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diff --git a/erts/doc/src/notes.xml b/erts/doc/src/notes.xml index a4867adf22..058c1662e8 100644 --- a/erts/doc/src/notes.xml +++ b/erts/doc/src/notes.xml @@ -30,6 +30,485 @@ </header> <p>This document describes the changes made to the ERTS application.</p> +<section><title>Erts 5.8</title> + + <section><title>Fixed Bugs and Malfunctions</title> + <list> + <item> + <p> + Driver threads, such as async threads, using <seealso + marker="erl_driver#ErlDrvPDL">port data locks</seealso> + peeked at the port status field without proper locking + when looking up the driver queue.</p> + <p> + Own Id: OTP-8475</p> + </item> + <item> + <p> + The use of <c>mmap()</c> was unnecessarily disabled when + cross compiling.</p> + <p> + The <c>configure</c> arguments <c>--with-ssl</c>, and + <c>--with-odbc</c> refused to accept libraries outside of + <c>$erl_xcomp_sysroot</c> when cross compiling for no + good reason.</p> + <p> + The <c>configure</c> argument <c>--with-odbc</c> didn't + handle the value <c>yes</c> correct.</p> + <p> + The <c>configure</c> arguments <c>--with-odbc</c>, and + <c>--without-odbc</c> have also been added to the + configure help.</p> + <p> + (Thanks to Steve Vinoski for reporting these issues)</p> + <p> + Own Id: OTP-8484</p> + </item> + <item> + <p> + A call to the BIF <c>unregister(RegName)</c> when a port + had the name <c>RegName</c> registered in the runtime + system without SMP support caused a runtime system crash. + (Thanks to Per Hedeland for the bugfix and test case.)</p> + <p> + Own Id: OTP-8487</p> + </item> + <item> + <p> + The runtime system crashed if fewer logical processors + were found than reported by <c>sysconf( + SC_NPROCESSORS_CONF)</c>.</p> + <p> + Own Id: OTP-8549</p> + </item> + <item> + <p> + Fix memory management bug causing crash of non-SMP + emulator with async threads enabled. The bug did first + appear in R13B03.</p> + <p> + Own Id: OTP-8591 Aux Id: seq11554 </p> + </item> + <item> + <p> + Port locks could be prematurely destroyed.</p> + <p> + Own Id: OTP-8612</p> + </item> + <item> + <p>The <c>empd</c> program could loop and consume 100% + CPU time if an unexpected error ocurred in + <c>listen()</c> or <c>accept()</c>. Now <c>epmd</c> will + terminate if a non-recoverable error occurs. (Thanks to + Michael Santos.)</p> + <p> + Own Id: OTP-8618</p> + </item> + <item> + <p> + When kernel poll has been enabled, a livelock could in + rare circumstances occur. Problem reported by Chetan + Ahuja, fix by Mikael Pettersson.</p> + <p> + Own Id: OTP-8632</p> + </item> + <item> + <p> + Windows: Closing port of program that stalled without + reading all data could deadlock scheduler thread.</p> + <p> + Own Id: OTP-8641</p> + </item> + <item> + <p> + On some combination of Montavista Linux on Cavium Octeon + processors, some socket-related system calls returned + other numbers than -1 for errors. This caused a core dump + in inet_drv.c. Now the code works around this problem.</p> + <p> + Own Id: OTP-8654</p> + </item> + <item> + <p> + Missing memory barriers in <c>erts_poll()</c> could cause + the runtime system to hang indefinitely.</p> + <p> + Own Id: OTP-8658</p> + </item> + <item> + <p> + <c>ethr_rwmutex_tryrlock()</c> acquired and refused to + acquire a lock with inverted logic. The lock was however + never acquired in a thread unsafe manner. (Thanks to JR + Zhang for noting this issue)</p> + <p> + Own Id: OTP-8662</p> + </item> + <item> + <p> + Extreme combinations of register/unregister in a highly + parallell SMP application could crash the VM. The error + is corrected.</p> + <p> + Own Id: OTP-8663</p> + </item> + <item> + <p> + On Windows, files are now opened with FILE_SHARE_DELETE + to get closer to Unix semantics.</p> + <p> + Own Id: OTP-8667</p> + </item> + <item> + <p> + <c>erlang:system_info(multi_scheduling)</c> sometimes + erroneously returned <c>enabled</c> when it should have + returned <c>blocked</c>.</p> + <p> + Own Id: OTP-8675</p> + </item> + <item> + <p> + Fix bug causing <c>erlang:decode_packet</c> and + <c>enif_make_string</c> to generate faulty strings with + negative character values for ascii values larger than + 127. (Thanks to Paul Guyot)</p> + <p> + Own Id: OTP-8685</p> + </item> + <item> + <p> + <c>open_port/2</c> with the <c>spawn</c> and + <c>spawn_executable</c> options can include an + <c>{env,Env}</c> option. In some cases unsetting + variables would not work on Unix (typically if more + variables were unset than were actually present in the + environment).</p> + <p> + Own Id: OTP-8701</p> + </item> + </list> + </section> + + + <section><title>Improvements and New Features</title> + <list> + <item> + <p> + The grammar for match specifications in ERTS users guide + only described the tracing dialect of match + specifications. An informal grammar for the ETS dialect + is added.</p> + <p> + Own Id: OTP-8086 Aux Id: seq11333 </p> + </item> + <item> + <p> + The module binary from EEP31 (and EEP9) is implemented.</p> + <p> + Own Id: OTP-8217</p> + </item> + <item> + <p> + New NIF API function <c>enif_make_new_binary</c></p> + <p> + Own Id: OTP-8474</p> + </item> + <item> + <p> + The guard BIF <c>is_boolean/1</c> (introduced in R10B) + has now been included in the lists of BIFs allowed in + guards in the Reference Manual.</p> + <p> + Own Id: OTP-8477</p> + </item> + <item> + <p> + Added function <c>zip:foldl/3</c> to iterate over zip + archives.</p> + <p> + Added functions to create and extract escripts. See + <c>escript:create/2</c> and <c>escript:extract/2</c>.</p> + <p> + The undocumented function <c>escript:foldl/3</c> has been + removed. The same functionality can be achieved with the + more flexible functions <c>escript:extract/2</c> and + <c>zip:foldl/3</c>.</p> + <p> + Record fields has been annotated with type info. Source + files as been adapted to fit within 80 chars and trailing + whitespace has been removed.</p> + <p> + Own Id: OTP-8521</p> + </item> + <item> + <p>A regular expression with many levels of parenthesis + could cause a buffer overflow. That has been corrected. + (Thanks to Michael Santos.)</p> + <p> + Own Id: OTP-8539</p> + </item> + <item> + <p> + <c>erlang:decode_packet(httph_bin,..)</c> could return + corrupt header strings or even crash the VM. This has + been fixed. It only happened on 32-bit VM if the header + name was unknown and between 16 and 20 characters long. + Sockets with simular <c>packet</c> option did not suffer + from this bug.</p> + <p> + Own Id: OTP-8548</p> + </item> + <item> + <p>New NIF features:</p> <list><item> Send messages from + a NIF, or from thread created by NIF, to any local + process (<c>enif_send</c>) </item><item> Store terms + between NIF calls (<c>enif_alloc_env</c>, + <c>enif_make_copy</c>) </item><item> Create binary terms + with user defined memory management + (<c>enif_make_resource_binary</c>) </item></list> <p>And + some incompatible changes made to the API. For more + information see the warning text in <seealso + marker="erl_nif">erl_nif(3)</seealso>.</p> + <p> + *** POTENTIAL INCOMPATIBILITY ***</p> + <p> + Own Id: OTP-8555</p> + </item> + <item> + <p>If the '<c>fop</c>' program (needed for building PDF + files) cannot not be found, it is now possible to build + the HTML and man pages anyway (there will also be dummy + PDF files with no real content created). (Thanks to + Tuncer Ayaz.)</p> + <p> + Own Id: OTP-8559</p> + </item> + <item> + <p>When defining macros the closing right parenthesis + before the dot is now mandatory.</p> + <p> + *** POTENTIAL INCOMPATIBILITY ***</p> + <p> + Own Id: OTP-8562</p> + </item> + <item> + <p>Local and imported functions now override the + auto-imported BIFs when the names clash. The pre R14 + behaviour was that auto-imported BIFs would override + local functions. To avoid that old programs change + behaviour, the following will generate an error:</p> + <list><item><p>Doing a call without explicit module name + to a local function having a name clashing with the name + of an auto-imported BIF that was present (and + auto-imported) before OTP R14A</p></item> + <item><p>Explicitly importing a function having a name + clashing with the name of an autoimported BIF that was + present (and autoimported) before OTP R14A</p></item> + <item><p>Using any form of the old compiler directive + <c>nowarn_bif_clash</c></p></item> </list> <p>If the BIF + was added or auto-imported in OTP R14A or later, + overriding it with an import or a local function will + only result in a warning,</p> <p>To resolve clashes, you + can either use the explicit module name <c>erlang</c> to + call the BIF, or you can remove the auto-import of that + specific BIF by using the new compiler directive + <c>-compile({no_auto_import,[F/A]}).</c>, which makes all + calls to the local or imported function without explicit + module name pass without warnings or errors.</p> <p>The + change makes it possible to add auto-imported BIFs + without breaking or silently changing old code in the + future. However some current code ingeniously utilizing + the old behaviour or the <c>nowarn_bif_clash</c> compiler + directive, might need changing to be accepted by the + compiler.</p> + <p> + *** POTENTIAL INCOMPATIBILITY ***</p> + <p> + Own Id: OTP-8579</p> + </item> + <item> + <p> + A bug in re that could cause certain regular expression + matches never to terminate is corrected. (Thanks to + Michael Santos and Gordon Guthrie.)</p> + <p> + Own Id: OTP-8589</p> + </item> + <item> + <p>The erlang:open_port spawn and spawn_executable + directives can include an <c>{env,Env}</c> directive to + set up environment variables for the spawned process. A + bug prevented applications from using <c>{env,Env}</c> to + set an environment variable whose value ended with a + '<c>=</c>' (equal sign) character; the trailing equal + sign was mistaken as an indication that an environment + variable was to be cleared from the environment of the + spawned process. (Thanks to Steve Vinoski.)</p> + <p> + Own Id: OTP-8614</p> + </item> + <item> + <p><c>receive</c> statements that can only read out a + newly created reference are now specially optimized so + that it will execute in constant time regardless of the + number of messages in the receive queue for the process. + That optimization will benefit calls to + <c>gen_server:call()</c>. (See <c>gen:do_call/4</c> for + an example of a receive statement that will be + optimized.)</p> + <p> + Own Id: OTP-8623</p> + </item> + <item> + <p> + The functions file:advise/4 and file:datasync/1 have been + added. (Thanks to Filipe David Manana.)</p> + <p> + Own Id: OTP-8637</p> + </item> + <item> + <p> + New NIF API functions: <c>enif_make_atom_len</c>, + <c>enif_make_existing_atom_len</c>, + <c>enif_make_string_len</c>, <c>enif_get_atom_length</c>, + <c>enif_get_list_length</c>, <c>enif_is_list</c>, + <c>enif_is_tuple</c> (by Tuncer Ayaz)</p> + <p> + Own Id: OTP-8640</p> + </item> + <item> + <p> + Support for using gcc's built-in functions for atomic + memory access has been added. This functionallity will be + used if available and no other native atomic + implementation in ERTS is available.</p> + <p> + Own Id: OTP-8659</p> + </item> + <item> + <p> + The number of spinlocks used when implementing atomic + fall-backs when no native atomic implementation is + available has been increased from 16 to 1024.</p> + <p> + Own Id: OTP-8660</p> + </item> + <item> + <p> + Writer preferred pthread read/write locks has been + enabled on Linux.</p> + <p> + Own Id: OTP-8661</p> + </item> + <item> + <p> + The runtime system will by default bind schedulers to + logical processors using the <c>default_bind</c> bind + type if the amount of schedulers are at least equal to + the amount of logical processors configured, binding of + schedulers is supported, and a CPU topology is available + at startup. </p> + <p> + <em>NOTE:</em> If the Erlang runtime system is the only + operating system process that binds threads to logical + processors, this improves the performance of the runtime + system. However, if other operating system processes (as + for example another Erlang runtime system) also bind + threads to logical processors, there might be a + performance penalty instead. If this is the case you, are + are advised to unbind the schedulers using the <seealso + marker="erl#+sbt">+sbtu</seealso> command line argument, + or by invoking <seealso + marker="erlang#system_flag_scheduler_bind_type">erlang:system_flag(scheduler_bind_type, + unbound)</seealso>.</p> + <p> + Own Id: OTP-8666</p> + </item> + <item> + <p> + The recently added BIFs erlang:min/2, erlang:max/2 and + erlang:port_command/3 are now auto-imported (as they were + originally intended to be). Due to the recent compiler + change (OTP-8579), the only impact on old code defining + it's own min/2, max/2 or port_command/3 functions will be + a warning, the local functions will still be used. The + warning can be removed by using + -compile({no_auto_import,[min/2,max/2,port_command/3]}). + in the source file.</p> + <p> + *** POTENTIAL INCOMPATIBILITY ***</p> + <p> + Own Id: OTP-8669 Aux Id: OTP-8579 </p> + </item> + <item> + <p> + There is a new option 'exclusive' to file:open/2 that + uses the OS O_EXCL flag where supported to open the file + in exclusive mode.</p> + <p> + Own Id: OTP-8670</p> + </item> + <item> + <p> + Now, binary_to_term/2 is auto-imported. This will cause a + compile warning if and only if a module has got a local + function with that name.</p> + <p> + *** POTENTIAL INCOMPATIBILITY ***</p> + <p> + Own Id: OTP-8671</p> + </item> + <item> + <p> + Alignment of scheduler data and run queues were adjusted.</p> + <p> + Own Id: OTP-8673</p> + </item> + <item> + <p>Call time breakpoint tracing</p> <list><item>Introduce + a <c>call_time</c> option to + <c>erlang:trace_pattern/3</c>.This option enables call + time breakpoint tracing on code that is executed by + processes with call tracing enabled. Call time tracing + stores the number of calls and the time spent of each + function with this trace pattern enabled. The information + can be retrieved with <c>erlang:trace_info/2</c></item> + <item>Add a scheduler array for BpData. To solve the + issue of multiple schedulers constantly updating the head + pointer to the bp data wheel, each scheduler now has its + own entrypoint to the wheel. This head pointer can be + updated without a locking being taken.</item></list> + <p>Teach call count tracing to use atomics</p> + <list><item>Call count previously used a global lock for + accessing and writing its counter in the breakpoint. This + is now changed to atomics instead.</item> <item>The + change will let call count tracing and cprof to scale + better when increasing the number of + schedulers.</item></list> + <p> + Own Id: OTP-8677</p> + </item> + <item> + <p><c>eprof</c> has been reimplemented with support in + the Erlang virtual machine and is now both faster (i.e. + slows down the code being measured less) and scales much + better. In measurements we saw speed-ups compared to the + old eprof ranging from 6 times (for sequential code that + only uses one scheduler/core) up to 84 times (for + parallel code that uses 8 cores).</p> + <p>Note: The API for the <c>eprof</c> has been cleaned up + and extended. See the documentation.</p> + <p> + *** POTENTIAL INCOMPATIBILITY ***</p> + <p> + Own Id: OTP-8706</p> + </item> + </list> + </section> + +</section> + <section><title>Erts 5.7.5</title> <section><title>Fixed Bugs and Malfunctions</title> |