From bb19e24a485e9ef43bcca3fbe9757da83f70c3a0 Mon Sep 17 00:00:00 2001 From: Erlang/OTP Date: Tue, 19 Jun 2018 08:24:54 +0200 Subject: Prepare release --- erts/doc/src/notes.xml | 936 +++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 936 insertions(+) (limited to 'erts/doc') diff --git a/erts/doc/src/notes.xml b/erts/doc/src/notes.xml index aaab52e424..ed0946d6ba 100644 --- a/erts/doc/src/notes.xml +++ b/erts/doc/src/notes.xml @@ -31,6 +31,942 @@

This document describes the changes made to the ERTS application.

+
Erts 10.0 + +
Fixed Bugs and Malfunctions + + +

+ The type specifications for file:posix/0 and + inet:posix/0 have been updated according to which + errors file and socket operations should be able to + return.

+

+ Own Id: OTP-14019 Aux Id: ERL-550

+ + +

+ Fix error printout from run_erl and a bug that could + cause unintended fds to be leaked into the started + program.

+

+ Own Id: OTP-14537 Aux Id: PR1529

+ + +

File operations used to accept filenames + containing null characters (integer value zero). This + caused the name to be truncated and in some cases + arguments to primitive operations to be mixed up. + Filenames containing null characters inside the filename + are now rejected and will cause primitive file + operations to fail.

Also environment variable + operations used to accept names and + values of + environment variables containing null characters (integer + value zero). This caused operations to silently produce + erroneous results. Environment variable names and values + containing null characters inside the name or value are + now rejected and will cause environment variable + operations to fail.

Primitive environment + variable operations also used to accept the $= + character in environment variable names causing various + problems. $= characters in environment variable + names are now also rejected.

Also + os:cmd/1 now + reject null characters inside its command. +

erlang:open_port/2 + will also reject null characters inside the port name + from now on.

+

+ *** POTENTIAL INCOMPATIBILITY ***

+

+ Own Id: OTP-14543 Aux Id: ERL-370

+ + +

+ Fix bugs related to the bookkeeping of microstate + accounting states.

+

+ Own Id: OTP-14652

+ + +

os:putenv and os:getenv no longer access + the process environment directly and instead work on a + thread-safe emulation. The only observable difference is + that it's not kept in sync with libc + getenv(3) / putenv(3), so those who relied + on that behavior in drivers or NIFs will need to add + manual synchronization.

On Windows this means that + you can no longer resolve DLL dependencies by modifying + the PATH just before loading the driver/NIF. To + make this less of a problem, the emulator now adds the + target DLL's folder to the DLL search path.

+

+ *** POTENTIAL INCOMPATIBILITY ***

+

+ Own Id: OTP-14666

+ + +

Corrected erlang:is_builtin(erlang, M, F) to + return true for apply/2 and + yield/0.

+

+ Own Id: OTP-14713 Aux Id: ERL-500

+ + +

Fixed a bug where the PATH environment variable wasn't + updated correctly on a release downgrade, effectively + keeping the PATH of the new release.

+

+ Own Id: OTP-14719

+ + +

A receive optimization that avoids scanning the entire + message queue when receiving a message containing a + freshly created reference could in rare circumstances + (involving recursive calls to the functions that does the + receive) cause the receive to hang. This has been + corrected.

+

+ Own Id: OTP-14782 Aux Id: ERL-511

+ + +

+ Fix building of Erlang/OTP on platforms which have small + data area with short addressing. For example the + PowerPC/RTEMS platform.

+

+ Own Id: OTP-14909 Aux Id: PR-1692

+ + +

Fixed a crash when enif_make_binary is called + with a binary produced by enif_inspect_binary in a + different environment.

+

+ Own Id: OTP-14931

+ + +

Fixed a crash when enif_make_binary is called + more than once with a binary that had previously been + added to an enif_ioq.

+

+ Own Id: OTP-14932

+ + +

+ The erl_child_setup program now ignores SIGTERM signals.

+

+ Own Id: OTP-14943 Aux Id: ERL-576

+ + +

+ Force 64-bit alignment on pre-allocators on architectures + which needs it.

+

+ Own Id: OTP-14977

+ + +

+ Fixed a bug where dirty scheduler picked up non-dirty + work.

+

+ Own Id: OTP-14978

+ + +

+ Calls to gen_tcp:send/2 on closed sockets now + returns {error, closed} instead of + {error,enotconn}.

+

+ Own Id: OTP-15001

+ + +

+ erlang:monotonic_time/1 failed with badarg + when passing the perf_counter time unit as + argument.

+

+ Own Id: OTP-15008

+ + +

+ Fix bug where rapid init:restart() calls would + sometimes crash because a code load request leaked in + between the restarts.

+

+ Own Id: OTP-15013

+ + +

+ Improve float_to_list(F, [{decimals,D}]) to closer + conform with io_lib:format("~.*f", [D,F]).

+

+ There are however, still cases when float_to_list + does not produce the exact same result as + io_lib:format, especially for large values + F and/or many decimals D.

+

+ Own Id: OTP-15015 Aux Id: OTP-14890

+ + +

Fixed a deadlock that would occur on certain + allocators when a reallocation failed with +ramv + enabled.

+

+ Own Id: OTP-15024

+ + +

+ Fix bug that made it impossible to use an erl_tracer as + the seq_trace trace receiver.

+

+ Own Id: OTP-15029

+ + +

+ Fix bug where a large (> 1 GB) emulator generated error + logger message would cause the emulator to crash.

+

+ Own Id: OTP-15032

+ + +

The emulator will no longer crash when reading the + file information of an ordinary file that has an NTFS + reparse point, such as files stored in a OneDrive-mapped + folder.

+

+ Own Id: OTP-15062 Aux Id: ERL-615

+ + +

+ Fixed bug in enif_binary_to_term which could cause + memory corruption for immediate terms (atoms, small + integers, pids, ports, empty lists).

+

+ Own Id: OTP-15080

+ + +

+ Fixed bug in erlang:system_profile/2 that could + cause superfluous {profile,_,active,_,_} messages + for terminating processes.

+

+ Own Id: OTP-15085

+ + +

+ On OSs with per thread CPU time support, change + cpu_timestamp in erlang:trace/3 to use + it instead of per process CPU time. This makes this + option useable on such OSs when running multiple + schedulers.

+

+ Own Id: OTP-15090

+ + +

+ Fix segfault in abort_signal_task which could happen if a + port terminated while there were outstanding port tasks + that were not signals, for example a + ready_input/ready_output event.

+

+ Own Id: OTP-15108 Aux Id: ERL-621

+ + +

+ Fixed bug in ets that could cause VM crash if + process A terminates after fixating a table and process B + deletes the table at "the same time". The table fixation + could be done with ets:safe_fixtable or if process + A terminates in the middle of a long running + select or match call.

+

+ Own Id: OTP-15109

+ + +

Owner and group changes through + file:write_file_info, file:change_owner, + and file:change_group will no longer report + success on permission errors.

+

+ *** POTENTIAL INCOMPATIBILITY ***

+

+ Own Id: OTP-15118

+ + +

+ Fix a bug error reporting from escripts on windows where + the error message would get garbled.

+

+ Own Id: OTP-15119 Aux Id: PR-1826

+ + +

+ Fix segfault when a process is interally re-scheduled + while being traced for in out events. This bug was + introduced in erts-8.0 (OTP-19.0).

+

+ Own Id: OTP-15125

+ + +
+ + +
Improvements and New Features + + +

It is now possible to open device files and FIFOs with + file:open/2.

+

+ Own Id: OTP-11462

+ + +

+ The erlang:system_flag(scheduler_wall_time,Bool) + call is now reference counted and will be turned off if + the (last) process that started the performance + statistics dies. Thus it is no longer possible to start + the statistics with rpc:call(Node, erlang, + system_flag, [scheduler_wall_time, true]) since it + will be turned off directly afterwards when the rpc + process dies.

+

+ *** POTENTIAL INCOMPATIBILITY ***

+

+ Own Id: OTP-11694

+ + +

A new logging API is added to Erlang/OTP, see the + logger(3) manual + page, and section Logging in the + Kernel User's Guide.

+

Calls to error_logger are automatically + redirected to the new API, and legacy error logger event + handlers can still be used. It is, however, recommended + to use the Logger API directly when writing new code.

+

Notice the following potential incompatibilities:

+

Kernel configuration parameters + error_logger still works, but is overruled if the + default handler's output destination is configured with + Kernel configuration parameter logger.

In + general, parameters for configuring error logger are + overwritten by new parameters for configuring + Logger.

The concept of SASL error + logging is deprecated, meaning that by default the SASL + application does not affect which log events are + logged.

By default, supervisor reports and crash + reports are logged by the default Logger handler started + by Kernel, and end up at the same destination (terminal + or file) as other standard log event from Erlang/OTP.

+

Progress reports are not logged by default, but can be + enabled by setting the primary log level to info, for + example with the Kernel configuration parameter + logger_level.

To obtain backwards + compatibility with the SASL error logging functionality + from earlier releases, set Kernel configuration parameter + logger_sasl_compatible to true. This + prevents the default Logger handler from logging any + supervisor-, crash-, or progress reports. Instead, SASL + adds a separate Logger handler during application start, + which takes care of these log events. The SASL + configuration parameters sasl_error_logger and + sasl_errlog_type specify the destination (terminal + or file) and severity level to log for these + events.

 +

+ Since Logger is new in Erlang/OTP 21.0, we do reserve the + right to introduce changes to the Logger API and + functionality in patches following this release. These + changes might or might not be backwards compatible with + the initial version.

+

+ *** POTENTIAL INCOMPATIBILITY ***

+

+ Own Id: OTP-13295

+ + +

+ gen_sctp:connect_init/4 or rather connect in + inet_drv.c for SCTP has been fixed to not check + the write file descriptor for writeability after a + connect, since for SCTP (SOCK_SEQPACKET) that property + does not seem to be any kind of indicator for when a + connect has finished. This fixes connects that the OS + returned as "in progress" that was misinterpreted by + gen_sctp:connect_init as failed.

+

+ Own Id: OTP-13760 Aux Id: PR-1592

+ + +

The file driver has been rewritten as a NIF, + decreasing the latency of file operations. Notable + incompatibilities are:

The + use_threads option for file:sendfile/5 no + longer has any effect; we either use non-blocking + sendfile(2) or fall back to file:read + + gen_tcp:send.

The + file-specific DTrace probes have been removed. The same + effect can be achieved with normal tracing together with + the nif__entry/nif__return probes to track + scheduling.

 +

+ *** POTENTIAL INCOMPATIBILITY ***

+

+ Own Id: OTP-14256

+ + +

The I/O polling functionality of erts has been + re-written to better make use of the OSs polling + mechanisms. This change means that erts will now always + prefer to use a kernel-polling mechanism if possible. + Also all of the I/O polling has been moved to dedicated + threads instead of being placed in the scheduler + loops.

As a result of this, the erl options + +K and +secio have been removed. It is + still possible to disable kernel-poll, but it has to be + done at compile time through the configure option + --disable-kernel-poll.

The new erl + options +IOt + and +IOp can + be used to change how many IO poll threads and poll sets + that erts should use. See their respective documentation + for more details.

+

+ Own Id: OTP-14346

+ + +

Truly asynchronous auto-connect. Earlier, when + erlang:send was aimed toward an unconnected node, + the function would not return until the connection setup + had completed (or failed). Now the function returns + directly after the message has been enqueued and the + connection setup started.

+

The same applies to all distributed operations that + may trigger auto-connect, i.e. '!', send, + link, monitor, monitor_node, + exit/2 and group_leader.

+

The interface for all these functions are unchanged as + they do not return connection failures. The only + exception is erlang:monitor where a possible + incompatibility is introduced: An attempt to monitor + a process on a primitive node (such as erl_interface or + jinterface), where remote process monitoring is not + implemented, will no longer fail with badarg + exception. Instead a monitor will be created, but it will + only supervise the connection to the node.

+

+ *** POTENTIAL INCOMPATIBILITY ***

+

+ Own Id: OTP-14370

+ + +

Changed the default behaviour of .erlang + loading: .erlang is no longer loaded from the + current directory. c:erlangrc(PathList) can be + used to search and load an .erlang file from user + specified directories.

escript, + erlc, dialyzer and typer no longer + load an .erlang at all.

+

+ *** POTENTIAL INCOMPATIBILITY ***

+

+ Own Id: OTP-14439

+ + +

+ New functionality for implementation of alternative + carriers for the Erlang distribution has been introduced. + This mainly consists of support for usage of distribution + controller processes (previously only ports could be used + as distribution controllers). For more information see + ERTS + User's Guide ➜ How to implement an Alternative Carrier + for the Erlang Distribution ➜ Distribution + Module.

+

+ Own Id: OTP-14459

+ + +

+ Add support for the lcc compiler and in extension the + Elbrus 2000 platform.

+

+ Own Id: OTP-14492

+ + +

Support for "tuple calls" have been removed from the + run-time system. Tuple calls was an undocumented and + unsupported feature which allowed the module argument for + an apply operation to be a tuple: Var = dict:new(), + Var:size(). This "feature" frequently caused + confusion, especially when such call failed. The + stacktrace would point out functions that don't exist in + the source code.

+

For legacy code that need to use parameterized modules + or tuple calls for some other reason, there is a new + compiler option called tuple_calls. When this + option is given, the compiler will generate extra code + that emulates the old behavior for calls where the module + is a variable.

+

+ *** POTENTIAL INCOMPATIBILITY ***

+

+ Own Id: OTP-14497

+ + +

Creation of small maps with literal keys has been + optimized to be faster and potentially use less memory. + The keys are combined into a literal key tuple which is + put into the literal pool. The key tuple can be shared + between many instances of maps having the same keys.

+

+ Own Id: OTP-14502

+ + +

+ When an exception is thrown, include the arguments of the + call in the stacktrace for BIFs band, bor, + bsl, bsr, bxor, div, + rem and the operators +, -, * + and /.

+

+ *** POTENTIAL INCOMPATIBILITY ***

+

+ Own Id: OTP-14508

+ + +

+ The non-smp emulators have been removed. This means that + the configure options --disable-threads and + --enable-plain-emulator have been removed and + configure will now refuse to build Erlang/OTP on + platforms without thread support.

+

+ In order to achieve a similar setup as the non-smp + emulator, it is possible to start Erlang/OTP with the + +S 1 option.

+

+ *** POTENTIAL INCOMPATIBILITY ***

+

+ Own Id: OTP-14518

+ + +

Modules that use floating point constants compiled + with R15 or earlier will need to be re-compiled before + they can be loaded.

+

+ Own Id: OTP-14575

+ + +

+ Implementation of true asynchronous signaling between + processes in order to improve scalability. Signals + affected include exit, monitor, demonitor, monitor + triggered, link, unlink, and group leader.

+

+ Own Id: OTP-14589

+ + +

+ Added a PGO (profile guided optimization) pass to the + build step of erts. This can be disabled by passing + --disable-pgo to configure.

+

+ Own Id: OTP-14604

+ + +

+ Improved the performance of binary:split and + binary:match.

+

+ Own Id: OTP-14610 Aux Id: PR-1480

+ + +

+ It is not longer possible to disable dirty schedulers + when building erlang.

+

+ Own Id: OTP-14613

+ + +

Loaded BEAM code in a 64-bit system requires less + memory because of better packing of operands for + instructions.

+

These memory savings were achieved by major + improvements to the beam_makeops scripts used when + building the run time system and BEAM compiler. There is + also new for documentation for beam_makeops that + describes how new BEAM instructions and loader + transformations can be implemented. The documentation is + found in here in a source directory or git repository: + erts/emulator/internal_doc/beam_makeops.md. An online + version can be found here: + https://github.com/erlang/otp/blob/master/erts/emulator/internal_doc/beam_makeops.md

+

+ Own Id: OTP-14626

+ + +

file:read_file has been changed to read the + content of files that report a size of 0 even when data + can be read from them. An example of such a file is + /proc/cpuinfo on Linux.

+

+ Own Id: OTP-14637 Aux Id: ERL-327 PR-1524

+ + +

+ It is no longer possible to disable the temp_alloc + allocator. Disabling it caused serious performance + degradations and was never what was wanted.

+

+ Own Id: OTP-14651

+ + +

The reduction cost of sending messages is now + constant. It will no longer scale according to the length + of the receiving process' message queue.

+

+ Own Id: OTP-14667

+ + +

+ Improved loading of modules with -on_load + directive, to no longer block all schedulers when the + load operation is completed.

+

+ Own Id: OTP-14680

+ + +

+ On platforms with real-time signals available, SIGRTMIN+1 + is now used as the internal scheduler suspend signal + instead of SIGUSR2.

+

+ Own Id: OTP-14682

+ + +

When the value returned from a 'catch' + expression is ignored, no stacktrace will be built if an + exception is caught. That will save time and produce less + garbage. There are also some minor optimizations of + 'try/catch' both in the compiler and + run-time system.

+

+ Own Id: OTP-14683

+ + +

The guarantees and non-guarantees of + erlang:get_stacktrace/0 are now documented.

+

+ Own Id: OTP-14687

+ + +

There is a new syntax in 'try/catch' for + retrieving the stacktrace without calling + 'erlang:get_stacktrace/0'. See the reference + manual for a description of the new syntax. The + 'erlang:get_stacktrace/0' BIF is now + deprecated.

+

+ Own Id: OTP-14692

+ + +

+ New 'used' option for binary_to_term/2 that will + also return number of bytes actually read from the + binary. This enables easy access to any extra data in the + binary located directly after the returned term.

+

+ Own Id: OTP-14780

+ + +

+ Added more statistics for + erlang:system_info({allocator,A}) in the + mbcs_pool section.

+

+ Own Id: OTP-14795 Aux Id: ERL-88

+ + +

Added enif_ioq_peek_head to retrieve Erlang + terms from NIF IO queues without having to resort to + copying.

+

+ Own Id: OTP-14797

+ + +

There is a new option 'makedep_side_effect' for + the compiler and -MMD for 'erlc' that + generates dependencies and continues to compile as + normal.

+

+ Own Id: OTP-14830

+ + +

Added ets:whereis/1 for retrieving the table + identifier of a named table.

+

+ Own Id: OTP-14884

+ + +

seq_trace labels may now be any erlang + term.

+

+ Own Id: OTP-14899

+ + +

+ Optimized the common case of monitor followed by + send to the same local process. The monitor signal + is now delayed in order to be piggybacked with the sent + message and thereby only get one lock operation on the + message queue of the receiver. A delayed monitor signal + is flushed if no send has been done at the latest + when the process is scheduled out.

+

+ Own Id: OTP-14901

+ + +

+ Make hipe compiled code work on x86_64 (amd64) with OS + security feature PIE, where executable code can be loaded + into a random location. Old behavior, if hipe was + enabled, was to disable PIE build options for the VM.

+

+ Own Id: OTP-14903

+ + +

The number of driver async threads will now default to + 1 as the standard drivers do not use them anymore. Users + that changed this value to tweak the file driver should + replace +A with +SDio since it now uses + dirty IO schedulers instead of async threads.

+

+ *** POTENTIAL INCOMPATIBILITY ***

+

+ Own Id: OTP-14928

+ + +

+ Optimize == and /= for binaries with + different sizes to be constant in time instead of + proportional to the size of their common prefix.

+

+ Own Id: OTP-14934 Aux Id: PR-1708

+ + +

+ Refactorings making some internal process flags available + for other usage.

+

+ Own Id: OTP-14948

+ + +

+ Removed need for HiPE to allocate native executable + memory in low 2GB address space on x86_64. Command line + option +MXscs is thereby obsolete and ignored.

+

+ Own Id: OTP-14951

+ + +

Added enif_make_map_from_arrays for creating a + populated map, analogous to + enif_make_list_from_array.

+

+ Own Id: OTP-14954

+ + +

Added configuration switches for busy-wait and wake up + thresholds for dirty schedulers, and changing these + settings for normal schedulers will no longer affect + dirty schedulers.

Refer to the documentation for + details. The new switches are +sbwtdcpu, +sbwtdio, +swtdcpu, and +swtdio.

The + default busy wait threshold for dirty scheduler threads + has also been lowered to short.

+

+ Own Id: OTP-14959

+ + +

+ The list of "taints" now also includes dynamic loaded + drivers in addition to NIF libraries. Statically linked + drivers and NIF libraries that are part of erts are not + included. The "taints" are returned by + system_info(taints) and printed in the header of + erl_crash.dump files.

+

+ Own Id: OTP-14960

+ + +

Added instrument:allocations and + instrument:carriers for retrieving information + about memory utilization and fragmentation.

+

The old instrument interface has been removed, + as have the related options +Mim and + +Mis.

+

+ *** POTENTIAL INCOMPATIBILITY ***

+

+ Own Id: OTP-14961

+ + +

The process suspend functionality used by the erlang:suspend_process/2 + BIF has been reimplemented using the newly introduced + true asynchronous signaling between processes. This + mainly to reduce memory usage in the process control + block of all processes, but also in order to simplify the + implementation.

You can easily create + deadlocks if processes suspends each other (directly or + in circles). In ERTS versions prior to ERTS version 10.0, + the runtime system prevented such deadlocks, but this + prevention has now been removed due to performance + reasons.

Other ERTS internal + functionality that used the previous process suspend + functionality have also been reimplemented to use + asynchronous signaling instead.

+

+ *** POTENTIAL INCOMPATIBILITY ***

+

+ Own Id: OTP-14964 Aux Id: OTP-14589

+ + +

Added the nifs option to + ?MODULE:module_info/1 for listing a module's + installed NIF functions.

+

+ Own Id: OTP-14965

+ + +

+ New implementation of erlang:process_info/[1,2].

+

+ In the general case when inspecting another process, the + new implementation sends an asynchronous process-info + request signal to the other process and waits for the + result instead of locking the other process and reading + the result directly. In some special cases where no + conflicts occur, signal order wont be violated, and the + amount of data requested is guaranteed to be small, the + inspected process may be inspected directly.

+

+ Appropriate amount of reductions are now also bumped when + inspecting a process.

+

+ Own Id: OTP-14966

+ + +

+ Removed process start time from crash dump in order to + save memory in process control block.

+

+ Own Id: OTP-14975 Aux Id: PR-1597

+ + +

+ Optimize erlang:put/2 when updating existing key + with a new immediate value (atom, small integer, pid, + port).

+

+ Own Id: OTP-14976

+ + +

+ erlang:process_info/1 has been changed to no + longer include messages by default. Instead + erlang:process_info/2 should be used.

+

+ *** POTENTIAL INCOMPATIBILITY ***

+

+ Own Id: OTP-14986 Aux Id: PR-1745

+ + +

+ New erlang:system_info(ets_count) to get total + number of ets tables existing at the local node.

+

+ Own Id: OTP-14987

+ + +

+ New NIF functions: enif_mutex_name, + enif_cond_name, enif_rwlock_name, + enif_thread_name, enif_vfprintf, + enif_vsnprintf.

+

+ Own Id: OTP-14994

+ + +

When erlang:system_flag(backtrace_depth, 0) has + been called, all exceptions will now contain the entry + for one function (despite the zero). It used to + be that a hand-made stack backtrace passed to + erlang:raise/3 would be be truncated to an empty + list.

+

+ Own Id: OTP-15026

+ + +

+ Fixed bug for named ets tables which could cause + unexpected results from matchspec iteration functions + (ets:select* and ets:match*) if the table + was deleted and recreated with the same name during the + iteration. The iteration could incorrectly continue + through the recreated table. The expected correct + behavior is now for the iteration call to fail with a + badarg exception if the table is deleted before + the iteration has completed.

+

+ Own Id: OTP-15031

+ + +

Two new guards BIFs operating on maps have been added: + map_get/2 and is_map_key/2. They do the + same as maps:get/2 and maps:is_key/2, + respectively, except that they are allowed to be used in + guards.

+

+ Own Id: OTP-15037 Aux Id: PR-1784, PR-1802

+ + +

+ Release run-queue lock while cleaning up terminated dirty + process.

+

+ Own Id: OTP-15081

+ + +

The callback module passed as -epmd_module to + erl has been expanded to be able to do name and port + resolving.

Documentation has also been added in + the erl_epmd + reference manual and ERTS User's Guide How to Implement an Alternative + Service Discovery for Erlang Distribution.

+

+ Own Id: OTP-15086 Aux Id: PR-1694

+ + +
+ +
+
Erts 9.3.3
Fixed Bugs and Malfunctions -- cgit v1.2.3