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* rickard/deprecate-runtime-binding/OTP-9749:
Deprecate erlang:system_flag/2 arguments scheduler_bind_type and cpu_topology
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The use of erlang:system_flag(scheduler_bind_type, _) and
erlang:system_flag(cpu_topology, _) have been deprecated and scheduled
for removal in erts-5.10/OTP-R16. For more information see the
documentation of erlang:system_flag/2.
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* rickard/default-unbound/OTP-9726:
Use unbound schedulers as default
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As of ERTS version 5.9 (OTP-R15B) the runtime system will by default
not bind schedulers to logical processors.
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.
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* rickard/sched-compact-load/OTP-9695:
Add switch that can disable scheduler compaction of load
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* hw/epmd-bind-to-address:
Allow user to specify the IP address epmd binds to
OTP-9213
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* gl/erts-doterlang-docs:
Add back documentation on .erlang processing
OTP-9189
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Clarify that specifying "-noinput" is unnecessary if the "-detached"
flag is given.
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The compressed format is using a slighty modified variant of the extern format
(term_to_binary). To not worsen key lookup's too much, the top tuple itself
and the key element are not compressed. Table objects with only immediate
non-key elements will therefor not gain anything (but actually consume one
extra word for "alloc_size").
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* pg/freebsd-cpu-affinity-and-topology:
Add support for CPU affinity & topology detection on FreeBSD 8
OTP-8939
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The IP address(es) epmd binds to can now be specified by the user,
either via epmd's new "-address" option or (if that's not used) by
setting the environment variable ERL_EPMD_ADDRESS. Multiple addresses
may be specified using a comma-separated list. If the loopback address
is not in this list, it will be added implicitly, so that the daemon can
be queried by an interactive epmd process.
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The runtime system is now less eager to suspend
processes sending messages over the distribution. The
default value of the distribution buffer busy limit
has also been increased from 128 KB to 1 MB. This in
order to improve throughput.
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Id: OTP-8912
This patch creates a new family of flags with the "+z" prefix. It
further creates a new configuration option called "dbbl" (which is the
first letter of the name dist_buf_busy_limit). Example usage of this
flag would be "+zdbbl 1048576".
This patch creates an adjustable buffer limit for the amount of data
that may be buffered by the erlang distribution code (in dist.c
specifically). Before this patch, this hard-coded constant was used:
#define ERTS_DE_BUSY_LIMIT (128*1024)
When large binaries are transmitted between nodes (or simply a lot of
medium-sized binaries), it is very easy to hit the old 128KB limit.
Processes that use the erlang:system_monitor() BIF to monitor system
events can be spammed by {monitor, busy_dist_port, ...} message tuples
at rates of tens to even hundreds of messages/second.
A larger buffer limit will allow processes to buffer more outgoing
messages over the distribution. When the buffer limit has been
reached, sending processes will be suspended until the buffer size has
shrunk. The buffer limit is per distribution channel. A higher limit
will give lower latency and higher throughput at the expense of
higher memory usage.
A variation of this patch has been in commercial production use in at
least two companies that the author is aware of. Larger buffer values
can reduce the number of {monitor, busy_dist_port, ...} system
messages drastically, lower overall messaging latencies, and prevent
false timeouts and 'nodedown' messages in extremely busy Mnesia systems.
Test suite: there are two tests:
a. In erlexec_SUITE.erl to test basic set & get of the value
b. In distribution_SUITE.erl, to verify that setting +zdbbl very
low will actually change behavior.
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The scheduler wakeup threshold is now possible to adjust at system boot.
For more information see the `+swt' command line argument of `erl'.
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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 'default_bind' 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.
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Large parts of the ethread library have been rewritten. The
ethread library is an Erlang runtime system internal, portable
thread library used by the runtime system itself.
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
`{read_concurrency, true}' option upon table creation. See the
documentation of `ets:new/2' for more information.
The ethread library can now also use the libatomic_ops library
for atomic memory accesses. This makes it possible for the
Erlang runtime system to utilize optimized atomic operations
on more platforms than before. Use the
`--with-libatomic_ops=PATH' configure command line argument
when specifying where the libatomic_ops installation is
located. The libatomic_ops library can be downloaded from:
http://www.hpl.hp.com/research/linux/atomic_ops/
The changed API of the ethread 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 ethread library.
Note: When building for x86, the ethread 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
`--enable-ethread-pre-pentium4-compatibility' configure command
line argument when configuring the system.
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The runtime system will by default bind schedulers to logical processors
using the default_bind 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.
NOTE: 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(schedule
r_bind_type, unbound)</seealso>.
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* bd/doc-fixes:
Fix minor documentation errors
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Fix three minor typos and reorder one of a pair of lists of functions so that
the ordering is consistent.
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It is now possible to increase or decrease the maximum number of atoms
the VM can handle. The default value is 1048576 (1024*1024).
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environment after a number of bugs are fixed and some features
are added in the documentation build process.
- The arity calculation is updated.
- The module prefix used in the function names for bif's are
removed in the generated links so the links will look like
http://www.erlang.org/doc/man/erlang.html#append_element-2
instead of
http://www.erlang.org/doc/man/erlang.html#erlang:append_element-2
- Enhanced the menu positioning in the html documentation when a
new page is loaded.
- A number of corrections in the generation of man pages (thanks
to Sergei Golovan)
- Moved some man pages to more apropriate sections, pages in
section 4 moved to 5 and pages in 6 moved to 7.
- The legal notice is taken from the xml book file so OTP's
build process can be used for non OTP applications.
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* egil/binary-gc:
Add documentation for binary heap size settings.
Add tracing capabilities for binary virtual heap
Add min heap size start options to beam and erl
Improve binary garbage collection
OTP-8370 The default settings for garbage collection of binaries has been
adjusted to be less aggressive than in R13B03. It is now also
possible configure the settings for binary GC. See the
documentation for spawn_opt/2-5, erlang:system_info/1,
erlang:system_flag/2, process_flag/2-3, erlang:trace/3, and the
documenation for erl for the new command line options +hms and
+hmbs.
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Documentation of min_heap_size and min_bin_vheap size for:
* spawn_opt/2, spawn_opt/3, spawn_opt/4, spawn_opt/5
* erlang:system_flag/2
* erlang:system_info/1
* process_flag/2
* process_info/2
* erlang:trace/3
Documentation for the new beam start arguments:
+hms Size, Default minimum heap size for processes.
+hmbs Size, Default minimum binary virtual heap size.
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