Knights Landing Compilers And Tools

KNL Compilers and Tools

The Knight's Landing CPUs are true x86 CPUs, supporting also SSE, AVX, AVX2 instructions as well as AVX-512. Correspondingly code compiled for more or less any x86 system with say the GNU compiler collection will function. However, in order to generate code which takes full advantage of AVX-512 a recent compiler is needed, such as GCC-5.3 or the Intel Compiler Toolchain.

KNL System Overview

Using the Jefferson Lab Knights Landing Cluster

Using the Jefferson Lab Knights Landing Cluster

This page describes the Jefferson Lab Knights Landing Cluster

    Tape Scheduling

    Workflow - Swif

    What is Swif?

    Swif, the" scientific workflow indefatigable
    factotum", is a system that aims to simplify the use of Jefferson Lab's
    batch system.  As the name implies, it
    will work tirelessly on your behalf so that that you need not expend
    unnecessary effort to make good use of the compute farm.



    jcache - manage files and directories on the write-through cache area



    What changes are needed  to a jsub script when the job stages files to the write-through cache system?

    Write-through Cache

    The write-through cache system is a front end disk cache system to the tape library system. It enables a user with appropriate permission to deposit new files into the cache. The new files will be migrated into the tape library after a short period of time within which the files can be modified or deleted.

    Best Practices

    1. Try to submit multi-threaded jobs when possible. Using a multi-threaded job can save memory foot-print of the job and may increase the performance of the job.
    2. Let Auger manage the input and output files. Do not call jget/jput from the farm job. If jget/jput is called inside one's job, the time period which the job waits for the tape I/O to finish is counted toward the wall time of this job. Note: jget and jput inside Auger will be disabled in the near future.

    DAQ Support: Writing Raw Data to Tape

    All raw data from the experimental physics detectors goes through a number of steps to reach permanent storage on tape:
    1. The DAQ system assembles events and writes them into a raw data file on a local staging area.  This area is large enough to hold a minimum of 24 hours of high rate running.