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</header>
<p>This document describes the changes made to the ERTS application.</p>
+<section><title>Erts 5.9</title>
+
+ <section><title>Fixed Bugs and Malfunctions</title>
+ <list>
+ <item>
+ <p>
+ Honor option <c>packet_size</c> for http packet parsing
+ by both TCP socket and <c>erlang:decode_packet</c>. This
+ gives the ability to accept HTTP headers larger than the
+ default setting, but also avoid DoS attacks by accepting
+ lines only up to whatever length you wish to allow. For
+ consistency, packet type <c>line</c> also honor option
+ <c>packet_size</c>. (Thanks to Steve Vinoski)</p>
+ <p>
+ Own Id: OTP-9389</p>
+ </item>
+ <item>
+ <p> A few contracts in the <c>lists</c> module have been
+ corrected. </p>
+ <p>
+ Own Id: OTP-9616</p>
+ </item>
+ <item>
+ <p>
+ The Unicode noncharacter code points 16#FFFE and 16#FFFE
+ were not allowed to be encoded or decoded using the
+ <c>unicode</c> module or bit syntax. That was
+ inconsistent with the other noncharacters 16#FDD0 to
+ 16#FDEF that could be encoded/decoded. To resolve the
+ inconsistency, 16#FFFE and 16#FFFE can now be encoded and
+ decoded. (Thanks to Alisdair Sullivan.)</p>
+ <p>
+ *** POTENTIAL INCOMPATIBILITY ***</p>
+ <p>
+ Own Id: OTP-9624</p>
+ </item>
+ <item>
+ <p>
+ Make epp search directory of current file first when
+ including another file This completes a partial fix in
+ R11 that only worked for include_lib(). (Thanks to
+ Richard Carlsson)</p>
+ <p>
+ Own Id: OTP-9645</p>
+ </item>
+ <item>
+ <p>
+ Fixed memory leak in
+ <c>enif_inspect_io_list_as_binary</c> when applied on a
+ process independent environment.</p>
+ <p>
+ Own Id: OTP-9668</p>
+ </item>
+ <item>
+ <p>The number of beam catches allowed in code are no
+ longer statically defined and will grow according to its
+ need.</p>
+ <p>
+ Own Id: OTP-9692</p>
+ </item>
+ <item>
+ <p>
+ Add missing parenthesis in heart doc.</p>
+ <p>
+ Add missing spaces in the Reference Manual distributed
+ section.</p>
+ <p>
+ In the HTML version of the doc those spaces are necessary
+ to separate those words.</p>
+ <p>
+ Own Id: OTP-9693</p>
+ </item>
+ <item>
+ <p>
+ Fixes module erlang doc style: option description (Thanks
+ to Ricardo Catalinas Jim�nez)</p>
+ <p>
+ Own Id: OTP-9697</p>
+ </item>
+ <item>
+ <p>
+ Specifying a scope to binary:match/3 when using multiple
+ searchstrings resulted in faulty return values. This is
+ now corrected.</p>
+ <p>
+ Own Id: OTP-9701</p>
+ </item>
+ <item>
+ <p>
+ The runtime system crashed if more than one thread tried
+ to exit the runtime system at the same time.</p>
+ <p>
+ Own Id: OTP-9705</p>
+ </item>
+ <item>
+ <p>
+ Fix documentation for erlang:process_flag/2</p>
+ <p>
+ For the subsection about process_flag(save_calls, N)
+ there's an unrelated paragraph about process priorities
+ which was copied from the preceeding subsection regarding
+ process_flag(priority, Level). (Thanks to Filipe David
+ Manana)</p>
+ <p>
+ Own Id: OTP-9714</p>
+ </item>
+ <item>
+ <p>
+ Calls to <c>erlang:system_flag(schedulers_online, N)</c>
+ and/or <c>erlang:system_flag(multi_scheduling,
+ block|unblock)</c> could cause internal data used by this
+ functionality to get into an inconsistent state. When
+ this happened various problems occurred. This bug was
+ quite hard to trigger, so hopefully no-one has been
+ effected by it.</p>
+ <p>
+ A spinlock used by the run-queue management sometimes got
+ heavily contended. This code has now been rewritten, and
+ the spinlock has been removed.</p>
+ <p>
+ Own Id: OTP-9727</p>
+ </item>
+ <item>
+ <p>
+ Use libdlpi to get physical address (Thanks to Trond
+ Norbye)</p>
+ <p>
+ Own Id: OTP-9818</p>
+ </item>
+ </list>
+ </section>
+
+
+ <section><title>Improvements and New Features</title>
+ <list>
+ <item>
+ <p> An option list argument can now be passed to
+ <c>file:read_file_info/2, file:read_link_info/2</c> and
+ <c>file:write_file_info/3</c> and set time type
+ information in the call. Valid options are <c>{time,
+ local}, {time, universal}</c> and <c>{time, posix}</c>.
+ In the case of <c>posix</c> time no conversions are made
+ which makes the operation a bit faster. </p>
+ <p>
+ Own Id: OTP-7687</p>
+ </item>
+ <item>
+ <p>A number of memory allocation optimizations have been
+ implemented. Most optimizations reduce contention caused
+ by synchronization between threads during allocation and
+ deallocation of memory. Most notably:</p> <list> <item>
+ Synchronization of memory management in scheduler
+ specific allocator instances has been rewritten to use
+ lock-free synchronization. </item> <item> Synchronization
+ of memory management in scheduler specific pre-allocators
+ has been rewritten to use lock-free synchronization.
+ </item> <item> The 'mseg_alloc' memory segment allocator
+ now use scheduler specific instances instead of one
+ instance. Apart from reducing contention this also
+ ensures that memory allocators always create memory
+ segments on the local NUMA node on a NUMA system. </item>
+ </list>
+ <p>
+ Own Id: OTP-7775</p>
+ </item>
+ <item>
+ <p>
+ The ethread atomic memory operations API used by the
+ runtime system has been extended and improved.</p>
+ <p>
+ The ethread library now also performs runtime tests for
+ presence of hardware features, such as for example SSE2
+ instructions, instead of requiring this to be determined
+ at compile time.</p>
+ <p>
+ All uses of the old deprecated atomic API in the runtime
+ system have been replaced with the use of the new atomic
+ API. In a lot of places this change imply a relaxation of
+ memory barriers used.</p>
+ <p>
+ Own Id: OTP-9014</p>
+ </item>
+ <item>
+ <p>gen_sctp:open/0-2 may now return
+ {error,eprotonosupport} if SCTP is not supported</p>
+ <p>gen_sctp:peeloff/1 has been implemented and creates a
+ one-to-one socket which also are supported now</p>
+ <p>
+ *** POTENTIAL INCOMPATIBILITY ***</p>
+ <p>
+ Own Id: OTP-9239</p>
+ </item>
+ <item>
+ <p>
+ Sendfile has been added to the file module's API.
+ sendfile/2 is used to read data from a file and send it
+ to a tcp socket using a zero copying mechanism if
+ available on that OS.</p>
+ <p>
+ Thanks to Tuncer Ayaz and Steve Vinovski for original
+ implementation</p>
+ <p>
+ Own Id: OTP-9240</p>
+ </item>
+ <item>
+ <p>
+ enif_get_reverse_list function added to nif API. This
+ function should be used to reverse small lists which are
+ deep within other structures making it impractical to do
+ the reverse in Erlang.</p>
+ <p>
+ Own Id: OTP-9392</p>
+ </item>
+ <item>
+ <p>
+ The deprecated concat_binary/1 BIF has been removed. Use
+ <c>list_to_binary</c> or <c>iolist_to_binary/1</c>
+ instead.</p>
+ <p>
+ *** POTENTIAL INCOMPATIBILITY ***</p>
+ <p>
+ Own Id: OTP-9421</p>
+ </item>
+ <item>
+ <p>Erlang/OTP can now be built using parallel make if you
+ limit the number of jobs, for instance using '<c>make
+ -j6</c>' or '<c>make -j10</c>'. '<c>make -j</c>' does not
+ work at the moment because of some missing
+ dependencies.</p>
+ <p>
+ Own Id: OTP-9451</p>
+ </item>
+ <item>
+ <p>Line number and filename information are now included
+ in exception backtraces as a fourth element in the MFA
+ tuple. The information will be pretty-printed by the
+ shell and used by <c>common_test</c> to provide better
+ indication of where a test case.</p>
+ <p>
+ *** POTENTIAL INCOMPATIBILITY ***</p>
+ <p>
+ Own Id: OTP-9468</p>
+ </item>
+ <item>
+ <p>All binary constants used to be handled as heap
+ binaries (i.e. the entire binary would be copied when
+ sent to another process). Binary constants larger than 64
+ bytes are now refc binaries (i.e. the actual data in the
+ binary will not be copied when sent to another
+ process).</p>
+ <p>
+ Own Id: OTP-9486</p>
+ </item>
+ <item>
+ <p>
+ If a float and an integer is compared, the integer is
+ only converted to a float if the float datatype can
+ contain it. Otherwise the float is converted to an
+ integer.</p>
+ <p>
+ *** POTENTIAL INCOMPATIBILITY ***</p>
+ <p>
+ Own Id: OTP-9497</p>
+ </item>
+ <item>
+ <p>
+ Add NIF function enif_is_number</p>
+ <p>
+ This function allows for easily determining if a term
+ represents or not a number (integer, float, small or
+ big).(Thanks to Filipe David Manana)</p>
+ <p>
+ Own Id: OTP-9629</p>
+ </item>
+ <item>
+ <p>
+ The ERTS internal system block functionality has been
+ replaced by new functionality for blocking the system.
+ The old system block functionality had contention issues
+ and complexity issues. The new functionality piggy-backs
+ on thread progress tracking functionality needed by newly
+ introduced lock-free synchronization in the runtime
+ system. When the functionality for blocking the system
+ isn't used, there is more or less no overhead at all.
+ This since the functionality for tracking thread progress
+ is there and needed anyway.</p>
+ <p>
+ Own Id: OTP-9631</p>
+ </item>
+ <item>
+ <p>
+ An ERTS internal, generic, many to one, lock-free queue
+ for communication between threads has been introduced.
+ The many to one scenario is very common in ERTS, so it
+ can be used in a lot of places in the future. Currently
+ it is used by scheduling of certain jobs, and the async
+ thread pool, but more uses are planned for the future.</p>
+ <p>
+ Drivers using the driver_async functionality are not
+ automatically locked to the system anymore, and can be
+ unloaded as any dynamically linked in driver.</p>
+ <p>
+ Scheduling of ready async jobs is now also interleaved in
+ between other jobs. Previously all ready async jobs were
+ performed at once.</p>
+ <p>
+ Own Id: OTP-9632</p>
+ </item>
+ <item>
+ <p>
+ Tuple funs (a two-element tuple with a module name and a
+ function) are now officially deprecated and will be
+ removed in R16. Use '<c>fun M:F/A</c>' instead. To make
+ you aware that your system uses tuple funs, the very
+ first time a tuple fun is applied, a warning will be sent
+ to the error logger.</p>
+ <p>
+ Own Id: OTP-9649</p>
+ </item>
+ <item>
+ <p>
+ Changed the internal BIF calling convention. Will make
+ simpler faster code and allow BIFs with an arbitrary
+ arity.</p>
+ <p>
+ Own Id: OTP-9662</p>
+ </item>
+ <item>
+ <p>
+ Windows native critical sections are now used internally
+ in the runtime system on Windows as mutex implementation.
+ This since they perform better under extreme contention
+ than our own implementation.</p>
+ <p>
+ Own Id: OTP-9671</p>
+ </item>
+ <item>
+ <p>
+ Convert some erl_nif macros into inline functions. Allow
+ for better compile time type checking. (Thanks to Tuncer
+ Ayaz)</p>
+ <p>
+ Own Id: OTP-9675</p>
+ </item>
+ <item>
+ <p>
+ The <c>+scl</c> command line flag has been added. It can
+ be used for disabling compaction of scheduler load. For
+ more information see the <c>erl(1)</c> documentation.</p>
+ <p>
+ Own Id: OTP-9695</p>
+ </item>
+ <item>
+ <p>The build system has been updated so that Erlang/OTP
+ can be built on Mac OS X Lion systems without a GCC
+ compiler. The INSTALL guide has been updated with
+ instructions on how to install a GCC compiler and build
+ Erlang/OTP with it, in order to get a run-time system
+ with better performance.</p>
+ <p>
+ Own Id: OTP-9712</p>
+ </item>
+ <item>
+ <p>
+ When loading a module, the system use to run on a single
+ scheduler during the entire loading process. This has
+ been changed to only take down the system just before
+ inserting the loaded code into the system tables,
+ resulting in a much shorter disruption if a module is
+ loaded in a busy system. (Suggested by Bob Ippolito.)</p>
+ <p>
+ Own Id: OTP-9720</p>
+ </item>
+ <item>
+ <p>
+ Possible to run HiPE without floating point exceptions
+ (FPE). Useful on platforms that lack reliable FPE. Slower
+ float operations compared to HiPE with FPE.</p>
+ <p>
+ Own Id: OTP-9724</p>
+ </item>
+ <item>
+ <p>
+ As of ERTS version 5.9 (OTP-R15B) the runtime system will
+ by default <em>not</em> bind schedulers to logical
+ processors.</p>
+ <p>
+ 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. In some cases this performance penalty might be
+ severe. Due to this, we change the default so that the
+ user must make an active decision in order to bind
+ schedulers.</p>
+ <p>
+ *** POTENTIAL INCOMPATIBILITY ***</p>
+ <p>
+ Own Id: OTP-9726</p>
+ </item>
+ <item>
+ <p>
+ The use of <c>erlang:system_flag(scheduler_bind_type,
+ _)</c> and <c>erlang:system_flag(cpu_topology, _)</c>
+ have been deprecated and scheduled for removal in
+ erts-5.10/OTP-R16. For more information see the
+ documentation of <c>erlang:system_flag/2</c>.</p>
+ <p>
+ *** POTENTIAL INCOMPATIBILITY ***</p>
+ <p>
+ Own Id: OTP-9749</p>
+ </item>
+ <item>
+ <p>
+ An ancient workaround for a Windows bug was removed from
+ the open_port code, open_port({spawn,...}...) is now
+ faster. Thanks to Daniel Goertzen.</p>
+ <p>
+ Own Id: OTP-9766</p>
+ </item>
+ <item>
+ <p>
+ The use of deprecated 32bit time_t on 32bit Windows is
+ removed.</p>
+ <p>
+ Own Id: OTP-9767</p>
+ </item>
+ <item>
+ <p>
+ The NIF <c>reload</c> mechanism is deprecated. Do not use
+ it as an upgrade method for live production systems. It
+ might be removed in future releases. It can still serve
+ as a development feature but a warning message will be
+ logged each time it is used.</p>
+ <p>
+ *** POTENTIAL INCOMPATIBILITY ***</p>
+ <p>
+ Own Id: OTP-9771</p>
+ </item>
+ <item>
+ <p>The driver interface has been changed to enable 64-bit
+ aware drivers. Most importantly the return types for
+ ErlDrvEntry callbacks 'call' and 'control' has ben
+ enlarged which require drivers to be changed or they will
+ cause emulator crashes. See <seealso
+ marker="erl_driver#rewrites_for_64_bits"> Rewrites for
+ 64-bit driver interface </seealso> in the driver manual.
+ </p>
+ <p>Due to this driver <seealso
+ marker="erl_driver#version_management">version
+ management</seealso> is now mandatory. A driver that is
+ not written with version management or a driver that was
+ compiled with the wrong major version will be not be
+ loaded by the emulator.</p>
+ <p>
+ *** POTENTIAL INCOMPATIBILITY ***</p>
+ <p>
+ Own Id: OTP-9795</p>
+ </item>
+ <item>
+ <p>
+ Eliminate use of deprecated regexp module</p>
+ <p>
+ Own Id: OTP-9810</p>
+ </item>
+ </list>
+ </section>
+
+</section>
+
<section><title>Erts 5.8.5</title>
<section><title>Fixed Bugs and Malfunctions</title>