From 19c4689eea86f26c5af9b8f712c227ce4f62310b Mon Sep 17 00:00:00 2001 From: Rickard Green Date: Tue, 24 Nov 2015 15:57:55 +0100 Subject: Replace off_heap_message_queue option with message_queue_data option The message_queue_data option can have the values - off_heap - on_heap - mixed --- erts/doc/src/erlang.xml | 94 +++++++++++++++++++++++++++++++------------------ 1 file changed, 60 insertions(+), 34 deletions(-) (limited to 'erts/doc/src/erlang.xml') diff --git a/erts/doc/src/erlang.xml b/erts/doc/src/erlang.xml index 2e82bb62a9..6ed03f3dfc 100644 --- a/erts/doc/src/erlang.xml +++ b/erts/doc/src/erlang.xml @@ -58,6 +58,12 @@ + + +

See erlang:process_flag(message_queue_data, MQD).

+ + +

See erlang:timestamp/0.

@@ -4280,39 +4286,52 @@ os_prompt%

Returns the old value of the flag.

 - + - Set process flag off_heap_message_queue for the calling process + Set process flag message_queue_data for the calling process +

This flag determines how messages in the message queue are stored. When the flag is:

- true + off_heap

All messages in the message queue will be stored outside of the process heap. This implies that no messages in the message queue will be part of a garbage collection of the process.

- false + on_heap +

+ All messages in the message queue will eventually be + placed on heap. They may however temporarily be stored + off heap. This is how messages always have been stored + up until ERTS version 8.0. +

+ mixed

Messages may be placed either on the heap or outside of the heap.

+

+ The default message_queue_data process flag is determined + by the +xmqd + erl command line argument. +

If the process potentially may get a hugh amount of messages, - you are recommended to set the flag to true. This since - a garbage collection with lots of messages placed on the heap - may become extremly expensive. Performance of the actual - message passing is however generally better when setting the - flag to false. + you are recommended to set the flag to off_heap. This + since a garbage collection with lots of messages placed on + the heap may become extremly expensive and the process may + consume large amounts of memory. Performance of the + actual message passing is however generally better when not + using the off_heap flag.

- When changing this flag from false to true, - all messages in the message queue are moved off heap. This - work has been initiated but not completed when this function + When changing this flag messages will be moved. This work + has been initiated but not completed when this function call returns.

Returns the old value of the flag.

@@ -4478,6 +4497,7 @@ os_prompt% +

Returns a list containing InfoTuples with miscellaneous information about the process identified by @@ -4530,6 +4550,7 @@ os_prompt% +

Returns information about the process identified by Pid, as specified by @@ -4698,13 +4719,14 @@ os_prompt% monitor by name, the list item is {process, {RegName, Node}}.

- {off_heap_message_queue, OHMQ} + {message_queue_data, MQD} -

Returns the current state of the off_heap_message_queue - process flag. OHMQ is either true, or - false. For more information, see the documentation of - process_flag(off_heap_message_queue, - OHMQ).

+

Returns the current state of the message_queue_data + process flag. MQD is either off_heap, + on_heap, or mixed. For more information, see the + documentation of + process_flag(message_queue_data, + MQD).

 {priority, Level} @@ -5474,6 +5496,7 @@ true Creates a new process with a fun as entry point. +

Returns the process identifier (pid) of a new process @@ -5490,6 +5513,7 @@ true Creates a new process with a fun as entry point on a given node. +

Returns the process identifier (pid) of a new process started @@ -5505,6 +5529,7 @@ true Creates a new process with a function as entry point. +

Works as @@ -5607,17 +5632,17 @@ true fine-tuning an application and to measure the execution time with various VSize values.

 - {off_heap_message_queue, OHMQ} + {message_queue_data, MQD} -

Sets the state of the off_heap_message_queue process - flag. OHMQ should be either true, or - false. The default off_heap_message_queue process - flag is determined by the - +xohmq erl +

Sets the state of the message_queue_data process + flag. MQD should be either off_heap, + on_heap, or mixed. The default + message_queue_data process flag is determined by the + +xmqd erl command line argument. For more information, see the documentation of - process_flag(off_heap_message_queue, - OHMQ).

+ process_flag(message_queue_data, + MQD).

 @@ -5627,6 +5652,7 @@ true Creates a new process with a function as entry point on a given node. +

Returns the process identifier (pid) of a new process started @@ -7106,15 +7132,15 @@ ok used by the runtime system. It is on the form "<major ver>.<minor ver>".

- off_heap_message_queue + message_queue_data -

Returns the default value of the off_heap_message_queue - process flag which is either true or false. This - default is set by the erl command line argument - +xohmq. For more information on the - off_heap_message_queue process flag, see documentation of - process_flag(off_heap_message_queue, - OHMQ).

+

Returns the default value of the message_queue_data + process flag which is either off_heap, on_heap, or mixed. + This default is set by the erl command line argument + +xmqd. For more information on the + message_queue_data process flag, see documentation of + process_flag(message_queue_data, + MQD).

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