Hi,
Some very simple measurements on processing time (not on latency time) by using a H.263 decoder (tmndec) applied to an H.263 encoded file (51 H.263 frames).
For stressing the system, I've used stress tool: http://weather.ou.edu/~apw/projects/stress/
With standard Linux kernel for PowerPC/Xilinx (version 2.6.35):
Without CPU loading:
# cat godec
./tmndec -o5 stream.263 miss_dec.qcif
/bin # ./godec
0.63 seconds, 51 frames, 80.95 fps
With CPU loading:
/bin # stress -i 20 -c 20 &
/bin # stress: info: [799] dispatching hogs: 20 cpu, 20 io, 0 vm, 0 hdd
/bin # ./godec
17.57 seconds, 51 frames, 2.90 fps
With Xenomai Linux kernel for PowerPC/Xilinx (version 2.6.35 with Xenomai):
Without CPU loading:
/bin # ./godec
0.65 seconds, 51 frames, 78.46 fps
With CPU loading:
/bin # stress -i 20 -c 20 &
/bin # stress: info: [799] dispatching hogs: 20 cpu, 20 io, 0 vm, 0 hdd
/bin # ./godec
19.20 seconds, 51 frames, 2.66 fps
Program executed as a POSIX RT thread with sched tool (SCHED_FIFO scheduling used by Xenomai for POSIX RT threads http://xenomai.org/index.php/Porting_POSIX_applications_to_Xenomai#Real-time_priorities):
/bin # sched -f 99 ./godec
0.65 seconds, 51 frames, 78.46 fps
With Xenomai extension, processing time for decoder as a Xenomai RT thread (SCHED_FIFO, priority 99) is bounded even with CPU loading...
Pat.
