Message Queues
Input/Output Methods
6-15
6.5 Message Queues
The MSGQ module supports the structured sending and receiving of variable
length messages. This module can be used for homogeneous or
heterogeneous multi-processor messaging. A substantially similar MSGQ
API is implemented in DSP/BIOS Link for certain TI general-purpose
processors (GPPs), particularly those used in OMAP devices.
MSGQ provides more sophisticated messaging than other modules. It is
typically used for complex situations such as multi-processor messaging. The
following are key features of the MSGQ module:
❏
Writers and readers can be relocated to another processor with no
runtime code changes.
❏
Timeouts are allowed when receiving messages.
❏
Readers can determine the writer and reply back.
❏
Receiving a message is deterministic when the timeout is zero.
❏
Sending a message is deterministic (the call, but not the delivery).
❏
Messages can reside on any message queue.
❏
Supports zero-copy transfers.
❏
Can send and receive from HWIs, SWIs and TSKs.
❏
Notification mechanism is specified by application.
❏
Allows QoS (quality of service) on message buffer pools. For example,
using specific buffer pools for specific message queues.
Messages are sent and received via a
message queue
. A reader is a thread
that gets (reads) messages from a message queue. A writer is a thread that
puts (writes) a message to a message queue. Each message queue has one
reader and can have many writers. A thread may read from or write to multiple
message queues.
Figure 6-3.
Writers and Reader of a Message Queue
M SG Q
object
W riter 1
Reader
W riter 2
Summary of Contents for TMS320 Series
Page 1: ...TMS320 DSP BIOS v5 40 User s Guide Literature Number SPRU423G April 2009 ...
Page 16: ...xvi ...
Page 152: ...Tasks 4 48 Figure 4 12 Trace from Example 4 7 ...
Page 168: ...Semaphores 4 64 Figure 4 14 Trace Results from Example 4 11 ...
Page 202: ...5 20 ...
Page 287: ...Index 9 Index Void 1 11 W words data memory 3 15 of code 1 5 wrapper function 2 29 ...
Page 288: ...Index 10 Index ...