January 16th,20061 Performance Engineering of Distributed Systems and Wireless Networks Varsha Apte, CSE Dept., IIT Bombay Collaborators: Profs Bellur,

January 16th,2006 1

Performance Engineering of Distributed Systems and Wireless Networks

Varsha Apte, CSE Dept., IIT BombayCollaborators: Profs Bellur, Iyer (KreSIT), Manjunath (EE)

UNSW Workshop

January 16th, 2006

January 16th,2006 2

Ongoing Research

Two threads of work Distributed Systems Performance Wireless Networks (mainly 802.11

family of LANs)

At the core: Performance point of view, using models or measurement.

January 16th,2006 3

Distributed Systems: Context

Internet (Multi-tiered, heterogeneous, geographically

distributed,Web front-end)

End Users

Server System

Multiple Use cases

QoS expectation

sData center cost

optimization

January 16th,2006 4

High-level performance analysis tools

Goal: To go from here:

User Web Auth IMAP

login/passwdis valid

invalidre-login

validdisplay inbox messages

list of messagesInbox listing

0.1

0.9

Sync

+auth

web

web

imap

smtp

imap

auth

LAN 1LAN 2

Physical server 1

Physical server 2

Physical server 3Network delay

+ resource profiles + workload profile

January 16th,2006 5

High-level performance analysis tools

To here:

Tool does transformation to queuing network

and its analysis[6]. (Both Simulation

and Analytical Engine)

January 16th,2006 6

Related Research

Tool for generating resource consumption profile (Auto profiler)

Tool for generating message sequence charts (Prof. Umesh Bellur)

Both are inputs required in the performance analysis tool

January 16th,2006 7

Generate Load

ProfileServers

1 2

3Collect clientstatistics Collect server

statistics

Client

Correlate & display

Autoprofiler

M

S

S

S

S

• Master – Slave Architecture

• Slaves profiles the servers.

• Master co-ordinates the process.

Autoprofiler [1]Servers

January 16th,2006 8

Overload/Admission Control of Distributed Systems

Goal: To develop self-tuning, self-configuring control that can guarantee QoS levels to users of software services

Preliminary results: Using LIFO queuing discipline in a Web-server at overload. w/ Prof. D. Manjunath [2]

January 16th,2006 9

Wireless LANs

Capacity, performance (802.11b) Admission control (801.11e) Location Determination (802.11b)

January 16th,2006 10

Sizing Methodology for 802.11b WLANS

n*

n* : Number of users that should be in “one LAN”

Sizing algorithm using analytical models [4]

January 16th,2006 11

Admission Control in 802.11e WLANS

PLUS-DAC: Priority, Load, Utilization based Scheme for Distributed Admission Control, w/Prof. Sridhar Iyer [3]

January 16th,2006 12

Location Determination using WLANs

Goal: to improve on accuracy of existing WLAN based location determination systems

Improvement using multiple observers technique [5]

January 16th,2006 13

Future Directions

Distributed Systems

•Continue Tool Development (w/ Prof. Umesh Bellur) for Performance analysis of distributed systems extend to model details of J2EE systems

•Software QoS in Shared Hosting Centers – self tuning mechanisms

Wireless Networks

•Protocols and their analysis for mesh networks

•QoS in Wireless LANs – measurements on real testbeds

•Location Determination: develop applications

January 16th,2006 14

References

1. B. Nagaprabhanjan and Varsha Apte, “ A tool for automated resource consumption profiling of distributed transactions ”, in Lecture Notes in Computer Science, Springer-Verlag - Proceedings of the International Conference on Distributed Computing and Internet Technology (ICDCIT), Bhubaneshwar, India, December 2005.

2. "A Combined LIFO-Priority Scheme for Overload Control of E-commerce Web Servers" , Naresh Singhmar, Vipul Mathur, Varsha Apte and D. Manjunath, Proceedings of the International Infrastructure Survivability Workshop (affiliated with the 25th IEEE International Real-Time Systems Symposium), Lisbon, Portugal, 2004.

3. Kiran K. Gavini, Varsha Apte, Sridhar Iyer, “PLUS-DAC: A Distributed Admission Control scheme for IEEE 802.11e WLANs“, in the Proceedings of the International Conference on Networking (ICON), Kuala-Lumpur, Malaysia, November 2005.

4. Preetam Patil and Varsha Apte, “Sizing of 802.11 Wireless LANs”, in the Proceedings of the ACM Workshop on Mobile Applications and Services in Hotspots (WMASH), Cologne, Germany, September, 2005.

5. Raman Kumar K, Varsha Apte and Yogesh Powar, “Improving the accuracy of WLAN based location determination systems using Kalman filter and multiple observers”, to appear in WCNC 2006, Las Vegas, USA.

6. Rukma P. Verlekar, Varsha Apte, “A Methodology and Tool for Performance Analysis of Distributed Systems”, to appear in the Emerging Research Track of the International Conference on Software Engineering, Shanghai, China, May 2006.