ESMF Design Overview and Implementation Strategy

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ESMF Design Overview andImplementation Strategy

MITgcm
NASA GSFC PSAS
NCEP Forecast
GFDL FMS Suite
Cecelia DeLuca / NCAR2nd ESMF Community
MeetingPrinceton, NJ
NSIPP Seasonal Forecast
NCAR/LANL CCSM
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Outline

• ESMF Design Goals
• ESMF Design Strategies
• Architecture and Features
• Implementation Strategy

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ESMF Design Goals

• Composable, swappable, nestable model components
  for building Earth system applications

hurr_sim
ocean
assim_atm
assim
atm
dyn
phys
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ESMF Design Goals (cont.)

• Reusable toolkits for grid operations and routine
  utilities
• Performance portability and ease of use in a
  complex, transient computing environment
• Application and infrastructure codes that are
  maintainable and extensible

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ESMF Design Goals (cont.)

• Flexibility
• To allow unconstrained scientific development
• To encourage technical innovation
• To support partial adoption of framework services
• To accommodate different programming models

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Outline

• ESMF Design Goals
• ESMF Design Strategies
• Architecture and Features
• Implementation Strategy

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Architecture
Composable, swappable, nestable model components
for building Earth system applications Reusable
toolkits for grid operations and routine
utilities Performance portability and ease of
use in a complex, transient computing environment
Coupling Layer
ESMF Superstructure
Model Layer
User Code
Fields and Grids Layer
ESMF Infrastructure
Low Level Utilities
External Libraries
BLAS, MPI, NetCDF,
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ESMF Design Approach
Application and infrastructure codes that are
maintainable and extensible

• Component-based architecture large, functionally
  related pieces of software (e.g., atmosphere,
  land models) interact through well-defined
  interfaces
• Object oriented design smaller, functionally
  related pieces of software are bundled into
  modules containing data and methods
• Layered design details of platform and
  parallelism are not visible at the highest level
  interfaces

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ESMF Design Approach (cont.)

• Flexibility
• To allow unconstrained scientific development
• To encourage technical innovation
• To support partial adoption of framework services
• To accommodate different programming models

• Physical interfaces to components are not
  prescribed
• Designed to be compatible with user-managed
  intra-component communication
• Extensible for new grids / algorithms / comm
  libraries
• Many ESMF services may be used independently
• Allows arbitrary placement of inter-component
  communication

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Outline

• ESMF Design Goals
• ESMF Design Strategies
• Architecture and Features
• Implementation Strategy

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General Features

• ESMF will be usable by models written in
  F90/C/C
• ESMF will be usable by models requiring adjoint
  capability
• ESMF will be usable by models requiring shared or
  distributed memory parallelism semantics
• ESMF will support sequential and concurrent modes
  of execution
• ESMF will support several I/O formats, including
  GRIB/BUFR, netCDF, HDF
• ESMF will have uniform syntax across platforms
• ESMF will target a broad range of platforms, from
  major centers ? commodity hardware

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ESMF Services
components (gridded, coupler, app)states
Components / Coupling
field metadatafield and field bundle datafield
I/O
Fields
Fields and Grids
grid metadatagrid decomposition
Grids
transpose, halo, etc.abstract machine layout
Parallel Utilities
event alarmsperformance profilingI/O
primitivescommunication primitives, etc.
Low-Level Utilities
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ESMF Components

• ESMF provides an environment for assembling
  geophysical components into an application.

Application Component
Gridded Components
Coupler Components

• ESMF provides a toolkit that components use to
• increase interoperability
• improve performance portability
• abstract common services

Component Init( ), Run( ), Checkpoint( )
Field Halo( ), Import( ), Export( ) I/O
Grid Regrid( ), Transpose( ) Metrics
DELayout, PE List, Machine Model
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ESMF Version 1.0
ApplicationComponent
GriddedComponent
CouplerComponent
Superstructure
State
Infrastructure
Bundle
Regrid
Field
Grid
PhysGrid
DistGrid
F90
Data
Communications
Layout
Array
Comm
Route
C
Design Complete Limited Prototype Fuller Prototype
MachineModel
Utilities TimeMgr, Config, LogErr, I/O etc.
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Outline

• ESMF Design Goals
• ESMF Design Strategies
• Architecture and Features
• Implementation Strategy

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Implementation Strategy for ESMF Version 1.0

• Sufficient breadth to prototype how all major
  parts of the ESMF system will interact
• Well-developed superstructure (Components and
  States)
• Basic functions in most infrastructure classes

Superstructure
Infrastructure
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Implementation Strategy for ESMF Version 1.0
(cont.)

• Sufficient depth to develop simple ESMF
  applications
• Groundwork laid for high performance
  communication, uniform API across
  shared/distributed memory, load balancing
  capability
• Fully developed F90/C interoperability strategy

Superstructure
Infrastructure
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Implementation Strategy for ESMF Version 1.0
(cont.)

• Over the next year
• Development of grid and parallel regrid services
• Continued work on communication, decomposition,
  and other utilities
• Organization, standardization, fine-tuning
  interfaces
• Hardening and optimizing implementation
• Extending and polishing documentation and
  tutorial examples

Superstructure
Infrastructure
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Development Focus

• Near-term framework development focus is on
  creating sufficient infrastructure and
  superstructure to achieve the initial set of
  interoperability experiments.
• These are
• FMS B-grid atmosphere coupled to MITgcm ocean
• CAM atmosphere coupled to NCEP analysis
• NSIPP atmosphere coupled to DAO analysis

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The Team

• Fields and Grids
• Nancy Collins, Jon Wolfe, David Neckels
• Regrid
• Phil Jones
• Time Machine Model/Comms
• Earl Schwab
• Benchmarks
• Gerhard Theurich
• Web and Admin
• Robbie Stauffer

• I/O
• Nancy Collins, Atanas Trayanov
• Profiling and logging
• Shep Smithline, Erik Kluzek
• Attributes
• Leonid Zaslavsky, Nancy Collins
• System Tests and Demos
• Silverio Vasquez, Nancy Collins, Jon Wolfe
• Build
• Dennis Flanigan

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More information

• ESMF website http//www.esmf.ucar.edu
• On the website
• Information about the Community Meeting
• ESMF documents
• ESMF browsable source code repository
• On-line forms for community input and catalogued
  responses
• Milestone schedule, project archives and history,
  related projects
• Management plan, board and team contacts
• More