Changes between Version 12 and Version 13 of user_applications

Timestamp:

Nov 20, 2015, 4:24:38 PM (10 years ago)

Author:

alain

Comment:

--

user_applications

@@ -169 +169 @@
  * The N-2 compute() threads running on all other processors are  continuously reading token  from the local input channel, and writing the same token to the local output channel, after a random delay emulating a variable processing time. They use blocking access functions.
 
-It require one TTY terminal shared by all threads.
+It requires one TTY terminal shared by all threads.
  
 The source code can be found [source:soft/giet_vm/applications/router/router.c here], and the mapping is defined [source:soft/giet_vm/applications/router/router.py here].
+
+== __mjpeg__ ==
+
+This multi-threaded application makes the decompression of a MJPEG bit-stream contained in a file.
+It illustrates the "pipe-line" parallelism, and the message passing programming model, on top of the POSIX threads API, and the MWMR channels API.
+The application is described as a TCG (Task and Communication Graph), and all communications between threads uses MWMR channels.
+Each pipeline decompress one complete image, and there is one pipe-line per cluster.
+It uses the chained buffer DMA component to display the stream of decompressed images on the graphic display.
+It contains 6 types of threads (plus the "main" thread, that makes initialisation), and 7 types of MWMR communication channels:
+ * the TG thread dispatch the bit-stream to the pipeline. It is only mapped in cluster[0,0].
+ * the 5 threads implementing the pipeline (DEMUX, VLD, IQZZ, IDCT, LIBU) are replicated in all clusters.
+ * the 7 MWMR channels are replicated in all clusters.
+
+The hardware constraints are the following
+ * The number of clusters cannot be larger than 16*16.
+ * The number of processors per cluster is not constrained.
+ * The frame buffer size must fit the decompressed images size.
+ * It uses one TTY terminal shared by all tasks.
+
+The source code can be found [source:soft/giet_vm/applications/mjpeg/mjpeg.c here], and the mapping is defined [source:soft/giet_vm/applications/mjpeg/mjpeg.py here].