Introduction to HPC resources for BCB 660 Nirav Merchant

 What is Parallel Computing ?  General overview of HPC systems  Overview of batch system (and why we need them)  Getting started with Ranger  Understanding the default user environment  Introduction to modules (and why we need them)  Submitting your first job (and monitoring it)  Moving your data in and out of HPC systems  Q/A Topic Coverage

 von Neumann Architecture  Named after the Hungarian mathematician John von Neumann who first authored the general requirements for an electronic computer in his 1945 papers.  Since then, virtually all computers have followed this basic design of:  Memory (RAM)  Control Unit (CPU)  Arithmetic Logic Unit (ALU)  Input/Output (Keyboard) What is computing ?

What does it look like (your computer) ? Image courtesy Univ. of Washington

Parallel computing: use of multiple processors or computers working together on a common task.  Each processor works on part of the problem  Processors can exchange information What is Parallel Computing? A good introduction to concepts for parallel programing is at:

 Traditional software is written to execute serially i.e. one task at a time running on one CPU  As the size of data (tasks) is increasing we need to utilize multiple CPU’s  Size of data also has implications on how much RAM and disk space is required for the task (we need more RAM or disk that fits on one computer) Why we need it

HPC systems: Not very different Image courtesy TACC at Univ of Texas

 HPC: High Performance Computing = Super Computing  Node: One self contained computer (many of which are connected together to form a “cluster”)  CPU = Socket = Processor = Cores  Interconnect: networking between Nodes (can be fiber optic, or regular ethernet like your computers) e.g. Infiniband or GigE Some Terminology (Jargon) of HPC

 Scalability: Ability to use additional resources to execute tasks faster  Embarrassingly Parallel: Data Parallel tasks where each task is independent and not much communication or coordination is required among tasks  Observed Speedup: “wall time” taken for serial task divided by wall time for parallel task More Terminology (Jargon) of HPC

 Shared memory  All CPU (processors) have access to shared RAM  Distributed memory  Each CPU (processor) has its own local memory, but can be connected to others nodes via fast interconnect Types of HPC

 Limits of single CPU computing  Performance  Available memory (Disk and RAM)  Parallel computing allows one to:  Execute Tasks that don’t fit on a single CPU  Complete tasks in a reasonable time  Again Please check: for basic intro to parallel computing concepts Again why do we need it ?

 Compute power  504 Teraflops  3,936 four socket nodes  62,976 cores, 2.0 GHz AMD Opteron  Memory  125Terabytes  2GB/core, 32 GB/node  Disk subsystem  1.7 PB Storage (Lustre Parallel File System)  1 PB in /work filesystem  Interconnect  8 Gb/s InfiniBand  Lonestar and others machines have similar (much larger specs) RANGER

 HOME  Store your source code and build your executables here  Use $HOME to reference your home directory in scripts  WORK  Store large files here  This file system is NOT backed up, use $ARCHIVE for important files!  Use $WORK to reference this directory in scripts  SCRATCH  Store large input or output files here – TEMPORARILY  This file system is NOT backed up, use $ARCHIVE for important files!  Use $SCRATCH to reference this directory in scripts  ARCHIVE  Massive, long-term storage and archive system  Check with staff before using this on your account Filesystem Access

Limits on your filesystem

How is it connected

 Please visit the TACC new user guide for RANGER  You will pick up many hints that will make your life MUCH easier for running tasks on TACC resources  guides/ranger-user-guide guides/ranger-user-guide  (same as above) MUST READ THIS

 With multiple users we need a way to organize tasks  We need a way to assign suitable resources to the tasks (track, prioritize)  With multiple software we need a way to deal with conflicts in version and dependency per tasks  Batch scheduler user on all TACC systems is SGE (Sun Grid Engine) now owned by Oracle. Batch, Module system

Batch submission

RANGER: Queue Options

Common SGE commands

Lets get working ssh

Module Commands

Compbio stack/modules

 Modules are for global use, hard to get cutting edge code as modules (limited staff time)  You can always compile and use your own versions without waiting for a module to be built  When possible, build your applications from source rather than running pre-compiled binaries  If you choose to use “make Install”, you will need to modify the “configure” script to change where it is installed ./configure --prefix=$HOME/bin  For best performance, use the the intel compilers  For best compatibility, use the gcc compilers  More in “bleeding edge s/w” slide But my favorite app is …

 Number of cores and nodes to use is set with: #$ -pe Nway 16*M  N represents the number of cores to utilize per node Ranger: 1≤N≤16 Lonestar:1≤N≤12  M is the number of nodes to utilize  The TOTAL number of cores used is thus: N*M Preparing for tasks

Preparing a job submission

Some more SGE options

 /wiki /wiki  (same url as above just short)  Lets look at the tutorial section towards the end of the page Working with bleeding edge s/w

More from that page

 SCP will work well for most smaller files  Specialized options (bbcp and gridftp need special end point installation)  As you get larger files (10Gb+) it gets time consuming to move it around  Easier to move your data into iPlant data store from your desktop/server (parallel transfers)  Pull that data where you need (and push more into it)  Command line and GUI options (including dropbox for science) Getting data in and out

 Details at:   Connecting from RANGER  module load irods  iinit  Answer the prompts using info from above link  You are now connected (without future need of passwords to iPlant data store) iPlant data store

From RANGER After loading irods module i.e module load irods

 You have many tasks that you want to run and they are naturally parallel (“embarrassingly parallel” )  Parametric Job Launcher: a simple utility for submitting multiple serial applications simultaneously.  % module load launcher  2 key components:  paramlist execution command  launcher.sge job submission script Parametric Launcher

 Check  /wiki/TACC_NGS_Course_Practical_1 /wiki/TACC_NGS_Course_Practical_1   Look at the shrimp_launcher.sge for ideas Parametric Launcher

 TACC Staff for slides  Matt Vaughn  Michael Gonzalez  And many more  URL  guides/ guides/ Gratitude