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diff --git a/erts/doc/src/notes.xml b/erts/doc/src/notes.xml index 6174917807..efe2dada9c 100644 --- a/erts/doc/src/notes.xml +++ b/erts/doc/src/notes.xml @@ -30,6 +30,480 @@ </header> <p>This document describes the changes made to the ERTS application.</p> +<section><title>Erts 5.8.1</title> + + <section><title>Fixed Bugs and Malfunctions</title> + <list> + <item> + <p> + Very small floating point numbers generated errors when + converting from list to float in some versions of the VM, + this is now corrected so that i.e. + list_to_float("1.0e-324"). returns 0.0 in all versions of + Erlang.</p> + <p> + Own Id: OTP-7178</p> + </item> + <item> + <p> + Windows Vista and Windows 7 file system virtualization, + which makes "old style" windows programs execute in a + file system sandbox, was previously unintentionally + turned on for the Erlang VM. This is now corrected so + that i.e. writes to C:\Program Files\. without + administrator privileges will fail.</p> + <p> + Own Id: OTP-7405</p> + </item> + <item> + <p> + Fix faulty 64-bit integer term output from drivers. Large + 64-bits integers did not generate correct bignums and + could even cause emulator crash. Only affects drivers + using ERL_DRV_INT64 or ERL_DRV_UINT64, introduced in + R13B03.</p> + <p> + Own Id: OTP-8716</p> + </item> + <item> + <p> + Fixed: inet:setopts(S, [{linger,{true,2}}]) returned + {error,einval} for SCTP sockets. The inet_drv had a bug + when checking the option size.</p> + <p> + Own Id: OTP-8726 Aux Id: seq11617 </p> + </item> + <item> + <p>Fix libm linking with --as-needed flag + <p> + When building with "--as-needed" linker flags on Linux + the build will fail. This has now been fixed.</p> + <p> + (Thanks to Christian Faulhammer)</p></p> + <p> + Own Id: OTP-8728</p> + </item> + <item> + <p> + gen_udp:connect/3 was broken for SCTP enabled builds. It + did not detect remote end errors as it should.</p> + <p> + Own Id: OTP-8729</p> + </item> + <item> + <p>Reduce the risk of integer wrapping in bin vheap size + counting.</p> <p>The vheap size series will now use the + golden ratio instead of doubling and fibonacci + sequences.</p> + <p> + Own Id: OTP-8730</p> + </item> + <item> + <p> + ETS ordered_set containing <c>[]</c> as key could cause + strange thing to happen, like an infinite hanging + <c>ets:select</c>.</p> + <p> + Own Id: OTP-8732</p> + </item> + <item> + <p>reference() has been substituted for ref() in the + documentation.</p> + <p> + Own Id: OTP-8733</p> + </item> + <item> + <p> + When a native compiled module called a not loaded + non-native compiled module that had an on_load function, + the export entries were trashed after code loading so on + the next call from the native compiled module to the + non-native compiled the emulator crashed. This bug has + now been fixed.</p> + <p> + Own Id: OTP-8736</p> + </item> + <item> + <p> + HiPE-enabled Erlang VMs running on BSD systems sometimes + generated messages like "Yikes! erts_alloc() returned + misaligned address 0x8016a512c". Fixed. (Thanks to Mikael + Pettersson.)</p> + <p> + Own Id: OTP-8769</p> + </item> + <item> + <p> + A race condition in <c>erts_poll()</c> could cause delay + of poll for I/O.</p> + <p> + Own Id: OTP-8773</p> + </item> + <item> + <p> + Removed some potential vulnerabilities from the Erlang + Port Mapper Daemon (epmd) and straightened up access + control. Also removed hazardous interfaces allowing + anyone on a machine to forcefully unregister other nodes. + This means that the ei_unregister/erl_unregister + interfaces in erl_interface is rendered not only error + prone and mystifying as before, but totally ineffective. + The old behaviour of unchecked node unregistering can be + restored if needed, see epmd documentation for details.</p> + <p> + *** POTENTIAL INCOMPATIBILITY ***</p> + <p> + Own Id: OTP-8780</p> + </item> + <item> + <p> Building in a source tree without prebuilt platform + independent build results failed on the SSL examples + when: </p> <list><item> cross building. This has been + solved by not building the SSL examples during a cross + build. </item><item> building on Windows. </item></list> + <p> + Own Id: OTP-8791</p> + </item> + <item> + <p> + inet:getsockopt for SCTP sctp_default_send_param had a + bug to not initialize required feilds causing random + answers. It is now corrected.</p> + <p> + Own Id: OTP-8795 Aux Id: seq11655 </p> + </item> + <item> + <p> + The hipe_bifs:get_hrvtime/0 BIF now always returns a real + value even if the "perfctr" Linux kernel extension is not + available. It used to return a dummy value. (Thanks to + Mikael Pettersson.)</p> + <p> + Own Id: OTP-8798</p> + </item> + <item> + <p> + Calling a native-code compiled module with an + <c>on_load</c> function could cause a crash. (Thanks to + Mikael Pettersson.)</p> + <p> + Own Id: OTP-8799</p> + </item> + <item> + <p>The emulator could crash while writing a crash dump if + native-compiled modules had been loaded. (Thanks to Paul + Guyot.)</p> + <p> + Own Id: OTP-8801</p> + </item> + <item> + <p> + The garbage collector could crash if invoked from + native-compiled code after a call to a BIF. (Thanks to + Paul Guyot.)</p> + <p> + Own Id: OTP-8821</p> + </item> + <item> + <p> + A rare memory leak in binary:matches is removed</p> + <p> + Own Id: OTP-8823</p> + </item> + <item> + <p>For a socket in the HTTP packet mode, the return value + from <c>gen_tcp:recv/2,3</c> if there is an error in the + header will be <c>{ok,{http_error,String}}</c> instead of + <c>{error,{http_error,String}}</c> to be consistent with + <c>ssl:recv/2,3</c>.</p> + <p> + *** POTENTIAL INCOMPATIBILITY ***</p> + <p> + Own Id: OTP-8831</p> + </item> + </list> + </section> + + + <section><title>Improvements and New Features</title> + <list> + <item> + <p> + ets:select_reverse/{1,2,3} are now documented.</p> + <p> + Own Id: OTP-7863</p> + </item> + <item> + <p> + External format of integers changed to make full use of + all 32 bits of INTEGER_EXT. This is a compatible change + as old code can read full 32-bit integers but only + produce 28-bit integers as INTEGER_EXT.</p> + <p> + Own Id: OTP-8540 Aux Id: seq11534 </p> + </item> + <item> + <p> + Large parts of the <c>ethread</c> library have been + rewritten. The <c>ethread</c> library is an Erlang + runtime system internal, portable thread library used by + the runtime system itself.</p> + <p> + Most notable improvement is a reader optimized rwlock + implementation which dramatically improve the performance + of read-lock/read-unlock operations on multi processor + systems by avoiding ping-ponging of the rwlock cache + lines. The reader optimized rwlock implementation is used + by miscellaneous rwlocks in the runtime system that are + known to be read-locked frequently, and can be enabled on + ETS tables by passing the <seealso + marker="stdlib:ets#new_2_read_concurrency">{read_concurrency, + true}</seealso> option upon table creation. See the + documentation of <seealso + marker="stdlib:ets#new/2">ets:new/2</seealso> for more + information. The reader optimized rwlock implementation + can be fine tuned when starting the runtime system. For + more information, see the documentation of the <seealso + marker="erts:erl#+rg">+rg</seealso> command line argument + of <c>erl</c>.</p> + <p> + There is also a new implementation of rwlocks that is not + optimized for readers. Both implementations interleaves + readers and writers during contention as opposed to, + e.g., the NPTL (Linux) pthread rwlock implementation + which use either a reader or writer preferred strategy. + The reader/writer preferred strategy is problematic since + it starves threads doing the non-preferred operation.</p> + <p> + The new rwlock implementations in general performs better + in ERTS than common pthread implementations. However, in + some extremely heavily contended cases this is not the + case. Such heavy contention can more or less only appear + on ETS tables. This when multiple processes do very large + amounts of write locked operations simultaneously on the + same table. Such use of ETS is bad regardless of rwlock + implementation, will never scale, and is something we + strongly advise against.</p> + <p> + The new rwlock implementations depend on atomic + operations. If no native atomic implementation is found, + a fallback solution will be used. Using the fallback + implies a performance degradation. That is, it is more + important now than before to build OTP with a native + atomic implementation.</p> + <p> + The <c>ethread</c> library contains native atomic + implementations for, x86 (32 and 64 bit), powerpc (32 + bit), sparc V9 (32 and 64 bit), and tilera (32 bit). On + other hardware gcc's builtin support for atomic memory + access will be used if such exists. If no such support is + found, <c>configure</c> will warn about no atomic + implementation available.</p> + <p> + The <c>ethread</c> library can now also use the + <c>libatomic_ops</c> library for atomic memory accesses. + This makes it possible for the Erlang runtime system to + utilize optimized native atomic operations on more + platforms than before. If <c>configure</c> warns about no + atomic implementation available, try using the + <c>libatomic_ops</c> library. Use the <seealso + marker="doc/installation_guide:INSTALL#How-to-Build-and-Install-ErlangOTP_A-Closer-Look-at-the-individual-Steps_Configuring">--with-libatomic_ops=PATH</seealso> + <c>configure</c> command line argument when specifying + where the <c>libatomic_ops</c> installation is located. + The <c>libatomic_ops</c> library can be downloaded from: + <url + href="http://www.hpl.hp.com/research/linux/atomic_ops/">http://www.hpl.hp.com/research/linux/atomic_ops/</url></p> + <p> + The changed API of the <c>ethread</c> library has also + caused modifications in the Erlang runtime system. + Preparations for the to come "delayed deallocation" + feature has also been done since it depends on the + <c>ethread</c> library.</p> + <p> + <em>Note</em>: When building for x86, the <c>ethread</c> + library will now use instructions that first appeared on + the pentium 4 processor. If you want the runtime system + to be compatible with older processors (back to 486) you + need to pass the <seealso + marker="doc/installation_guide:INSTALL#How-to-Build-and-Install-ErlangOTP_A-Closer-Look-at-the-individual-Steps_Configuring">--enable-ethread-pre-pentium4-compatibility</seealso> + <c>configure</c> command line argument when configuring + the system.</p> + <p> + Own Id: OTP-8544</p> + </item> + <item> + <p> + erlang:localtime_to_universaltime({{2008, 8, 1}, {0, 0, + 0}},true) when TZ=UTC now behaves consistently on all + Unix platforms.</p> + <p> + The problem fixed was originally reported by Paul Guyot + on erlang-bugs mailing list:</p> + <p> + http://www.erlang.org/pipermail/erlang-bugs/2008-November/001077.html</p> + <p> + Own Id: OTP-8580</p> + </item> + <item> + <p> + Optimization reducing memory consumption by two words per + ETS object.</p> + <p> + Own Id: OTP-8737</p> + </item> + <item> + <p> + Fixes for unsupported halfword-emulator</p> + <p> + Own Id: OTP-8745</p> + </item> + <item> + <p> + NIF 64-bit integer support; <c>enif_get_int64</c>, + <c>enif_get_uint64</c>, <c>enif_make_int64</c>, + <c>enif_make_uint64</c>.</p> + <p> + Own Id: OTP-8746</p> + </item> + <item> + <p> + Alignment of trailing data in messages has been adjusted. + This in order to be able to pass data of any type as + trailing data in the future.</p> + <p> + Own Id: OTP-8754</p> + </item> + <item> + <p> + The obsolete/driver.h header file has been removed. It + has been obsolete and deprecated since R8B. Drivers that + still include obsolete/driver.h must be updated to + include erl_driver.h.</p> + <p> + *** POTENTIAL INCOMPATIBILITY ***</p> + <p> + Own Id: OTP-8758</p> + </item> + <item> + <p> + Added erlang:system_info(build_type) which makes it + easier to chose drivers, NIF libraries, etc based on + build type of the runtime system.</p> + <p> + The NIF library for crypto can now be built for valgrind + and/or debug as separate NIF libraries that will be + automatically loaded if the runtime system has been built + with a matching build type.</p> + <p> + Own Id: OTP-8760</p> + </item> + <item> + <p> + Further lessened the memory requirements of ETS objects.</p> + <p> + Own Id: OTP-8762</p> + </item> + <item> + <p>The broken elib_malloc alternate memory allocator has + been removed. <c>erlang:system_info(elib_malloc)</c> will + always return <c>false</c>, and in R15, + <c>erlang:system_info(elib_malloc)</c> will fail with a + <c>badarg</c> exception.</p> + <p> + Own Id: OTP-8764</p> + </item> + <item> + <p> + Calling <c>erlang:system_info/1</c> with the new argument + <c>update_cpu_info</c> will make the runtime system + reread and update the internally stored CPU information. + For more information see the documentation of <seealso + marker="erlang#update_cpu_info">erlang:system_info(update_cpu_info)</seealso>.</p> + <p> + The CPU topology is now automatically detected on Windows + systems with less than 33 logical processors. The runtime + system will now, also on Windows, by default bind + schedulers to logical processors using the + <c>default_bind</c> bind type if the amount of schedulers + is 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> + Own Id: OTP-8765</p> + </item> + <item> + <p> + The SMP ERTS internal child waiter thread used on Linux + system with NPTL was unintentionally disabled during + cross compilation rewrites (OTP-8323 in R13B03). It has + now been re-enabled. Enabling it again gives a slight + performance improvement.</p> + <p> + Own Id: OTP-8774</p> + </item> + <item> + <p> + <c>epmd</c> used to generate a message to the syslog when + it started up, which could be annoying. This has been + changed to only generate the message if the debug swith + is given. (Thanks to Michael Santos.)</p> + <p> + Own Id: OTP-8775</p> + </item> + <item> + <p> + The scheduler wakeup threshold is now possible to adjust + at system boot. For more information see the <seealso + marker="erl#+swt">+swt</seealso> command line argument of + <c>erl</c>.</p> + <p> + Own Id: OTP-8811</p> + </item> + <item> + <p> + The undocumented function inet:ifget/2 has been improved + to return interface hardware address (MAC) on platforms + supporting getaddrinfo() (such as BSD unixes). Note it + still does not work on all platforms for example not + Windows nor Solaris, so the function is still + undocumented.</p> + <p> + Buffer overflow and field init bugs for inet:ifget/2 and + inet:getservbyname/2 has also been fixed.</p> + <p> + Thanks to Michael Santos.</p> + <p> + Own Id: OTP-8816</p> + </item> + <item> + <p> + Optimizations for MIPS when using gcc atomics. (Thanks to + Steve Vinoski)</p> + <p> + Own Id: OTP-8834</p> + </item> + <item> + <p> + Lock optimization in timer functionality.</p> + <p> + Own Id: OTP-8835</p> + </item> + </list> + </section> + + + <section><title>Known Bugs and Problems</title> + <list> + <item> + <p>Fix epmd and build environment to build on VxWorks</p> + <p> + Own Id: OTP-8838</p> + </item> + </list> + </section> + +</section> + <section><title>Erts 5.8</title> <section><title>Fixed Bugs and Malfunctions</title> |