1. Java Jitters -- The Effects of Java on Jitter in a Continuous Media Stream
Mark Claypool and Jonathan Tanner
Computer Science Department
Worcester Polytechnic Institute

2. Motivation Java J a v Continuous Media Continuous Media Work
Entertainment
Java
Cross platform
Dynamic
Security
Java Media API J a v
Continuous Media

3. Java Runtime Java Source Bytecode JIT Compiler Static Native Compiler
JVM
Java OS
Native OS
General CPU
Java CPU

4. Java Run-Time Overhead
Bytecode
Execution
Garbage
Collection
Thread
Synch.
Misc
15%
55%
15%
15%

5. Java Performance Traditional benchmarks CaffeineMark
Spec95
jBYTEmark
CaffeineMark
JIT and Static Native speedup
But … Continuous Media?

6. Continuous Media Quality
time
Server S0 S1 S2 S3 S4 t0
Client t0 C0 C1 C2 C3
Data
Loss
Delay
Jitter

7. Garbage Collection
GC frees memory
Low Memory.
Begin GC

8. Experiments Capture Format Send Interpreted - Sun’s JVM
Static Native Compiled - Toba
Baseline - C++ (with g++)

9. Experiments Frame Rate: 3 - 30 fps Capture Frame Size: 4 - 76k
Format: min - max
Send Frame Size: k
166 MHz Intel Pentium
32 MB RAM
Linux
Ethernet

10. Jitter

11. Frame Rates

12. Conclusions Java 1/3 full-motion video
could do up to 2/3
Static Native Compilation has same jitter and frame rate as Interpreted Java
C++ vastly superior in framerate and jitter
Contributions:
Experimental continuous media performance
Tunable continuous media server benchmark

13. Future Work Client Benchmark Just-In-Time (JIT) Compilers
Adaptive Compilers
Operating Systems
Java OS
Browsers
Continuous Media Quality