NERSC Software Roadmap David Skinner, NERSC Division, Berkeley Lab

NATIONAL ENERGY RESEARCH SCIENTIFIC COMPUTING CENTER

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NERSC Software Roadmap

David Skinner, NERSC Division, Berkeley Lab


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Overview

• AIX 5L – 32/64 bit issues

• Compiler Upgrades

• Applications and Libraries


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AIX 5L @ seaborg : End of July • Most changes are in the kernel or systems software

• User environment is very similar to AIX 4.3

• NERSC will continue to use a 32 bit kernel and the default mode for compiled objects will also be 32 bit, until the end of the year.

• 64 bit MPI, PMAPI, hpmtoolkit will no longer be beta

• Key point: 32 and 64 bit objects can not be linked (ld nm and ar use the “-X64” flag to specify the bit mode)

• 64 bit objects compiled under AIX 4.3 will not work under AIX 5L


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AIX 5L (continued)

• ksh93 • /usr/sbin/bindprocessor1. To see which processors are available:

bindprocessor -q e.g. “The available processors are: 0 1 2 3”2. To bind the threads in process 19254 to processor 1:

bindprocessor 19254 1

• Begin/EndCriticalSection() calls• See IBM Redbook “AIX 5L Differences Guide” for more

information


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Compiler Upgrades: Applied After AIX upgrade

IBM XL Fortran 7.1.1

Fortran 90/95

OMP 1.0

8.1

~Fortran 200x

OMP 2.0

IBM XL C 5.0.2

ISO C 89

OMP 1.0

6.0

ISO C 99

OMP 2.0

IBM XL C++ 5.0.2

ANSI 98 C++

No OMP

6.0

ANSI 98 C++

OMP 1.0


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New xlf features

• Int2

• TYPE I/O intrinsic

• SIZEOF intrinsic (ala the C sizeof(TYPE) call)

• Selected Fortran 200x features– IEEE Modules

– Allocatable components (define allocatable sotrage in strcuts)

– Intent for f90 pointers

• VAX structure and Union


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New C/C++ Features

• OMP 1.0 for C++

• complex type

• restrict keyword

• variable length arrays

• inline function specifier

• hex floating constants

• partial initialization of structs/aggregate using names

• function like macros with VARARGS

• Misc. improvements with templates

• gcc binary compatibility, name mangling (C only)

• Dropped: LPEX editor, incremental compiler, IBM IOC library


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New Options

• -qsmallstack

for large numbers of threads, less stack overhead

• -qessl

Automatically use essl for f90 intrisics like matmul

• -qsmp=noopt

To debug omp codes. This option skips optimization that may interfere with debugging. Currently –qsmp=omp implies optimization.


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New OpenMP API

• workshare

• copyprivate

• num_threads

• nestable locks

• omp_get_wtime, omp_get_wtick

• arrays in reduction clauses


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New Compiler Bugs (none planned)

• The compiler bug resolution process ay NERSC

bug report NERSC confirms reduce to supported SWmake testcase send to IBM wait or for efix install/test

• Efixes are often installed live, please report regressions quickly, as they can sometimes be undone.

• Multiple Compiler Version Support:

will allow user to choose the feature set (and bug set) most appropriate to their codes.


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Going Away

• KCC - Will be Intel only in future versions

• xldb - Unsupported later this Summer


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New gcc/g++

• NERSC staff will try to keep these up to date

• Currently some incompatibilities between

libg++ and the AIX linker regarding weak symbols

• gcc/g77 can use -mpe to create POE executables– This flag provides a “mpgcc” etc.


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AIX Linux Affinity• IBM initiative to provide AIX with user environment and features from Linux

• E.g., zlib, openssh, libungif, libtiff, libpng, rpm, perl suite etc packaged for AIX at http://www.ibm.com/servers/aix/products/aixos/linux/

• IBM compilers will support the following compiler extensionsfrom gcc/g++ to enhance Linux/AIX interoperability.

Language Constructs local labelstypeof

function attributes* support for noreturn, const, weak, and pure* accept and ignore the rest of many platform specific attributes

Directives#cpu, #assert, #unassert,#machine, #system, #warning#pragma unroll#pragma pack#pragma weak


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Future Compiler Directions

Foccus will be on improving:

-qpdf profile directed inlining , instrumentation feedback opt

-qipa being continued worked on

-qhot and -qipa will do loop level optimization globally


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Applications and Libraries on seaborg

ChemistryQchemNAMD GaussianNWChemAmber

LibrariesESSLPESSLBLASScaLAPACKLAPACKFFTWPETSCMASSAztecPMAPIPAPINAG(Par)MetisHDFnetCDF

ToolsTotalviewZerofaultVampirVASTKAP

UtilitiesEmacsVimGhostscriptGNU.toolsMySQL

VisualizationdxAVSIDLVMDxv


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Requesting Software

• Use “module avail” to see if it’s already available

• HPC libraries of general use with friendly licenses are preferred

• Online request forms:

http://hpcf.nersc.gov/forms/nuser_only/sw_orderform.html


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NERSC Software Roadmap David Skinner, NERSC Division, Berkeley Lab

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