Loading in 5 sec....

Lamport’s Scalar ClocksPowerPoint Presentation

Lamport’s Scalar Clocks

- By
**madra** - Follow User

- 113 Views
- Uploaded on

Download Presentation
## PowerPoint Slideshow about ' Lamport’s Scalar Clocks' - madra

**An Image/Link below is provided (as is) to download presentation**

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.

- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -

Presentation Transcript

### Lamport’s Scalar Clocks

Shiva Bottu

Organization

Introduction

High level Implementation Details

Experimentation

Results

Further Research

Introduction

Lamport’s logical clocks are introduced to capture causality relation in a distributed system.

Each process Pi has a logical clock Ci and for a particular event a in P, it assigns an integer value Ci, which is timestamp of the event.

Timestamps are monotonically increasing.

High level Implementation Details

- There are 2 implementation rules that should be followed
- Before executing event, update timestamp value
Ci:=Ci+d

- When sending a message, attach the timestamp. When message is received by a process, timestamp of receive event is calculated as maximum of the two timestamps (timestamp of the process and timestamp received in the message)
Ci:=max(Ci,Cmsg)

Experimentation

- Number of processes are varied.
- Random flood algorithm is used to exchange messages between processes
- Part 1:
- Total number of updates are plotted against number of processes
- Average number of updates per process against number of processes

- Part 2:
- Number of updates and Number of messages against number of processes
- Number of processes against average number of messages required for each process

Part 1(a):Total clock updates against Number of processes

Number of clock updates

Number of Processes

Part 1(b):Average clock updates per process against Number of processes

Average clock updates

Number of Processes

Part 2(a): No. of Processes VS clock updates & No. of Processes VS No. of messages required

clock updates & Messages

Number of Processes

Part 2(b): No. of Processes VS Average no. of messages per process

No. of Messages per process

Number of Processes

Results

From part-1(a), it is observed that the number of updates increase with increase in number of processes

From part-1(b), average number of updates per process increase with increase in number of processes

From part-2(a), we can observe that number of clock updates and number of messages increase with increase in no. of processes

From part-2(b), we can observe that average number of messages required per process increases with increase in number of processes

Further Research

To change the base algorithm from random flood to other topologies and test with the same process.

Running with high load of processes.

References

http://en.wikipedia.org/wiki/Lamport_timestamps

http://cnlab.kaist.ac.kr/~ikjun/data/Course_work/CS642-Distributed_Systems/papers/lamport1978.pdf

Download Presentation

Connecting to Server..