The SawMill Project

1
The SawMill Project

• Jochen Liedtke, Uwe Dannowski, Gerd Liefländer,
  Espen Skoglund
• Universität Karlsruhe, Germany
• Kevin Elphinstone, Trent Jaeger, Yoonho Park,
  Alain Gefflaut, Luke Deller, Volkmar Uhlig
• IBM T. J. Watson, Yorktown Heights, NY

2
Whos Who?

• IBM Watson (Paul Horn, Senior VP)
• Systems (Ambuj Goyal, VP)
• Server Department (Nick Bowen)
• Afpa SawMill (Rich Neves)
• Trent Jaeger
• Yoonho Park
• Kevin Elphinstone
• Alain Gefflaut
• Volkmar Uhlig (Coop, TU Dresden)
• Luke Deller (Coop, UNSW Sydney)

3
Whos Who?

• Universität Karlsruhe
• Fakultät für Informatik
• IBDS
• System Architecture Group
• Jochen Liedtke
• Gerd Liefländer
• Uwe Dannowski (07/99) TU Dresden
• Espen Skoglund (08/99) U Tromsø
• Kevin Elphinstone (03/00) IBM Watson

4
The Multi-Server OS Idea

• Monolithic Unix

apps
apps
apps
apps
OS
Hardware
5
The Multi-Server OS Idea

• Monolithic Unix
• Mach Single-Server Unix

apps
apps
apps
apps
OS
Mikrokernel
Hardware
6
The Multi-Server OS Idea

• Monolithic Unix
• Mach Single-Server Unix
• Mach Multi-Server Unix

apps
apps
apps
apps
file server
process server
memory server
TCP/IP server
Mikrokernel
Hardware
7
The Multi-Server OS Idea

• Monolithic Unix
• Mach Single-Server Unix
• Mach Multi-Server Unix hopes
• coexistence of different
• APIs, file systems
• OS personalities
• flexibility
• extensibility
• simplicity
• maintainability
• security
• safety

apps
apps
apps
apps
file server
process server
memory server
TCP/IP server
Mikrokernel
Hardware
8
The Multi-Server OS Idea

• Monolithic Unix
• Mach Single-Server Unix
• Mach Multi-Server Unix hopes
• coexistence of different
• APIs, file systems
• OS personalities
• flexibility
• extensibility
• simplicity
• maintainability
• security
• safety

apps
apps
apps
apps
Reality unusable
file server
process server
memory server
TCP/IP server
Mikrokernel
Hardware
9
The Multi-Server OS Idea

• Monolithic Unix
• Mach Single-Server Unix
• Mach Multi-Server Unix
• GNU Hurd
• not ready

apps
apps
apps
apps
file server
process server
memory server
TCP/IP server
Mikrokernel
Hardware
10
The Multi-Server OS Idea

• Monolithic Unix
• Mach Single-Server Unix
• Mach Multi-Server Unix
• GNU Hurd
• SawMill Linux

apps
apps
apps
apps
file server
process server
memory server
TCP/IP server
Mikrokernel
Hardware
11
Enable OS ResearchImprove Linux
Rationale

• with Multi-Server and related Nucleus-based
  technology
• Never need to rewrite an entire OS from scratch.
• Even when experimenting with deep OS
  modifications.
• Extend existing OS's with new functionality.
• Customize existing OS's strip them down for
  specific application requirements.

12
Enable OS ResearchImprove Linux
Rationale

• "SawMill" Multi-Server Linux
• (1) isolate Linux services from each other(2)
  improve them one by one
• VM, scheduling, security (denial of service),
  reliability, SMP, large memory, mmap, async io,
  select, large files
• Extend Linux, add value
• Afpa, new security policies.
• Customize Linux for special devices.

13
A Research Road
Rationale
UKa

• for microkernel-based system construction
• multi-server Linux, composable OS
• middleware, customized servers, applications
• mastering complexity in OS construction
• for microkernel evolution
• L4, Merced, embedded
• for pervasive systems

14
Business ImpactResearch Impact
IBM

• Business units support SawMill-derived and
  specialized systems.
• Toolkit for pervasive devices

15
Business ImpactResearch Impact
IBM
UKa

• Generic Methodology and Technology
  forconstructing highly-configurable and
  composable OS's.
• Generic MT for managing and controlling the
  exploding complexity in OS's.
• Strategy Explore the Multi-Server approach,
  "SawMill" Linux.
• Strategy Develop generic OS and middleware
  components.
• Strategy Develop highly-configurable OS's for a
  wide variety of devices from wristwatches
  to superservers.

16
SawMill Linux
Nucleus
17
Current State of SawMill Linux

• Basic components
• Task server, memory server
• Loader, VM framework
• Glue SawMill Flick
• L4 X Nucleus
• Linux 2.2 - multithreaded kernel
• L4 X / Linux 2.2 development environment

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BeginningNearly a Single Server
Nucleus
19
First Driver File System out of Linux
Nucleus
20
VM Framework

• VM Framework

• Dataspace managers "Memory providers"
• Anon DM Initial dataspace manager
• ELF decoder
• Region map - not shown
• Forwards page faults to DMs
• One per task currently
• Region map manager

21
ELF Decoder / Loader

• Provides program segments as dataspaces
• Linux task provides executable file

22
First Driver File System out of Linux
Nucleus
23
More components out of Linux new services
Nucleus
24
Ausgewählte Diplom- und Studienarbeiten

• SawMill Core
• Analysis of Linuxs VM system
• An improved basic VM for SawMill Linux
• A SawMill wrapper for Linux drivers
• Selected Native SawMill drivers
• Experimental SawMill schedulers
• Adaptive Multi-OS memory management
• File Systems
• LFS as a SawMill Dataspace Manager
• A persistent-memory manager (disk based)
• A persistent-memory manager (a la Rio)
• A lazy-copying dataspace manager
• Network Stack
• SawMill adaptation of Linuxs TCP/IP stack
• A native SawMill TCP/IP stack implementation
• User-level pinning for SawMill pagers
• A SawMill TCP/IP stack using pinning
• Benchmarking Analysis
• AIM benchmarking and analyzing SawMill Linux

25
Ausgewählte Diplom- und Studienarbeiten

• IA-64 (Merced)
• Feasibility study L4 on Merced
• A Merced testbed for microkernel development
• An experimental microkernel for Merced
• IA-32 (x86)
• Design and Implementation x86-SMP L4
• Adapting and optimizing L4 for Pentium III
• L4 Version 4
• Debugging, testing and benchmarking
• L4 Auto Tester
• New implementation of L4s kernel debugger L4KD
• Integrating gdb and L4KD
• An extended L4 microbenchmark set
• Miscellaneous
• New L4 language bindings
• Flick IDL compiler optimized code generation for
  L4/SawMill

26
Next

• 8.7. - 13.7.
• Rich Neves, Kevin Elphinstone, Trent Jaeger,
  Yoonho Park in Karlsruhe
• 8.7. Informatik Sonderkolloquium
• Rich Neves
• Kernel Extensions for High-Performance Servers

27
Contact

• Jochen Liedtke,
• Room 158
• Tel 4053
• liedtke_at_ira.uka.de
• http//i30www.ira.uka.de
• http/i30www.ira.uka.de/SawMill