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diff --git a/erts/doc/src/notes.xml b/erts/doc/src/notes.xml index 2b2898f0c1..7501ccd9ce 100644 --- a/erts/doc/src/notes.xml +++ b/erts/doc/src/notes.xml @@ -32,699 +32,6 @@ <p>This document describes the changes made to the ERTS application.</p> -<section><title>Erts 8.0</title> - - <section><title>Fixed Bugs and Malfunctions</title> - <list> - <item> - <p>The handling of <c>on_load</c> functions has been - improved. The major improvement is that if a code upgrade - fails because the <c>on_load</c> function fails, the - previous version of the module will now be retained.</p> - <p> - Own Id: OTP-12593</p> - </item> - <item> - <p><c>is_builtin(erlang, apply, 3)</c> will now return - <c>true</c>.</p> - <p> - Own Id: OTP-13034</p> - </item> - <item> - <p> - Fix <c>enif_get_list_length</c> to return false if list - is improper or have length larger than <c>UINT_MAX</c> - (did return true and an incorrect length value).</p> - <p> - Own Id: OTP-13288 Aux Id: PR913 </p> - </item> - <item> - <p> - Cleanup hipe signal handling code for x86 and make it - more portable.</p> - <p> - Own Id: OTP-13341 Aux Id: PR951 </p> - </item> - <item> - <p> - Use fsync instead of fdatasync on Mac OSX.</p> - <p> - Own Id: OTP-13411</p> - </item> - <item> - <p> - Make sure to create a crash dump when running out of - memory. This was accidentally removed in the erts-7.3 - release.</p> - <p> - Own Id: OTP-13419</p> - </item> - <item> - <p> - A bug has been fixed where if erlang was started +B on a - unix platform it would be killed by a SIGUSR2 signal when - creating a crash dump.</p> - <p> - Own Id: OTP-13425</p> - </item> - <item> - <p> - Fix race between <c>process_flag(trap_exit,true)</c> and - a received exit signal.</p> - <p> - A process could terminate due to exit signal even though - <c>process_flag(trap_exit,true)</c> had returned. A very - specific timing between call to <c>process_flag/2</c> and - exit signal from another scheduler was required for this - to happen.</p> - <p> - Own Id: OTP-13452</p> - </item> - <item> - <p>Don't search for non-existing Map keys twice</p> - <p>For <c>maps:get/2,3</c> and <c>maps:find/2</c>, - searching for an immediate key, e.g. an atom, in a small - map, the search was performed twice if the key did not - exist.</p> - <p> - Own Id: OTP-13459</p> - </item> - <item> - <p> - When a abnormally large distribution message is about to - be sent, the VM has been changed to create a crash dump - instead of a core dump.</p> - <p> - Own Id: OTP-13474</p> - </item> - <item> - <p> - Fix <c>erlang:process_info/2</c> type specification</p> - <p> - Own Id: OTP-13485 Aux Id: ERL-123 </p> - </item> - <item> - <p> - Fix bug in <c>open_port/2</c> with option <c>{args, - List}</c>. A vm crash could be caused by an improper - <c>List</c>.</p> - <p> - Own Id: OTP-13489 Aux Id: ERL-127 </p> - </item> - <item> - <p> - Don't crash on terminating processes with - <c>erlang:system_profile/1,2</c></p> - <p> - Own Id: OTP-13494 Aux Id: ERL-126 </p> - </item> - <item> - <p> - Fixed bugs where the reduction counter was not handled - correct.</p> - <p> - Own Id: OTP-13512</p> - </item> - <item> - <p> - Fixed typo in description of the <c>EPMD_DUMP_REQ</c> - response.</p> - <p> - Own Id: OTP-13517</p> - </item> - <item> - <p> - Fixed a bug where a process flagged as sensitive would - sometimes record its save_calls when it shouldn't.</p> - <p> - Own Id: OTP-13540</p> - </item> - <item> - <p> - Update configure scripts to not use hardcoded path for - /bin/pwd and /bin/rm.</p> - <p> - Own Id: OTP-13562</p> - </item> - <item> - <p> - When passing a larger binary than the outputv callback of - a linked-in driver can handle in one io vector slot, the - binary is now split into multiple slots in the io vector. - This change only effects system where the max size of an - io vector slot is smaller then the word size of the - system (e.g. Windows).</p> - <p> - This change means that it is now possible on Windows to - send binaries that are larger than 4GB to port_comnmand, - which is what is used for file:write, gen_tcp:send etc.</p> - <p> - Own Id: OTP-13628</p> - </item> - </list> - </section> - - - <section><title>Improvements and New Features</title> - <list> - <item> - <p> - The tracing support has been extended to allow a <seealso - marker="erl_tracer">tracer module</seealso> to be the - trace event handler instead of a process or port. The - <seealso marker="erl_tracer">tracer module</seealso> - makes it possible for trace tools to filter or manipulate - trace event data without the trace event first haing to - be copied from the traced process or port.</p> - <p> - With the introduction of this feature, - <c>erlang:trace(all|existing, _, _)</c> now also returns - the tracer process as part of the number of processes on - which tracing is enabled. The is incompatible with the - previous releases.</p> - <p> - *** POTENTIAL INCOMPATIBILITY ***</p> - <p> - Own Id: OTP-10267</p> - </item> - <item> - <p> - Introduce LTTng tracing of Erlang Runtime System</p> - <p> - For LTTng to be enabled OTP needs to be built with - configure option <c>--with-dynamic-trace=lttng</c>.</p> - <p> - This feature introduces tracepoints for schedulers, - drivers, memory carriers, memory and async thread pool.</p> - <p> For a list of all tracepoints, see <seealso - marker="runtime_tools:LTTng">Runtime Tools User's - Guide</seealso> .</p> - <p> - Own Id: OTP-10282</p> - </item> - <item> - <p> - Add microstate accounting</p> - <p> - Microstate accounting is a way to track which state the - different threads within ERTS are in. The main usage area - is to pin point performance bottlenecks by checking which - states the threads are in and then from there figuring - out why and where to optimize.</p> - <p> - Since checking whether microstate accounting is on or off - is relatively expensive only a few of the states are - enabled by default and more states can be enabled through - configure.</p> - <p> - There is a convinence module called msacc that has been - added to runtime_tools that can assist in gathering and - interpreting the data from Microstate accounting.</p> - <p> - For more information see <seealso - marker="erts:erlang#statistics_microstate_accounting">erlang:statistics(microstate_accounting, - _)</seealso> and the <seealso - marker="runtime_tools:msacc">msacc</seealso> module in - runtime_tools.</p> - <p> - Own Id: OTP-12345</p> - </item> - <item> - <p> - The port of Erlang/OTP to the realtime operating system - OSE has been removed.</p> - <p> - Own Id: OTP-12573</p> - </item> - <item> - <p> - Sharing preserved copy for messages and exit signals</p> - <p> - Enable sharing preserved copy with configure option - <c>--enable-sharing-preserving</c>. This will preserve - sharing, within the process, when communication with - other processes in the Erlang node. There is a trade-off, - the copy is more costly but this cost can be reclaimed if - there is a lot of sharing in the message. With this - feature enabled literals will not be copied in a send - except during a purge phase of the module where the - literals are located. This feature is considered - experimental in 19.0.</p> - <p> - Own Id: OTP-12590 Aux Id: OTP-10251 </p> - </item> - <item> - <p> - Halfword BEAM has been removed.</p> - <p> - Own Id: OTP-12883</p> - </item> - <item> - <p> - Added <seealso - marker="kernel:os#perf_counter/1">os:perf_counter/1</seealso>.</p> - <p> - The perf_counter is a very very cheap and high resolution - timer that can be used to timestamp system events. It - does not have monoticity guarantees, but should on most - OS's expose a monotonous time.</p> - <p> - Own Id: OTP-12908</p> - </item> - <item> - <p> - Support for a fragmented young heap generation. That is, - the young heap generation can consist of multiple non - continuous memory areas. The main reason for this change - is to avoid extra copying of messages that could not be - allocated directly on the receivers heap.</p> - <p> - Own Id: OTP-13047</p> - </item> - <item> - <p> - Erlang linked-in driver can now force the call to - open_port to block until a call to erl_drv_init_ack is - made inside the driver. This is useful when you want to - do some asynchronous initialization, for example getting - configuration from a pipe, and you want the initial - open_port call to fail if the configuration is incomplete - or wrong. See the erl_driver documentation for more - details on the API.</p> - <p> - Own Id: OTP-13086</p> - </item> - <item> - <p> - Erlang linked-in drivers can now set their own pid's as - seen in <c>erlang:port_info/1</c> by using the - <c>erl_drv_set_pid</c> function. For more details see the - erl_driver documentation.</p> - <p> - Own Id: OTP-13087</p> - </item> - <item> - <p> - The functionality behind <c>erlang:open_port/2</c> when - called with spawn or spawn_executable has been redone so - that the forking of the new program is done in a separate - process called erl_child_setup. This allows for a much - more robust implementation that uses less memory and does - not block the entire emulator if the program to be - started is on an un-accessible NFS. Benchmarks have shown - this approach to be about 3-5 times as fast as the old - approach where the fork/vfork was done by erts. This is a - pure stability and performance fix, however some error - messages may have changed, which is why it is marked as a - backwards incompatible change.</p> - <p> - *** POTENTIAL INCOMPATIBILITY ***</p> - <p> - Own Id: OTP-13088</p> - </item> - <item> - <p>Improved yielding strategy in the implementation of - the following native functions:</p> <list> - <item><c>erlang:binary_to_list/1</c></item> - <item><c>erlang:binary_to_list/3</c></item> - <item><c>erlang:bitstring_to_list/1</c></item> - <item><c>erlang:list_to_binary/1</c></item> - <item><c>erlang:iolist_to_binary/1</c></item> - <item><c>erlang:list_to_bitstring/1</c></item> - <item><c>binary:list_to_bin/1</c></item> </list> <p>This - in order to improve performance of these functions.</p> - <p> - Own Id: OTP-13096</p> - </item> - <item> - <p> - All garbage collections of processes now bump reductions. - Also the amount of reductions bumped when garbage - collecting has been adjusted. It now better corresponds - to the amount of work performed. This in order to improve - the real time characteristics of the system.</p> - <p> - Own Id: OTP-13097</p> - </item> - <item> - <p>New functions that can load multiple functions at once - have been added to the '<c>code</c>' module. The - functions are <c>code:atomic_load/1</c>, - <c>code:prepare_loading/1</c>, - <c>code:finish_loading/1</c>, and - <c>code:ensure_modules_loaded/1</c>.</p> - <p> - Own Id: OTP-13111</p> - </item> - <item> - <p>The <c>-boot_var</c> option for <c>erl</c> now only - supports a single key and single value (as documented). - The option used to allow multiple key/value pairs, but - that behavior was undocumented.</p> - <p>The function <c>erl_prim_loader:start/3</c> has been - removed. Its documentation has also been removed.</p> - <p>The undocumented and unsupported function - <c>erl_prim_loader:get_files/2</c> has been removed.</p> - <p> - Own Id: OTP-13112</p> - </item> - <item> - <p> - Low level BIF <c>erlang:purge_module/1</c> is made more - robust against incorrect use. Lingering processes that - still refer the old code are now killed before the module - is purged to prevent fatal VM behavior.</p> - <p> - Own Id: OTP-13122</p> - </item> - <item> - <p> - Improved dirty scheduler implementation. For more - information see the <seealso - marker="erl_nif#dirty_nifs">NIF documentation</seealso>.</p> - <p> - Note that support for determining whether dirty NIF - support exist or not at compile time using the C - preprocessor macro <c>ERL_NIF_DIRTY_SCHEDULER_SUPPORT</c> - has been removed.</p> - <p> - Own Id: OTP-13123</p> - </item> - <item> - <p> - Various optimizations done to process dictionary access.</p> - <p> - Own Id: OTP-13167</p> - </item> - <item> - <p> - Added max_heap_size process flag. See erlang:process_flag - for more details.</p> - <p> - Own Id: OTP-13174</p> - </item> - <item> - <p> - Allow dynamic drivers and NIF libraries to be built with - gcc option <c>-fvisibility=hidden</c> for faster loading - and more optimized code.</p> - <p> - Own Id: OTP-13227</p> - </item> - <item> - <p> - Add <c>erlang:process_info(Pid, - garbage_collection_info)</c> which returns extended - garbage_collection information. For more details see the - documentation.</p> - <p> - Own Id: OTP-13265</p> - </item> - <item> - <p> - The functions <c>erlang:list_to_integer/1</c> and - <c>string:to_integer/1</c> have been optimized for large - inputs.</p> - <p> - Own Id: OTP-13293</p> - </item> - <item> - <p> - Improved memory allocation strategy for hipe native code - on x86_64 (amd64) architectures by reserving enough low - virtual address space needed for the HiPE/AMD64 small - code model. The default virtual address area for hipe - code is set to 512Mb, but can be changed with emulator - flag <c>+MXscs</c>.</p> - <p> - Own Id: OTP-13359</p> - </item> - <item> - <p> - Introduction of configurable management of data referred - to by the message queue of a process. Each process can be - configured individually.</p> - <p> - It is now possible to configure the message queue of a - process, so that all data referred by it will be kept - outside of the heap, and by this prevent this data from - being part of garbage collections.</p> - <p> - For more information see the documentation of <seealso - marker="erlang#process_flag_message_queue_data"><c>process_flag(message_queue_data, - MQD)</c></seealso>.</p> - <p> - Own Id: OTP-13366 Aux Id: OTP-13047 </p> - </item> - <item> - <p> - Processes now yield when scanning large message queues - and not finding a matching message. This in order to - improve real time characteristics.</p> - <p> - Own Id: OTP-13401</p> - </item> - <item> - <p> - Optimized an erts internal function that is used to - traverse erlang terms. The internal function was mainly - used by term_to_binary and comparison of terms. - Benchmarks have shown up to a 10% performance increase in - those functions after the optimization.</p> - <p> - Own Id: OTP-13440</p> - </item> - <item> - <p> - Add the following NIF API functions:</p> - <p> - <list> <item><seealso - marker="erl_nif#enif_cpu_time"><c>enif_cpu_time</c></seealso></item> - <item><seealso - marker="erl_nif#enif_now_time"><c>enif_now_time</c></seealso></item> - <item><seealso - marker="erl_nif#enif_make_unique_integer"><c>enif_make_unique_integer</c></seealso></item> - <item><seealso - marker="erl_nif#enif_is_process_alive"><c>enif_is_process_alive</c></seealso></item> - <item><seealso - marker="erl_nif#enif_is_port_alive"><c>enif_is_port_alive</c></seealso></item> - <item><seealso - marker="erl_nif#enif_term_to_binary"><c>enif_term_to_binary</c></seealso></item> - <item><seealso - marker="erl_nif#enif_binary_to_term"><c>enif_binary_to_term</c></seealso></item> - <item><seealso - marker="erl_nif#enif_port_command"><c>enif_port_command</c></seealso></item> - </list></p> - <p> - for details of what each function does, see the erl_nif - documentation.</p> - <p> - Own Id: OTP-13442</p> - </item> - <item> - <p> - Optimize <c>'++'</c> operator and <c>lists:append/2</c> - by using a single pass to build a new list while checking - for properness.</p> - <p> - Own Id: OTP-13487</p> - </item> - <item> - <p> - Handle terms (pids,ports and refs) from nodes with a - 'creation' value larger than 3. This is a preparation of - the distribution protocol to allow OTP 19 nodes to - correctly communicate with future nodes (20 or higher). - The 'creation' value differentiates different - incarnations of the same node (name).</p> - <p> - Own Id: OTP-13488</p> - </item> - <item> - <p> - Don't send unasked for systemd notifications in epmd</p> - <p> - Own Id: OTP-13493 Aux Id: PR-999 </p> - </item> - <item> - <p> - The enif_send API has been extended to allow NULL to be - used as the message environment. When used this way, a - message environent is implicitly created and the given - term is copied into that environment before sending. This - can be an optimization if many small messages are being - sent by the nif.</p> - <p> - Own Id: OTP-13495</p> - </item> - <item> - <p> - The tracing support has been extended to allow tracing on - ports. Ports can be traced on using the 'ports', 'send' - and 'receive' trace flags.</p> - <p> - The first argument of <seealso - marker="erts:erlang#trace/3">erlang:trace/3</seealso> has - been extended so that <c>'all'</c>, <c>'existing'</c> and - <c>'new'</c> now include both processes and ports. New - <c>Tracee</c> variants, <c>'all_processes'</c>, - <c>'all_ports'</c>, <c>'existing_processes'</c> etc have - been added to specify only processes or ports.</p> - <p> - *** POTENTIAL INCOMPATIBILITY ***</p> - <p> - Own Id: OTP-13496</p> - </item> - <item> - <p> - When the <c>'procs'</c> trace flag is enabled, a - <c>'spawned'</c> trace event is now also generated by a - newly created process. The previous event <c>'spawn'</c> - remains, but as it is generated by the process that did - the spawn, it is not guaranteed that it is ordered with - other trace events from the newly spawned process. So - when tracking the lifetime of a process this new event - should be used as the creation event.</p> - <p> - This new trace event is marked as an incompatabiliy - because tools that expect certain trace events when - enabling 'procs' will have to updated.</p> - <p> - *** POTENTIAL INCOMPATIBILITY ***</p> - <p> - Own Id: OTP-13497</p> - </item> - <item> - <p> - Add the <seealso - marker="erts:erlang#match_spec_test/3">erlang:match_spec_test/3</seealso> - function. The functions allows the testing of match - specifications for both tracing and ets tables. It can be - used to test that a match specification does the expected - filtering on specific data. It also returns more verbose - error reasons for incorrectly constructed match - specifications.</p> - <p> - Own Id: OTP-13501</p> - </item> - <item> - <p> - The erts internal tracing support has been changed to - have much less overhead and be more scalable.</p> - <p> - This rewrite does not break any backwards - incompatabilities, but it does change the ordering of - some trace messages when compared to previous releases. - It should be noted that this only applies to trace - messages sent to processes or ports, it does not apply to - the new tracer module. However in future releases they - may also be effected by this.</p> - <p> - Trace messages are only guaranteed to be ordered from one - traced process or port. In previous releases this was not - visible as a <c>'send'</c> trace message would always - arrive before the corresponding <c>'receive'</c> trace - message that is no longer always the case. This also - means that timestamped trace messages may seem to arrive - out of order as the timestamp is taken when the event is - triggered and not when it is put in the queue of the - tracer.</p> - <p> - Own Id: OTP-13503</p> - </item> - <item> - <p> - Add possibility to filter <c>send</c> and <c>receive</c> - trace with match specifications.</p> - <p> - Own Id: OTP-13507</p> - </item> - <item> - <p> - Add <c>maps:update_with/3,4</c> and <c>maps:take/2</c></p> - <p> - Own Id: OTP-13522 Aux Id: PR-1025 </p> - </item> - <item> - <p> - Introduce LTTng tracing via Erlang tracing.</p> - <p> - For LTTng to be enabled OTP needs to be built with - configure option <c>--with-dynamic-trace=lttng</c>.</p> - <p>The dynamic trace module <c>dyntrace</c> is now - capable to be used as a LTTng sink for Erlang tracing. - For a list of all tracepoints, see <seealso - marker="runtime_tools:LTTng">Runtime Tools User's - Guide</seealso> .</p> - <p>This feature also introduces an incompatible change in - trace tags. The trace tags <c>gc_start</c> and - <c>gc_end</c> has been split into <c>gc_minor_start</c>, - <c>gc_minor_end</c> and <c>gc_major_start</c>, - <c>gc_major_end</c>.</p> - <p> - *** POTENTIAL INCOMPATIBILITY ***</p> - <p> - Own Id: OTP-13532</p> - </item> - <item> - <p> - Print heap pointers for garbing processes during - crashdump</p> - <p> - Own Id: OTP-13541 Aux Id: PR-1026 </p> - </item> - <item> - <p> - Changed and improved low level memory statistics returned - by <c>erlang:system_info/1</c>. The info for - <c>erts_mmap</c> has been moved from <c>mseg_alloc</c> to - its own section returned by <c>{allocator, - erts_mmap}</c>.</p> - <p> - Own Id: OTP-13560</p> - </item> - <item> - <p> - Add enif_snprintf to the NIF API</p> - <p> - The fucntion <c>enif_snprintf</c> is similar to - <c>snprintf</c> call but can handle formating of Erlang - terms via <c>%T</c> format specifier.</p> - <p> - Own Id: OTP-13580</p> - </item> - <item> - <p>The warning in the documentation for - <c>erlang:raise/3</c> has been removed. It is now - officially perfectly fine to use raise/3 in production - code. (Thanks to Per Hedeland.)</p> - <p> - Own Id: OTP-13599</p> - </item> - <item> - <p> - Add <c>-start_epmd</c> command line option, this lets you - disable automatic starting of epmd when starting a - distributed node.</p> - <p> - Add <c>-epmd_module</c> command line option, this lets - you specify a module to register and lookup node names - in. The default module is <c>erl_epmd</c>.</p> - <p> - Own Id: OTP-13627</p> - </item> - <item> - <p> - <c>erlang:halt</c> now truncates strings longer than 200 - characters instead of failing with <c>badarg</c>.</p> - <p> - Own Id: OTP-13630</p> - </item> - </list> - </section> - -</section> - <section><title>Erts 7.3.1</title> <section><title>Fixed Bugs and Malfunctions</title> |