Causeway: Operating System Support For Controlling And Analyzing The Execution Of Distributed Progra

1
Causeway Operating System Support For
Controlling And Analyzing TheExecution Of
Distributed Programs

• Anupam Chanda, Khaled Elmeleegy, and Alan L. Cox
• Department of Computer Science
• Rice University, Houston, Texas 77005, USA
• Willy Zwaenepoel
• School of Computer and Communication Sciences
• EPFL, Lausanne, Switzerland

2
Metadata

• meta-applications Resource scheduling and
  performance debugging, e.g.
• Metadata priority of a task, e.g.

3
What is Causeway

• Causeway operating system support facilitating
  development of meta- applications, like priority
  scheduling and performance debugging, to control
  and analyze distributed programs.

4
What is Causeway

• Provide operating system support for metadata
  injection and access, and automatic propagation
• meta-applications can be implemented on top of
  Causeway
• (identifier, type, value, propagation bit mask,
  merge routine identifier)
• merge routine identifier--min, max, etc.

5
Components of Causeway

• Interfaces for actors to inject and access
  metadata
• Automatic propagation of metadata to and from
  actors across channels

6
How Causeway works

• Metadata is assigned to an actor when it performs
  injection. Later, when it writes to a channel,
  its metadata is associated to the data written.
  On subsequent read on the channel by another (or
  the same) actor, metadata is propagated from the
  data to the actor performing the read.

7
Interfaces

• Actor Interface
• injection, inspection, modification and removal
  of metadata
• user-level or kernel-level
• cwa_type_query, cwa_data_lookup, cwa_data_insert,
  cwa_data_remove
• Callback Interface
• register a transfer-point callback method

8
Automatic Propagation of Metadata

• Assigning Metadata to an Actor
• Injection
• Propagation
• Different identifiers
• Same identifier

9
Automatic Propagation of Metadata

• Propagation across Channels
• Pipes
• Sockets
• A challenge and its solution

10
Need for the Framework

• System support, not application support
• Application-level propagation will involve
  augmenting applications and communication
  protocols
• some individual components are unaware about the
  presence of metadata or ignore it.

11
Use of Causeway

• a multi-tier priority enforcement system
• prioritize requests in a multi-tiered web
  services application
• priority as metadata
• tested this system with the TPC-W benchmark

12
Future work and Conclusions

• Future work
• Files
• Shared Memory
• Conclusions