Age | Commit message (Collapse) | Author |
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OTP-14899
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Communication between Erlang processes has conceptually always been
performed through asynchronous signaling. The runtime system
implementation has however previously preformed most operation
synchronously. In a system with only one true thread of execution, this
is not problematic (often the opposite). In a system with multiple threads
of execution (as current runtime system implementation with SMP support)
it becomes problematic. This since it often involves locking of structures
when updating them which in turn cause resource contention. Utilizing
true asynchronous communication often avoids these resource contention
issues.
The case that triggered this change was contention on the link lock due
to frequent updates of the monitor trees during communication with a
frequently used server. The signal order delivery guarantees of the
language makes it hard to change the implementation of only some signals
to use true asynchronous signaling. Therefore the implementations
of (almost) all signals have been changed.
Currently the following signals have been implemented as true
asynchronous signals:
- Message signals
- Exit signals
- Monitor signals
- Demonitor signals
- Monitor triggered signals (DOWN, CHANGE, etc)
- Link signals
- Unlink signals
- Group leader signals
All of the above already defined as asynchronous signals in the
language. The implementation of messages signals was quite
asynchronous to begin with, but had quite strict delivery constraints
due to the ordering guarantees of signals between a pair of processes.
The previously used message queue partitioned into two halves has been
replaced by a more general signal queue partitioned into three parts
that service all kinds of signals. More details regarding the signal
queue can be found in comments in the erl_proc_sig_queue.h file.
The monitor and link implementations have also been completely replaced
in order to fit the new asynchronous signaling implementation as good
as possible. More details regarding the new monitor and link
implementations can be found in the erl_monitor_link.h file.
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Just to simplify and get 4 distinctive states
IDLE, PENDING, CONNECTED and EXITING.
The old possible flag combos were:
0
PENDING
CONNECTED
CONNECTED|EXITING
EXITING
The two EXITING states did not serve any purpose
other then as a slight optimization in monitor_node(_,false,_)
to shortcut EXITING when there can be no monitors.
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to only transcode if output buffer actually contains
unsupported BIT_BINARY_EXT or EXPORT_EXT.
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to replace DFLAGS_STRICT_ORDER_DELIVERY
and remove that compile time dependency.
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for kernel to ask erts about distribution flags
and keep this info in one place.
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by suppressing DOP_MONITOR_P, DOP_MONITOR_P_EXIT and DOP_DEMONITOR_P
if not supported by the remote node.
In 17e198d6ee60f7dec9abfed272cf4226aea44535
I changed the behavior of erlang:monitor
to not raise badarg for c-nodes but instead create
a monitor to only supervise the connection.
But I forgot to prevent DOP_MONITOR_P and friends from being
sent to the node that does not expect them.
Note: We test both DFLAG_DIST_MONITOR and DFLAG_DIST_MONITOR_NAME
for the node to support process monitoring. This is because
erl_interface is buggy as it sets DFLAG_DIST_MONITOR without
really supporting it.
ToDo: Should erl_interface stop setting DFLAG_DIST_MONITOR
or should we change the meaning of these flags?
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Don't need to be pointer-pointer
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and abort_pending_connection into own utility function.
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to make sure it's kept alive.
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to avoid tuple fallbacks for export funs and bitstrings.
ToDo: Re-encode if receiver turn out to be erl_interface/jinterface.
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Conflicts:
erts/emulator/beam/bif.c
erts/emulator/beam/dist.c
erts/emulator/beam/dist.h
erts/emulator/beam/erl_bif_info.c
erts/emulator/beam/erl_node_tables.c
erts/emulator/beam/erl_node_tables.h
erts/emulator/beam/external.c
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This reverts commit 65b04e233e09e3cc2e0fda3c28e155b95c5a4baf.
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term_to_binary will always generate utf8 atoms
ATOM_UTF8_EXT and SMALL_ATOM_UTF8_EXT.
Old latin1 atoms, ATOM_EXT and SMALL_ATOM_EXT, are still decoded.
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* fix-source-typos: (25 commits)
Fixed typos in system/doc
Fixed typos in lib/xmerl
Fixed typos in lib/wx
Fixed typos in lib/stdlib
Fixed typos in lib/snmp
Fixed typos in lib/ssl
Fixed typos in lib/ssh
Fixed typos in PKCS-8.asn1 file
Fixed typos in lib/parsetools
Fixed typos in lib/orber
Fixed typos in lib/mnesia
Fixed typos in lib/megaco
Fixed typos in lib/kernel
Fixed typos in lib/jinterface
Fixed typos in lib/inets
Fixed typos in lib/hipe
Fixed typos in lib/eunit
Fixed typos in lib/erl_interface
Fixed typos in lib/eldap
Fixed typos in lib/edoc
...
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A magic destructor can return 0 and thereby take control
and prolong the lifetime of a magic binary.
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* henrik/update-copyrightyear:
update copyright-year
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to let future nodes know that we can handle
NEW_PID_EXT, NEW_PORT_EXT and NEWER_REFERENCE_EXT.
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to handle the "start of list" case in one place and not seven.
Note that this commit reverts (47d6fd3ccf35) back to using WSTACK
and pushing raw pointers. We disable GC while yielding, so this should not
be a problem.
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Use same mechanism as term_to_binary to yield
while encoding large messages for distributed send.
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This is just a preparation to allow detection of older nodes
that do not understand maps (R16 and older).
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This change was triggered by the OSE float printing function
not working exactly the same way as linux/win32. But it is
also a good one in general as it cuts size in more than half
for floats.
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* sverk/r16/utf8-atoms:
erl_interface: Fix bug when transcoding atoms from and to UTF8
erl_interface: Changed erlang_char_encoding interface
erts: Testcase doing unicode atom printout with ~w
erl_interface: even more utf8 atom stuff
erts: Fix bug in analyze_utf8 causing faulty latin1 detection
Add UTF-8 node name support for epmd
workaround...
Fix merge conflict with hasse
UTF-8 atom documentation
test case
erl_interface: utf8 atoms continued
Add utf8 atom distribution test cases
atom fixes for NIFs and atom_to_binary
UTF-8 support for distribution
Implement UTF-8 atom support for jinterface
erl_interface: Enable decode of unicode atoms
stdlib: Fix printing of unicode atoms
erts: Change internal representation of atoms to utf8
erts: Refactor rename DFLAG(S)_INTERNAL_TAGS for conformity
Conflicts:
erts/emulator/beam/io.c
OTP-10753
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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.
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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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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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