fcd4afc 100644 --- a/lib/tools/doc/src/make.xml +++ b/lib/tools/doc/src/make.xml @@ -5,7 +5,7 @@ <header> <copyright> <year>1996</year> - <year>2016</year> + <year>2017</year> <holder>Ericsson AB, All Rights Reserved</holder> </copyright> <legalnotice> diff --git a/lib/tools/doc/src/notes.xml b/lib/tools/doc/src/notes.xml index af20200d49..f0df43bf2b 100644 --- a/lib/tools/doc/src/notes.xml +++ b/lib/tools/doc/src/notes.xml @@ -4,7 +4,7 @@ <chapter> <header> <copyright> - <year>2004</year><year>2016</year> + <year>2004</year><year>2017</year> <holder>Ericsson AB. All Rights Reserved.</holder> </copyright> <legalnotice> @@ -31,6 +31,61 @@ </header> <p>This document describes the changes made to the Tools application.</p> +<section><title>Tools 2.10.1</title> + + <section><title>Fixed Bugs and Malfunctions</title> + <list> + <item> + <p> + In OTP-20.0, the behavior of c, make, and ct_make was + changed so that in some cases the beam files by default + would be written to the directory where the source files + were found. This is now changed back to the old behavior + so beam files are by default written to current + directory.</p> + <p> + Own Id: OTP-14489 Aux Id: ERL-438 </p> + </item> + </list> + </section> + +</section> + +<section><title>Tools 2.10</title> + + <section><title>Fixed Bugs and Malfunctions</title> + <list> + <item> + <p> + In some situations, <c>make:all()</c> and friends did not + detect changes in include files located in the current + directory. This is now corrected.</p> + <p> + Own Id: OTP-14339 Aux Id: ERL-395 </p> + </item> + </list> + </section> + + + <section><title>Improvements and New Features</title> + <list> + <item> + <p>The <c>make</c> module now accepts the + <c>{emake,Emake}</c> option.</p> + <p> + Own Id: OTP-14253</p> + </item> + <item> + <p> Miscellaneous updates due to atoms containing + arbitrary Unicode characters. </p> + <p> + Own Id: OTP-14285</p> + </item> + </list> + </section> + +</section> + <section><title>Tools 2.9.1</title> <section><title>Improvements and New Features</title> |