Known Problems - SPEChpc 2021

Introduction

This document describes known problems in SPEChpc 2021.

$Id$	Latest: www.spec.org/hpg/hpc2021/Docs/

Do you have a problem with SPEChpc?
Try these, in this order:

Update your copy with runcpu --update.
Check the latest version of Frequently Asked Questions.
Check the latest version of Known Problems.
Check the src.alt list. [What is a src.alt?]
Contact SPEC.

SPEChpc 2021 was tested on a variety of systems prior to release, including x86, Power, and ARM Linux systems. Nevertheless, as with any software product, problems may be found too late in the testing process to be fixed in the release, or may be discovered after release.

If you discover problems that are not listed here or in the FAQ, please report them to SPEC.

About the format of this document:

Problems may be added in the Open section from time to time. In each case, a workaround is given, if one is known.

When problems are fixed, they are moved to the Closed section.

Notice to maintainers: When updating this document, please do not ever re-use problem numbers.

Known Limitations

Benchmark	Description	Work around
LBM	LBM may fail to validate when using larger ranks counts, usually 2-4x that of the upper tested limit for each suite.	Use fewer ranks or use a suite intended for larger rank counts.
miniSweep	miniSweep may not validate with odd ranks counts (except 1 or 3).	Use even rank counts
SOMA	SOMA uses array reductions for OpenMP and OpenACC when the compiler claims support for the standard where array reductions were added. OpenMP=>201511, OpenACC=>201811. However some compilers do not actually include support for array reductions.	Add the define flag -DSPEC_NO_VAR_ARRAY_REDUCE to use an alternate source version that does not use array reductions. Note that since the alternate version is run serially on the host, it's expected to be less performant.

Benchmark

Description

Work around

LBM

LBM may fail to validate when using larger ranks counts, usually 2-4x that of the upper tested limit for each suite.

Use fewer ranks or use a suite intended for larger rank counts.

miniSweep

miniSweep may not validate with odd ranks counts (except 1 or 3).

Use even rank counts

SOMA

SOMA uses array reductions for OpenMP and OpenACC when the compiler claims support for the standard where array reductions were added. OpenMP=>201511, OpenACC=>201811. However some compilers do not actually include support for array reductions.

Add the define flag -DSPEC_NO_VAR_ARRAY_REDUCE to use an alternate source version that does not use array reductions. Note that since the alternate version is run serially on the host, it's expected to be less performant.

Open Problem Reports

Please see the latest on-line version of this document for information on open problems and suggested workarounds.

Benchmark	Description	Work around
miniSweep	miniSweep OpenMP may intermittently hang for certain compilers.	Use 'nodepend' src.alt package to remove the 'depend' clause from the source. 'depend' is likely causing a deadlock in some cases. Note that this has greatly decreased the occurrences of hangs, it may not completely fix the issue and additional modifications may be made in a future release of SPEChpc.

Benchmark

Description

Work around

miniSweep

miniSweep OpenMP may intermittently hang for certain compilers.

Use 'nodepend' src.alt package to remove the 'depend' clause from the source. 'depend' is likely causing a deadlock in some cases. Note that this has greatly decreased the occurrences of hangs, it may not completely fix the issue and additional modifications may be made in a future release of SPEChpc.

Closed Problem Reports

SPEChpc™ 2021 Known Problems

Introduction

Known Limitations

Open Problem Reports

Closed Problem Reports