This document lists some highlights of Erlang 5.5/OTP R11B (unpatched), compared to the previous version Erlang 5.4/OTP R10B, with focus on things not already released as R10B patches.
Note: This document was compiled at the time when R11B was released and does not list any features introduced in R11B patches.
The major news is the support for SMP (Symmetric MultiProcessing).
SMP is supported by most modern operating systems like Linux, Windows, Mac OSx, Solaris and is becoming more important now when dual processors, hyper-threading technology and multi-core systems are a reality.
With Erlang, most of the problems which occur in multi-threaded programs have been solved once and for all in the Erlang VM and do not have to be handled by the application programmers.
In the SMP version of the Erlang virtual machine, there can be many process schedulers running in separate OS threads. As default there will be as many schedulers as there are processors or processor cores on the system.
The SMP support is totally transparent for the Erlang programs. That is, there is no need to change or recompile existing programs. Programs with built-in assumptions about sequential execution must be rewritten in order to take advantage of the SMP support, however.
In this release, the Erlang VM supports SMP with focus on stability. There will follow a number of subsequent steps with necessary optimizations and support for more platforms.
The Erlang VM with SMP support has been tested on the following platforms:
Some promising benchmarks:
Sun Fire T2000 Server, Solaris 10, UltraSPARC T1 Processor which is an 8 core CPU with 4 threads per core. Comparison between single-threaded Erlang VM and Erlang SMP VM with 32 schedulers.
no SMP | SMP 32 | |
Big | 1 | 14 |
Encode-decode | 1 | 7 |
ADM Opteron: 2 dual core CPUs running Suse Linux Enterprise Server 9. Comparison between single-threaded Erlang VM and Erlang SMP VM with 4 schedulers.
no SMP | SMP 4 | |
Big | 1 | 5 |
Encode-decode | 1 | 3.6 |
Intel Xeon: 2 Hyper-threaded processors running Suse Linux Enterprise Server 9 Comparison between single-threaded Erlang VM and Erlang SMP VM with 4 schedulers.
no SMP | SMP 4 | |
Big | 1 | 2.5 |
Encode-decode | 1 | 3.7 |
AMD Athlon (tm): 64 X2 Dual Core Processor 4200+, 2x512Kb L2 Cache, Linux Fedora Core 5; 2.6.16-1.2096_FC5.
no SMP | SMP 2 | |
Big | 1 | 2.8 |
Encode-decode | 1 | 2.3 |
See ERTS Release Notes.
andalso
and orelse
operators are now
allowed to be used in guards. That also applies to match
specifications. See
Erlang Reference Manual.is_record/3
can now be used in guards. Also,
is_record/3
can now be called without an
erlang:
module prefix for consistency with the other
is_*
functions. See
erlang(3).ignore_try
and
ignore_cond
, which allowed code that used unquoted
try
or cond
as atoms or record tags, has been
removed. Old code that depended on the options need to be
revised to have occurrences of try
or cond
as
atom or record tags single-quoted. (Note: Although cond
is a reserved keyword, there is no cond
statement. It
might be introduced in a future release.)fun M:F/A
construct creates a
fun that refers to the latest version of M:F/A
. This
syntax is meant to replace tuple funs {M,F}
which have
many problems. See
Erlang Reference Manual.is_function(Fun, Arity)
-- which may be used in guards -- test whether Fun
is
a fun that can be applied to Arity
arguments. See
erlang(3).
Dialyzer is a static analysis tool that identifies software discrepancies such as type errors, unreachable code, unnecessary tests, etc in single Erlang modules or entire (sets of) applications. See Dialyzer documentation.
The Inviso application, together with some new extensions to Runtime_Tools, is aimed at providing features for efficient tracing of production Erlang/OTP systems:
Inviso is still under development. An easier-to-use trace tool, using the features listed above, is planned to be released as an R11B patch in Q3/Q4 2006. See Inviso documentation.
The SSH application is an Erlang implementation of the secure shell protocol. It is considered to be a beta release, meaning there can be changes made to the API before it reaches 1.0. See SSH documentation.
(Compiler 4.3.6) It is now possible to encrypt the debug information in Beam files. See beam_lib(3).
(Debugger 2.0)
The debugger can now handle the try/catch
language
construct.
The Erlang implementation of the TFTP procotcol, tftp
,
is now documented.
See tftp(3).
In Kernel 2.10.X, several bug fixes and improvements have been
made in global
, the global name registration facility.
See Kernel Release Notes.
(OS_Mon 2.0) The entire OS_Mon application (code and documentation) has been reviewed and consequently updated with the goal to make the application more robust, homogeneous and easier to configure. See OS_Mon Release Notes.
Added the zip
module with functions for reading and
creating zip archives.
See zip(3).