Snowbird: Interactive Resource-Intensive Applications Made Easy

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SnowbirdInteractive Resource-IntensiveApplicati
ons Made Easy

• H. Andrés Lagar-Cavilla
• Niraj Tolia , Eyal de Lara,
• M. Satyanarayanan Dave OHallaron
• University of Toronto, HP Labs,
• Carnegie Mellon University
• Middleware, November 2007

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Bimodal Applications

• Interactive
• Cognitive phase
• Resource-Intensive
• Crunch phase
• Digital Animation
• Scientific Computing
• Engineering Design
• Bio/Pharma
• Video Editing
• .

Maya (digital animation)
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Dichotomy

• Crunch (computation)
• Short completion time
• Remote computing resources
• Cognitive (interaction)
• Crisp interactive performance
• User attention

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Execution Alternatives

• Thick Clients (Desktop PCs)
• Cognitive excellent interactive performance
• Crunch resource constrained
• Thin Clients (VNC, Remote Desktop)
• Crunch use of remote resources (CPU, Data)
• Cognitive latency and jitter impact
  interactions
• Custom Applications
• Pipeline placement over different nodes
• Requires significant developer resources

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Execution Alternatives

• Cognitive excellent interactive performance
• Crunch use of remote resources (CPU, Data)

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Snowbird Agent Abstraction

• Applications encapsulated within an agent
• Agent processes, libraries, IPC, OS, config
  data
• Migration performance goals achieved by morphing
  
• a thin client for resource intensive crunch
  phases
• a thick client for highly interactive cognitive
  phases

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Bimodal Applications Made Easy

• Develop apps as monolithic blocks
• Dont worry about what executes where
• Agent is migrated to satisfy each phase
• Seamless and transparent behavior
• Legacy support
• Different OSs (and versions/features)
• Different languages (Fortran!)
• No need for recompilation, relinking, etc
• Closed source apps just work

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Implementation
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Design Criteria

• VM-based migration
• x86 interface most widely deployed
• Transparently support OS, lang, etc
• Internet scale
• WAN migration
• Long fat pipes 50 Mbp/s, 50-200 ms RTT
• Use of graphics HW acceleration a must
• For the cognitive mode of bimodal apps
• Server-less design (P2P)
• All hosts symmetric
• Can execute anywhere

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Components

• VMM suspend, resume, live migration
• Xen 3.0.1
• Interaction-aware migration manager
• Transparent
• Support for 3D acceleration in VMs
• Vital for crisp interaction
• Virtual disk that maximizes locality
• WAN area migration

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Agent Profiles Migration Manager

• FSM that models an agents behavior
• Provided by expert users, admins, or developers
• Default system-wide profile available
• Only deployment additional effort

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Interaction-aware

• Novelty in our approach
• Measure the quality of the interactive response
• We use frames per seconds
• More in sync with operations in bimodal apps
• Stretch object, rotate, zoom, etc
• Pure latency not enough
• Ample space for future work

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Frames Per Second

• Local FPS n/latency

• Non work-conserving (VNC) FPS 2/latency

• Work-conserving (X) FPS n/(latencyk)

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The Rest

• VMGL support for 3D acceleration in VMs
• Coming live to this conference in 5 mins
• Follow up VEE 2007, gt4K downloads
• WANDisk virtual disk maximizes locality
• Minimizes WAN communication
• Simplifies state synchronization
• More details in paper

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Evaluation
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Benchmarks

• Broad set of domains
• Scientific Computing, Bio, Video Editing,
  Animation
• Closed and open source
• Straightforward installation
• Able to use generic profile on all four
• Partitioned mode for comparison
• ADF Maya

QuakeViz
Kmenc15
Maya (closed source)
ADF (closed source)
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Methodology

• Crunch cognitive benchmarks
• Performing crunch experiments is easy
• Replaying long interactive traces is not
• Cant expect a user to do it
• Must be able to compare results
• VNC-Redux record and replay interactive user
  sessions
• Record input and screen state
• This is matched during replay for accuracy

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Experimental Setup
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Results Crunch Phase
370Ouch!

• Snowbirds crunch performance
• Much better than thick
• Comparable to thin/partitioned

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Results Cognitive Phase

• Better interactivity than thin clients
• Is Snowbird any worse than a thick client?
• gt 20 FPS is ok, lt 8 FPS is unusable

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Take Home Messages

• Bimodal applications
• What they are and why they matter
• Thin clients are not almighty
• There is no replacement for local interaction
• Best of both worlds thick and thin clients
• Necessary in an Internet world with remote
  computing resources
• VM-based app migration is feasible
• And with many advantages
• Future trends align well

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Futurism

• More bandwidth cheaper VM migration
• What about latency?
• The earth is not shrinking
• Speed of light is not increasing
• More routers, overlays, firewalls
• Toronto-London UK 109ms
• Toronto-LA 84ms
• Insurmountable obstacle for thin clients

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Questions?
Thanks ?
H. Andrés Lagar-Cavilla andreslc_at_cs.toronto.edu N
iraj Tolia, Eyal de Lara, Satya Dave
OHallaron U of Toronto, HP Labs, Carnegie Mellon
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Backup
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VMGL 3D Acceleration in VMs

• OpenGL virtualization
• Hardware specs closed, unavailable
• Focus instead on software standards
• OpenGL -gt cross-platform
• Direct3D -gt MS-only
• Intercept GL calls and forward them to the host.
  Proprietary driver renders there.
• More details VEE 2007

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Open GL for X11 Apps
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VMGL for X11 Apps
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WANDisk Virtual Disk
Chunk Table
foo.toronto.edu
ChunkMisses
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Why Another Storage System?

• Exploits Snowbird characteristics
• P2P model
• No server interposition
• Single-writer simple metadata, no locks
• Minimizes WAN talk
• Locality persistent replicas
• Differential transfers rsync
• On-demand fetching

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Experimental Setup

• Thick No virtualization, on User Desktop
• User Desktop UP with graphics acceleration
• Thin No virtualization, on Compute Server
• Compute Server 4-way SMP
• 100 Mbit/s WAN, RTT 33, 66, and 100 ms
• Partitioned
• App-specific developer-brewed Maya ADF
• Snowbird
• Agents are initially launched on User Desktop

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ADF Migration Time (secs)
Latency (ms) Detection Migration Pause
33 12.5 62 4.9
66 11.5 62 6.2
100 13.1 64.9 6.7
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Applicability of Snowbird

• Morphing time our implementation
• Speedup application resources
• C Crunch phase time locally

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Snowbird Limitations

• Parallelism up to SMP level
• What about cluster-scale?
• SSE, 3DNow!
• i.e. x86 is not that uniform
• Overlapping phases
• Hysteresis, priority in migration manager
• Very short phases
• Cost/benefit analysis

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Our Current Interests

• VM support for large parallel tasks
• Relevant to commodity computing
• Migration, the cloud, etc
• How to measure interactive performance
• Thin clients, desktop consolidation, VMs
• Unknown effects for modern (3D-heavy) GUIs

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Really Backup Backup
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Keywords Of This Presentation

• Thin clients
• Remote execution
• Interactive Performance
• Thick clients
• Virtual machine migration
• Application migration
• Bimodal applications
• What they are and why they matter

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Frames Per Second

• Local FPS frames/latency

• Non work-conserving same latency, less frames

• Work-conserving same frames, more latency

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What We Need

• System support for bimodal applications
• Combine best of both worlds
• Thick client, local execution
• Interaction
• Thin client, remote execution
• Computation
• Make development easy

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Results Crunch Phase

• Snowbirds crunch performance
• Much better than thick
• Comparable to thin/partitioned

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Talk Pointers

• Be more explicit demo thin, frames
• Proxy FPS input in migr manager