diff options
Diffstat (limited to 'erts/doc/src/erlang.xml')
| -rw-r--r-- | erts/doc/src/erlang.xml | 409 |
1 files changed, 352 insertions, 57 deletions
diff --git a/erts/doc/src/erlang.xml b/erts/doc/src/erlang.xml index 81e9084e07..124302a2cb 100644 --- a/erts/doc/src/erlang.xml +++ b/erts/doc/src/erlang.xml @@ -235,7 +235,7 @@ <code> 1> Bin = <<1,2,3,4,5,6,7,8,9,10>>. -2> binary_part(Bin,{byte_size(Bin), -5)). +2> binary_part(Bin,{byte_size(Bin), -5}). <<6,7,8,9,10>> </code> @@ -501,16 +501,87 @@ <name name="check_process_code" arity="2"/> <fsummary>Check if a process is executing old code for a module</fsummary> <desc> - <p>Returns <c>true</c> if the process <c><anno>Pid</anno></c> is executing - old code for <c><anno>Module</anno></c>. That is, if the current call of - the process executes old code for this module, or if the - process has references to old code for this module, or if the - process contains funs that references old code for this - module. Otherwise, it returns <c>false</c>.</p> - <pre> -> <input>check_process_code(Pid, lists).</input> -false</pre> + <p>The same as + <seealso marker="#check_process_code/3"><c>erlang:check_process_code(<anno>Pid</anno>, + <anno>Module</anno>, [])</c></seealso>.</p> + </desc> + </func> + <func> + <name name="check_process_code" arity="3"/> + <fsummary>Check if a process is executing old code for a module</fsummary> + <desc> + <p>Check if the node local process identified by <c><anno>Pid</anno></c> + is executing old code for <c><anno>Module</anno></c>.</p> + <p>Currently available <c><anno>Option</anno>s</c>:</p> + <taglist> + <tag><c>{allow_gc, boolean()}</c></tag> + <item> + Determines if garbage collection is allowed when performing + the operation. If <c>{allow_gc, false}</c> is passed, and + a garbage collection is needed in order to determine the + result of the operation, the operation will be aborted + (see information on <c><anno>CheckResult</anno></c> below). + The default is to allow garbage collection, i.e., + <c>{allow_gc, true}</c>. + </item> + <tag><c>{async, RequestId}</c></tag> + <item> + The <c>check_process_code/3</c> function will return + the value <c>async</c> immediately after the request + has been sent. When the request has been processed, the + process that called this function will be passed a + message on the form:<br/> + <c>{check_process_code, <anno>RequestId</anno>, <anno>CheckResult</anno>}</c>. + </item> + </taglist> + <p>If <c><anno>Pid</anno></c> equals <c>self()</c>, and + no <c>async</c> option has been passed, the operation will + be performed at once. In all other cases a request for + the operation will be sent to the process identified by + <c><anno>Pid</anno></c>, and will be handled when + appropriate. If no <c>async</c> option has been passed, + the caller will block until <c><anno>CheckResult</anno></c> + is available and can be returned.</p> + <p><c><anno>CheckResult</anno></c> informs about the result of + the request:</p> + <taglist> + <tag><c>true</c></tag> + <item> + The process identified by <c><anno>Pid</anno></c> is + executing old code for <c><anno>Module</anno></c>. + That is, the current call of the process executes old + code for this module, or the process has references + to old code for this module, or the process contains + funs that references old code for this module. + </item> + <tag><c>false</c></tag> + <item> + The process identified by <c><anno>Pid</anno></c> is + not executing old code for <c><anno>Module</anno></c>. + </item> + <tag><c>aborted</c></tag> + <item> + The operation was aborted since the process needed to + be garbage collected in order to determine the result + of the operation, and the operation was requested + by passing the <c>{allow_gc, false}</c> option.</item> + </taglist> <p>See also <seealso marker="kernel:code">code(3)</seealso>.</p> + <p>Failures:</p> + <taglist> + <tag><c>badarg</c></tag> + <item> + If <c><anno>Pid</anno></c> is not a node local process identifier. + </item> + <tag><c>badarg</c></tag> + <item> + If <c><anno>Module</anno></c> is not an atom. + </item> + <tag><c>badarg</c></tag> + <item> + If <c><anno>OptionList</anno></c> is not a valid list of options. + </item> + </taglist> </desc> </func> <func> @@ -1197,20 +1268,74 @@ true that the spontaneous garbage collection will occur too late or not at all. Improper use may seriously degrade system performance.</p> - <p>Compatibility note: In versions of OTP prior to R7, - the garbage collection took place at the next context switch, - not immediately. To force a context switch after a call to - <c>erlang:garbage_collect()</c>, it was sufficient to make - any function call.</p> </desc> </func> <func> <name name="garbage_collect" arity="1"/> - <fsummary>Force an immediate garbage collection of a process</fsummary> + <fsummary>Garbage collect a process</fsummary> <desc> - <p>Works like <c>erlang:garbage_collect()</c> but on any - process. The same caveats apply. Returns <c>false</c> if - <c><anno>Pid</anno></c> refers to a dead process; <c>true</c> otherwise.</p> + <p>The same as + <seealso marker="#garbage_collect/2"><c>garbage_collect(<anno>Pid</anno>, [])</c></seealso>.</p> + </desc> + </func> + <func> + <name name="garbage_collect" arity="2"/> + <fsummary>Garbage collect a process</fsummary> + <desc> + <p>Garbage collect the node local process identified by + <c><anno>Pid</anno></c>.</p> + <p>Currently available <c><anno>Option</anno></c>s:</p> + <taglist> + <tag><c>{async, RequestId}</c></tag> + <item> + The <c>garbage_collect/2</c> function will return + the value <c>async</c> immediately after the request + has been sent. When the request has been processed, the + process that called this function will be passed a + message on the form:<br/> + <c>{garbage_collect, <anno>RequestId</anno>, <anno>GCResult</anno>}</c>. + </item> + </taglist> + <p>If <c><anno>Pid</anno></c> equals <c>self()</c>, and + no <c>async</c> option has been passed, the garbage + collection will be performed at once, i.e. the same as + calling + <seealso marker="#garbage_collect/0">garbage_collect/0</seealso>. + In all other cases a request for garbage collection will + be sent to the process identified by <c><anno>Pid</anno></c>, + and will be handled when appropriate. If no <c>async</c> + option has been passed, the caller will block until + <c><anno>GCResult</anno></c> is available and can be + returned.</p> + <p><c><anno>GCResult</anno></c> informs about the result of + the garbage collection request:</p> + <taglist> + <tag><c>true</c></tag> + <item> + The process identified by <c><anno>Pid</anno></c> has + been garbage collected. + </item> + <tag><c>false</c></tag> + <item> + No garbage collection was performed. This since the + the process identified by <c><anno>Pid</anno></c> + terminated before the request could be satisfied. + </item> + </taglist> + <p>Note that the same caveats as for + <seealso marker="#garbage_collect/0">garbage_collect/0</seealso> + apply.</p> + <p>Failures:</p> + <taglist> + <tag><c>badarg</c></tag> + <item> + If <c><anno>Pid</anno></c> is not a node local process identifier. + </item> + <tag><c>badarg</c></tag> + <item> + If <c><anno>OptionList</anno></c> is not a valid list of options. + </item> + </taglist> </desc> </func> <func> @@ -2467,7 +2592,7 @@ os_prompt% </pre> fails, a <c>nodedown</c> message is delivered.</p> <p>Nodes connected through hidden connections can be monitored as any other node.</p> - <p>Failure: <c>badarg</c>if the local node is not alive.</p> + <p>Failure: <c>badarg</c> if the local node is not alive.</p> </desc> </func> <func> @@ -3012,7 +3137,10 @@ os_prompt% </pre> (see below), being synchronous, and that the port does <em>not</em> reply with <c>{Port, closed}</c>. Any process may close a port with <c>port_close/1</c>, not only the port owner - (the connected process).</p> + (the connected process). If the calling process is linked to + port identified by <c><anno>Port</anno></c>, an exit signal due + to that link will be received by the process prior to the return + from <c>port_close/1</c>.</p> <p>For comparison: <c><anno>Port</anno> ! {self(), close}</c> fails with <c>badarg</c> if <c><anno>Port</anno></c> cannot be sent to (i.e., <c><anno>Port</anno></c> refers neither to a port nor to a process). If @@ -3021,6 +3149,7 @@ os_prompt% </pre> the port replies with <c>{Port, closed}</c> when all buffers have been flushed and the port really closes, but if the calling process is not the port owner the <em>port owner</em> fails with <c>badsig</c>.</p> + <p>Note that any process can close a port using <c><anno>Port</anno> ! {PortOwner, close}</c> just as if it itself was the port owner, but the reply always goes to the port owner.</p> @@ -3030,8 +3159,17 @@ os_prompt% </pre> implementation has been synchronous. <c>port_close/1</c> is however still fully synchronous. This due to its error behavior.</p> - <p>Failure: <c>badarg</c> if <c><anno>Port</anno></c> is not an open port or - the registered name of an open port.</p> + <p>Failure:</p> + <taglist> + <tag><c>badarg</c></tag> + <item> + If <c><anno>Port</anno></c> is not an identifier of an open + port, or the registered name of an open port. If the calling + process was linked to the previously open port identified by + <c><anno>Port</anno></c>, an exit signal due to this link + was received by the process prior to this exception. + </item> + </taglist> </desc> </func> <func> @@ -3066,8 +3204,11 @@ os_prompt% </pre> <taglist> <tag><c>badarg</c></tag> <item> - If <c><anno>Port</anno></c> is not an open port or the registered name - of an open port. + If <c><anno>Port</anno></c> is not an identifier of an open + port, or the registered name of an open port. If the calling + process was linked to the previously open port identified by + <c><anno>Port</anno></c>, an exit signal due to this link + was received by the process prior to this exception. </item> <tag><c>badarg</c></tag> <item> @@ -3110,8 +3251,11 @@ os_prompt% </pre> <taglist> <tag><c>badarg</c></tag> <item> - If <c><anno>Port</anno></c> is not an open port or the registered name - of an open port. + If <c><anno>Port</anno></c> is not an identifier of an open + port, or the registered name of an open port. If the calling + process was linked to the previously open port identified by + <c><anno>Port</anno></c>, an exit signal due to this link + was received by the process prior to this exception. </item> <tag><c>badarg</c></tag> <item> @@ -3178,9 +3322,20 @@ os_prompt% </pre> implementation has been synchronous. <c>port_connect/2</c> is however still fully synchronous. This due to its error behavior.</p> - <p>Failure: <c>badarg</c> if <c><anno>Port</anno></c> is not an open port - or the registered name of an open port, or if <c>Pid</c> is - not an existing local pid.</p> + <p>Failures:</p> + <taglist> + <tag><c>badarg</c></tag> + <item> + If <c><anno>Port</anno></c> is not an identifier of an open + port, or the registered name of an open port. If the calling + process was linked to the previously open port identified by + <c><anno>Port</anno></c>, an exit signal due to this link + was received by the process prior to this exception. + </item> + <tag><c>badarg</c></tag> + <item>If process identified by <c>Pid</c> is not an existing + local process.</item> + </taglist> </desc> </func> <func> @@ -3216,12 +3371,33 @@ os_prompt% </pre> binary term format and sent to the port.</p> <p>Returns: a term from the driver. The meaning of the returned data also depends on the port driver.</p> - <p>Failure: <c>badarg</c> if <c><anno>Port</anno></c> is not an open port or - the registered name of an open port, if <c><anno>Operation</anno></c> - cannot fit in a 32-bit integer, if the port driver does not - support synchronous control operations, or if the port driver - so decides for any reason (probably something wrong with - <c><anno>Operation</anno></c> or <c><anno>Data</anno></c>).</p> + <p>Failures:</p> + <taglist> + <tag><c>badarg</c></tag> + <item> + If <c><anno>Port</anno></c> is not an identifier of an open + port, or the registered name of an open port. If the calling + process was linked to the previously open port identified by + <c><anno>Port</anno></c>, an exit signal due to this link + was received by the process prior to this exception. + </item> + <tag><c>badarg</c></tag> + <item> + If <c><anno>Operation</anno></c> does not fit in a + 32-bit integer. + </item> + <tag><c>badarg</c></tag> + <item> + If the port driver does not support synchronous control + operations. + </item> + <tag><c>badarg</c></tag> + <item> + If the port driver so decides for any reason (probably + something wrong with <c><anno>Operation</anno></c>, or + <c><anno>Data</anno></c>). + </item> + </taglist> </desc> </func> <func> @@ -3231,7 +3407,12 @@ os_prompt% </pre> <p>Returns a list containing tuples with information about the <c><anno>Port</anno></c>, or <c>undefined</c> if the port is not open. The order of the tuples is not defined, nor are all the - tuples mandatory.</p> + tuples mandatory. + If <c>undefined</c> is returned and the calling process + was linked to a previously open port identified by + <c><anno>Port</anno></c>, an exit signal due to this link + was received by the process prior to the return from + <c>port_info/1</c>.</p> <p>Currently the result will containt information about the following <c>Item</c>s: <c>registered_name</c> (if the port has a registered name), <c>id</c>, <c>connected</c>, <c>links</c>, @@ -3249,7 +3430,11 @@ os_prompt% </pre> <p><c><anno>Pid</anno></c> is the process identifier of the process connected to the port.</p> <p>If the port identified by <c><anno>Port</anno></c> is not open, - <c>undefined</c> is returned.</p> + <c>undefined</c> is returned. If <c>undefined</c> is returned and + the calling process was linked to a previously open port identified + by <c><anno>Port</anno></c>, an exit signal due to this link + was received by the process prior to the return from + <c>port_info/2</c>.</p> <p>Failure: <c>badarg</c> if <c><anno>Port</anno></c> is not a local port identifier, or an atom.</p> </desc> @@ -3261,7 +3446,11 @@ os_prompt% </pre> <p><c><anno>Index</anno></c> is the internal index of the port. This index may be used to separate ports.</p> <p>If the port identified by <c><anno>Port</anno></c> is not open, - <c>undefined</c> is returned.</p> + <c>undefined</c> is returned. If <c>undefined</c> is returned and + the calling process was linked to a previously open port identified + by <c><anno>Port</anno></c>, an exit signal due to this link + was received by the process prior to the return from + <c>port_info/2</c>.</p> <p>Failure: <c>badarg</c> if <c><anno>Port</anno></c> is not a local port identifier, or an atom.</p> </desc> @@ -3273,7 +3462,11 @@ os_prompt% </pre> <p><c><anno>Bytes</anno></c> is the total number of bytes read from the port.</p> <p>If the port identified by <c><anno>Port</anno></c> is not open, - <c>undefined</c> is returned.</p> + <c>undefined</c> is returned. If <c>undefined</c> is returned and + the calling process was linked to a previously open port identified + by <c><anno>Port</anno></c>, an exit signal due to this link + was received by the process prior to the return from + <c>port_info/2</c>.</p> <p>Failure: <c>badarg</c> if <c><anno>Port</anno></c> is not a local port identifier, or an atom.</p> </desc> @@ -3285,7 +3478,11 @@ os_prompt% </pre> <p><c><anno>Pids</anno></c> is a list of the process identifiers of the processes that the port is linked to.</p> <p>If the port identified by <c><anno>Port</anno></c> is not open, - <c>undefined</c> is returned.</p> + <c>undefined</c> is returned. If <c>undefined</c> is returned and + the calling process was linked to a previously open port identified + by <c><anno>Port</anno></c>, an exit signal due to this link + was received by the process prior to the return from + <c>port_info/2</c>.</p> <p>Failure: <c>badarg</c> if <c><anno>Port</anno></c> is not a local port identifier, or an atom.</p> </desc> @@ -3300,7 +3497,11 @@ os_prompt% </pre> that these results are highly implementation specific and might change in the future.</p> <p>If the port identified by <c><anno>Port</anno></c> is not open, - <c>undefined</c> is returned.</p> + <c>undefined</c> is returned. If <c>undefined</c> is returned and + the calling process was linked to a previously open port identified + by <c><anno>Port</anno></c>, an exit signal due to this link + was received by the process prior to the return from + <c>port_info/2</c>.</p> <p>Failure: <c>badarg</c> if <c><anno>Port</anno></c> is not a local port identifier, or an atom.</p> </desc> @@ -3314,7 +3515,11 @@ os_prompt% </pre> that the port itself might have allocated memory which is not included in <c><anno>Bytes</anno></c>.</p> <p>If the port identified by <c><anno>Port</anno></c> is not open, - <c>undefined</c> is returned.</p> + <c>undefined</c> is returned. If <c>undefined</c> is returned and + the calling process was linked to a previously open port identified + by <c><anno>Port</anno></c>, an exit signal due to this link + was received by the process prior to the return from + <c>port_info/2</c>.</p> <p>Failure: <c>badarg</c> if <c><anno>Port</anno></c> is not a local port identifier, or an atom.</p> </desc> @@ -3326,7 +3531,11 @@ os_prompt% </pre> <p><c><anno>Monitors</anno></c> represent processes that this port is monitoring.</p> <p>If the port identified by <c><anno>Port</anno></c> is not open, - <c>undefined</c> is returned.</p> + <c>undefined</c> is returned. If <c>undefined</c> is returned and + the calling process was linked to a previously open port identified + by <c><anno>Port</anno></c>, an exit signal due to this link + was received by the process prior to the return from + <c>port_info/2</c>.</p> <p>Failure: <c>badarg</c> if <c><anno>Port</anno></c> is not a local port identifier, or an atom.</p> </desc> @@ -3338,7 +3547,11 @@ os_prompt% </pre> <p><c><anno>Name</anno></c> is the command name set by <seealso marker="#open_port/2">open_port/2</seealso>.</p> <p>If the port identified by <c><anno>Port</anno></c> is not open, - <c>undefined</c> is returned.</p> + <c>undefined</c> is returned. If <c>undefined</c> is returned and + the calling process was linked to a previously open port identified + by <c><anno>Port</anno></c>, an exit signal due to this link + was received by the process prior to the return from + <c>port_info/2</c>.</p> <p>Failure: <c>badarg</c> if <c><anno>Port</anno></c> is not a local port identifier, or an atom.</p> </desc> @@ -3353,7 +3566,11 @@ os_prompt% </pre> Command}, Options)</seealso>. If the port is not the result of spawning an OS process, the value is <c>undefined</c>.</p> <p>If the port identified by <c><anno>Port</anno></c> is not open, - <c>undefined</c> is returned.</p> + <c>undefined</c> is returned. If <c>undefined</c> is returned and + the calling process was linked to a previously open port identified + by <c><anno>Port</anno></c>, an exit signal due to this link + was received by the process prior to the return from + <c>port_info/2</c>.</p> <p>Failure: <c>badarg</c> if <c><anno>Port</anno></c> is not a local port identifier, or an atom.</p> </desc> @@ -3369,7 +3586,11 @@ os_prompt% </pre> or <c><anno>Port</anno> ! {Owner, {command, Data}</c>. </p> <p>If the port identified by <c><anno>Port</anno></c> is not open, - <c>undefined</c> is returned.</p> + <c>undefined</c> is returned. If <c>undefined</c> is returned and + the calling process was linked to a previously open port identified + by <c><anno>Port</anno></c>, an exit signal due to this link + was received by the process prior to the return from + <c>port_info/2</c>.</p> <p>Failure: <c>badarg</c> if <c><anno>Port</anno></c> is not a local port identifier, or an atom.</p> </desc> @@ -3392,7 +3613,11 @@ os_prompt% </pre> in bytes, queued by the port using the ERTS driver queue implementation.</p> <p>If the port identified by <c><anno>Port</anno></c> is not open, - <c>undefined</c> is returned.</p> + <c>undefined</c> is returned. If <c>undefined</c> is returned and + the calling process was linked to a previously open port identified + by <c><anno>Port</anno></c>, an exit signal due to this link + was received by the process prior to the return from + <c>port_info/2</c>.</p> <p>Failure: <c>badarg</c> if <c><anno>Port</anno></c> is not a local port identifier, or an atom.</p> </desc> @@ -3404,7 +3629,11 @@ os_prompt% </pre> <p><c><anno>RegisteredName</anno></c> is the registered name of the port. If the port has no registered name, <c>[]</c> is returned.</p> <p>If the port identified by <c><anno>Port</anno></c> is not open, - <c>undefined</c> is returned.</p> + <c>undefined</c> is returned. If <c>undefined</c> is returned and + the calling process was linked to a previously open port identified + by <c><anno>Port</anno></c>, an exit signal due to this link + was received by the process prior to the return from + <c>port_info/2</c>.</p> <p>Failure: <c>badarg</c> if <c><anno>Port</anno></c> is not a local port identifier, or an atom.</p> </desc> @@ -4707,8 +4936,8 @@ true</pre> <name name="statistics" arity="1" clause_i="6"/> <fsummary>Information about the run-queue</fsummary> <desc> - <p>Returns the length of the run queue, that is, the number - of processes that are ready to run.</p> + <p>Returns the total length of the run queues, that is, the number + of processes that are ready to run on all available run queues.</p> </desc> </func> <func> @@ -5296,7 +5525,11 @@ ok As of erts version 5.6.1 the return value is a list of <c>{instance, InstanceNo, InstanceInfo}</c> tuples where <c>InstanceInfo</c> contains information about - a specific instance of the allocator. + a specific instance of the allocator. As of erts version + 5.10.4 the returned list when calling + <c>erlang:system_info({allocator, mseg_alloc})</c> also + include an <c>{erts_mmap, _}</c> tuple as one element + in the list. If <c><anno>Alloc</anno></c> is not a recognized allocator, <c>undefined</c> is returned. If <c><anno>Alloc</anno></c> is disabled, <c>false</c> is returned.</p> @@ -5480,6 +5713,9 @@ ok <name name="system_info" arity="1" clause_i="49"/> <name name="system_info" arity="1" clause_i="50"/> <name name="system_info" arity="1" clause_i="51"/> + <name name="system_info" arity="1" clause_i="52"/> + <name name="system_info" arity="1" clause_i="53"/> + <name name="system_info" arity="1" clause_i="54"/> <fsummary>Information about the system</fsummary> <desc> <p>Returns various information about the current system @@ -5556,6 +5792,13 @@ ok 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><marker id="system_info_dist_buf_busy_limit"><c>dist_buf_busy_limit</c></marker></tag> + <item> + <p>Returns the value of the distribution buffer busy limit + in bytes. This limit can be set on startup by passing the + <seealso marker="erts:erl#+zdbbl">+zdbbl</seealso> command line + flag to <c>erl</c>.</p> + </item> <tag><c>dist_ctrl</c></tag> <item> <p>Returns a list of tuples @@ -5602,12 +5845,14 @@ ok The return value will always be <c>false</c> since the elib_malloc allocator has been removed.</p> </item> - <tag><marker id="system_info_dist_buf_busy_limit"><c>dist_buf_busy_limit</c></marker></tag> + <tag><c>ets_limit</c></tag> <item> - <p>Returns the value of the distribution buffer busy limit - in bytes. This limit can be set on startup by passing the - <seealso marker="erts:erl#+zdbbl">+zdbbl</seealso> command line - flag to <c>erl</c>.</p> + <p>Returns the maximum number of ETS tables allowed. This limit + can be increased on startup by passing the <seealso + marker="erts:erl#+e">+e</seealso> command line flag to + <c>erl</c> or by setting the environment variable + <c>ERL_MAX_ETS_TABLES</c> before starting the Erlang runtime + system.</p> </item> <tag><c>fullsweep_after</c></tag> <item> @@ -5763,6 +6008,13 @@ ok <seealso marker="#system_info_multi_scheduling">erlang:system_info(multi_scheduling)</seealso>, and <seealso marker="#system_info_schedulers">erlang:system_info(schedulers)</seealso>.</p> </item> + <tag><marker id="system_info_otp_correction_package"><c>otp_correction_package</c></marker></tag> + <item> + <p>Returns a string containing the OTP correction package version + number that currenly executing VM is part of. Note that other + OTP applications in the system may be part of other OTP correction + packages.</p> + </item> <tag><marker id="system_info_otp_release"><c>otp_release</c></marker></tag> <item> <p>Returns a string containing the OTP release number.</p> @@ -6038,6 +6290,49 @@ ok notice. </p> </item> + <tag><c>{long_schedule, Time}</c></tag> + <item> + <p>If a process or port in the system runs uninterrupted + for at least <c>Time</c> wall clock milliseconds, a + message <c>{monitor, PidOrPort, long_schedule, Info}</c> + is sent to <c>MonitorPid</c>. <c>PidOrPort</c> is the + process or port that was running and <c>Info</c> is a + list of two-element tuples describing the event. In case + of a <c>pid()</c>, the tuples <c>{timeout, Millis}</c>, + <c>{in, Location}</c> and <c>{out, Location}</c> will be + present, where <c>Location</c> is either an MFA + (<c>{Module, Function, Arity}</c>) describing the + function where the process was scheduled in/out, or the + atom <c>undefined</c>. In case of a <c>port()</c>, the + tuples <c>{timeout, Millis}</c> and <c>{port_op,Op}</c> + will be present. <c>Op</c> will be one of <c>proc_sig</c>, + <c>timeout</c>, <c>input</c>, <c>output</c>, + <c>event</c> or <c>dist_cmd</c>, depending on which + driver callback was executing. <c>proc_sig</c> is an + internal operation and should never appear, while the + others represent the corresponding driver callbacks + <c>timeout</c>, <c>ready_input</c>, <c>ready_output</c>, + <c>event</c> and finally <c>outputv</c> (when the port + is used by distribution). The <c>Millis</c> value in + the <c>timeout</c> tuple will tell you the actual + uninterrupted execution time of the process or port, + which will always be <c>>=</c> the <c>Time</c> value + supplied when starting the trace. New tuples may be + added to the <c>Info</c> list in the future, and the + order of the tuples in the list may be changed at any + time without prior notice. + </p> + <p>This can be used to detect problems with NIF's or + drivers that take too long to execute. Generally, 1 ms + is considered a good maximum time for a driver callback + or a NIF. However, a time sharing system should usually + consider everything below 100 ms as "possible" and + fairly "normal". Schedule times above that might however + indicate swapping or a NIF/driver that is + misbehaving. Misbehaving NIF's and drivers could cause + bad resource utilization and bad overall performance of + the system.</p> + </item> <tag><c>{large_heap, Size}</c></tag> <item> <p>If a garbage collection in the system results in |