Design Space Exploration for Run-Time Management of a Reconfigurable System for Video Streaming - Multi-objective Design Space Exploration of Multiprocessor SoC Architectures - page 201

3.5 250

3

200

2.5

2 150

1.5

100

1

0.5 50

30 35 40 45 50 55 60 65 70 30 35 40 45 50 55 60 65 70

a

Time [seconds] Time [seconds]

3.5 250

3

200

2.5

2 150

1.5

100

1

0.5 50

30 35 40 45 50 55 60 65 70 30 35 40 45 50 55 60 65 70

b Time [seconds] Time [seconds]

3.5 250

3

200

2.5

2 150

1.5

100

1

0.5 50

30 35 40 45 50 55 60 65 70 30 35 40 45 50 55 60 65 70

c

Time [seconds] Time [seconds]

Fig. 9.7 Resource allocation and average operating frequency for the three MPEG4 instances.
a Left camera, b Center camera, c Right camera

As the car speed increases, the frame rate requirements for the lateral cameras
increase faster than the requirement for the central camera (Fig. 9.6 ). This brings
around the 40th second to a situation where all requirements can still be met reducing
the resources for the central camera while providing three cores to each lateral camera.
This situation stands until the requirements cannot be met anymore. In this last
situation, the requirement of the lowest priority application, i.e., the MPEG4 encoder
of the right camera, is relaxed and only one resource is assigned to it. This situation
is also visible in Fig. 9.8 b, where the right camera frame rate is lower than the QoS
requirement by around 4 fps (QoS penalty of − 4 fps ).