ekea : E3SM Kernel Extractor and Analyser

ekea automates the process of kernel extraction from a large Fortran applicatin. Especially, it is customized for E3SM so that, in many kernel extraction cases from E3SM, user only needs to specify a E3SM case directory and a code region for kernel extraction.

To use ekea, ekea needs be installed on the system where E3SM case directory and E3SM source files exist.

Installation

The easiest way to install ekea is to use the pip python package manager.

>>> pip install ekea

You can install ekea from github code repository if you want to try the latest version.

>>> git clone https://github.com/grnydawn/ekea.git
>>> cd ekea
>>> python setup.py install

Once installed, you can test the installation by running the following command.

>>> ekea --version
ekea 1.1.2

Requirements

• Linux OS
• Python 3.5+
• Make building tool(make)
• C Preprocessor(cpp)
• System Call Tracer(strace)

E3SM Kernel Extraction

Once ekea is installed correctly and a E3SM case is created successfully, you can extract a kernel as explained below.

The syntax of ekea command for simple usage is following:

>>> ekea <ocn|eam> $CASEDIR $CALLSITEFILE

, where $CASEDIR is a directory path to E3SM case directory and $CALLSITEFILE is a file path to a E3SM source file containing ekea kernel region directives(explained below).

Next to "ekea" command, user chooses one of two subcommands(ocn or eam) for MPAS Ocean Model and E3SM Atmospheric Model each.

Kernel region directives

As shown below, a pair of "begin_callsite" and "end_callsite" directives defines an ekea kernel region in source code. The kernel region is where to be extracted as a kernel. Following example shows a ekea kernel region that encompasses a DO loop.

! file path : /my/E3SM/components/eam/src/file.F90

!$kgen begin_callsite vecadd
DO i=1
    C(i) = A(i) + B(i)
END DO
!$kgen  end_callsite

Kernel extraction command

Assuming that the E3SM case directory is "/e3smcases/mycase" and the above ekea kernel region directives are specified in "/my/E3SM/components/eam/src/file.F90" under EAM source directory, the full ekea command is below:

>>> ekea eam /e3smcases/mycase /my/E3SM/components/eam/src/file.F90

ekea documentation: https://ekea.readthedocs.io