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Putenv and getenv needs to convert to the proper environment
strings in Unicode depending on platform and user settings for filename
encoding. Also erlexec needs to pass environment strings in an appropriate
way for kernel to pick up. All environment strings on the command
line, as well as home directory, is now passed in UTF8 on windows
and in whatever encoding you have on Unix, kernel tries to convert all
parameters and environments from UTF8 before making strings.
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* lukas/otp/install_with_whitespace/OTP-10107:
Update to work with space in include path
Update to work with whitespace in exec path
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OTP-10106
OTP-10107
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The hybrid heap emulator was last working in the non-SMP R11B
run-time system. When the constant pools were introduced in R12B,
the hybrid heap emulator was not updated to handle them.
At this point, the harm from reduced readability of the code is
greater than any potential usefulness of keeping the code.
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* rickard/sched-busy-wait/OTP-10044:
Add switch controlling scheduler busy wait
Conflicts:
erts/emulator/beam/erl_process.c
erts/emulator/beam/erl_process.h
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rickard/sched-wakeup-other-r15b01/OTP-10033
Conflicts:
erts/emulator/beam/erl_process.c
erts/vsn.mk
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* rickard/sched-compact-load/OTP-9695:
Add switch that can disable scheduler compaction of load
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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:
* Synchronization of memory management in scheduler specific allocator
instances has been rewritten to use lock-free synchronization.
* Synchronization of memory management in scheduler specific
pre-allocators has been rewritten to use lock-free synchronization.
* 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.
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The contents of the ERL_<version>_FLAGS undocumented environment
variable would be added at the end of the command line passed
to the BEAM emualator (similar to ERL_ZFLAGS), making it impossible
to override (for example) "-smp" with "-smp disable" on the command
line.
To allow overriding, put the contents of ERL_<version>_FLAGS at
the beginning of the command line (similar to ERL_AFLAGS).
Since the ERL_<version>_FLAGS variable is undocumented and
unsupported, it is OK to change its behaviour in a minor release.
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It is difficult/impossible to find out whether an invocation of
'erl' will start the smp emulator or the non-smp emulator
(short of actually starting the emulator). Therefore we will need
a way to ask 'erlexec'.
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* sf/erts_de_busy_limit:
Add flag-based setting for the distribution buffer busy limit
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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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Truncate buffer operations on environment variables.
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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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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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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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* 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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The erl (and beam) start arguments are extended with
the following options:
* +hms Size, sets the default minimum heap size
for processes.
* +hmbs Size, sets the default minimum binary virtual heap
size for processes.
The previous +h Size argument can still be used for backward
compatibility purposes.
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