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| author | Sebastian Huber <sebastian.huber@embedded-brains.de> | 2015-04-30 13:12:54 +0200 |
|---|---|---|
| committer | Sebastian Huber <sebastian.huber@embedded-brains.de> | 2015-05-19 12:00:46 +0200 |
| commit | cc18d7bec7b3c5515cb9e6cd9771d4b94309b3bd (patch) | |
| tree | 59fd8c8ca70830762e632e255a2078f22ac6a821 /doc/user/msg.t | |
| parent | score: Delete _CORE_message_queue_Flush_support() (diff) | |
| download | rtems-cc18d7bec7b3c5515cb9e6cd9771d4b94309b3bd.tar.bz2 | |
score: Fine grained locking for message queues
Aggregate several critical sections into a bigger one. Sending and
receiving messages is now protected by an ISR lock. Thread dispatching
is only disabled in case a blocking operation is necessary. The message
copy procedure is done inside the critical section (interrupts
disabled). Thus this change may have a negative impact on the interrupt
latency in case very large messages are transferred.
Update #2273.
Diffstat (limited to '')
| -rw-r--r-- | doc/user/msg.t | 5 |
1 files changed, 4 insertions, 1 deletions
diff --git a/doc/user/msg.t b/doc/user/msg.t index f58d677150..eb3cb3561a 100644 --- a/doc/user/msg.t +++ b/doc/user/msg.t @@ -50,7 +50,10 @@ wait for a message to arrive at a queue. Also, a task may poll a queue for the arrival of a message. The maximum length message which can be sent is set -on a per message queue basis. +on a per message queue basis. The message content must be copied in general +to/from an internal buffer of the message queue or directly to a peer in +certain cases. This copy operation is performed with interrupts disabled. So +it is advisable to keep the messages as short as possible. @subsection Building a Message Queue Attribute Set |