Scheduling Operating System Services PhD Planner Research Area: - - PowerPoint PPT Presentation

Scheduling Operating System Services

PhD Planner Research Area: Operating Systems, Distributed Systems

Stefan Bonfert | Ulm University Advisor: Stefan Wesner | Ulm University

Scheduling Operating System Services | Stefan Bonfert Slide 2

What is this about?

• System calls are executed at arbitrary locations and thereby pollute caches and

block shared data structures

• This limits performance of applications since they have to wait for system calls
• System calls can be executed remotely and asynchronously in, e.g.,

Microkernels

• CPU cores can be dedicated to run system calls. This reduces cache pollution

and improves application speed

Scheduling Operating System Services | Stefan Bonfert Slide 3

System Calls

• Interaction Between OS and Application
• Remote Execution in Microkernels
• Advantage:
• Fewer Locking
• Lower Cache Pollution

Scheduling Operating System Services | Stefan Bonfert Slide 3

System Calls

• Interaction Between OS and Application
• Remote Execution in Microkernels
• Advantage:
• Fewer Locking
• Lower Cache Pollution

Application OS

Scheduling Operating System Services | Stefan Bonfert Slide

Application OS Syscall

3

System Calls

• Interaction Between OS and Application
• Remote Execution in Microkernels
• Advantage:
• Fewer Locking
• Lower Cache Pollution

Scheduling Operating System Services | Stefan Bonfert Slide

Application OS Syscall

3

System Calls

• Interaction Between OS and Application
• Remote Execution in Microkernels
• Advantage:
• Fewer Locking
• Lower Cache Pollution

Application OS Syscall OS Delegate

Scheduling Operating System Services | Stefan Bonfert Slide

Application OS Syscall

3

System Calls

• Interaction Between OS and Application
• Remote Execution in Microkernels
• Advantage:
• Fewer Locking
• Lower Cache Pollution

Application OS Pull OS Result

Scheduling Operating System Services | Stefan Bonfert Slide 4

OS Services

• Specific System Call
• Offered by One or Multiple Cores
• Replication:
• Improves Locality
• Synchronisation & Consistency

Scheduling Operating System Services | Stefan Bonfert Slide 4

OS Services

• Specific System Call
• Offered by One or Multiple Cores
• Replication:
• Improves Locality
• Synchronisation & Consistency

Scheduling Operating System Services | Stefan Bonfert Slide 4

OS Services

• Specific System Call
• Offered by One or Multiple Cores
• Replication:
• Improves Locality
• Synchronisation & Consistency

S1 S1 S1 S2 S2 S1 S1 S1 S2 S2

Scheduling Operating System Services | Stefan Bonfert Slide 4

OS Services

• Specific System Call
• Offered by One or Multiple Cores
• Replication:
• Improves Locality
• Synchronisation & Consistency

S1 S1 S1 S2 S2 S1 S1 S1 S2 S2

Scheduling Operating System Services | Stefan Bonfert Slide 5

Scope

• Multi-Node, Multi-Application System
• HPC Applications
• High Concurrency
• Recurring Tasks
• No User Interaction
• Non-Preemptible Execution

Scheduling Operating System Services | Stefan Bonfert Slide 6

Approach

• Monitor System Calls
• Extract Affinities of Tasks to Services
• Cost Model
• Communication to Services
• Replication of Services
• Synchronisation & Consistency
• Location of Input Data
• Resource Utilisation
• Hierarchical Scheduler for Tasks
• Co-Schedule System Services

S1 S2 T1 T2 T3 3 7 1 15

Scheduling Operating System Services | Stefan Bonfert Slide 7

Research Questions

• How does OS service placement affect application performance?
• How do scheduling of application tasks and OS services influence each other?
• What is the optimal placement strategy for OS services to achieve maximum

application performance?

• What is the reconfiguration cost for different OS services?

Scheduling Operating System Services | Stefan Bonfert Slide 8

Questions?