hpc2021 Flag Description

Test sponsored by Telecommunications Technology Association

Flag descriptions for GCC, the GNU Compiler Collection

Note: The GNU Compiler Collection provides a wide array of compiler options, described in detail and readily available at https://gcc.gnu.org/onlinedocs/gcc/Option-Index.html#Option-Index and https://gcc.gnu.org/onlinedocs/gfortran/. This SPEC CPU flags file contains excerpts from and brief summaries of portions of that documentation.

SPEC's modifications are:
Copyright (C) 2006-2017 Standard Performance Evaluation Corporation

Permission is granted to copy, distribute and/or modify this document under the terms of the GNU Free Documentation License, Version 1.3 or any later version published by the Free Software Foundation; with the Invariant Sections being "Funding Free Software", the Front-Cover Texts being (a) (see below), and with the Back-Cover Texts being (b) (see below). A copy of the license is included in your SPEC CPU kit at $SPEC/Docs/licenses/FDL.v1.3 and on the web at http://www.spec.org/cpu2017/Docs/licenses/FDL.v1.3. A copy of "Funding Free Software" is on your SPEC CPU kit at $SPEC/Docs/licenses/FundingFreeSW and on the web at http://www.spec.org/cpu2017/Docs/licenses/FundingFreeSW.

(a) The FSF's Front-Cover Text is:

A GNU Manual

(b) The FSF's Back-Cover Text is:

You have freedom to copy and modify this GNU Manual, like GNU software. Copies published by the Free Software Foundation raise funds for GNU development.

Commands and Options Used to Submit Benchmark Runs

SPECrate runs might use one of these methods to bind processes to specific processors, depending on the config file.

• Linux systems: the numactl command is commonly used. Here is a brief guide to understanding the specific command which will be found in the config file:

  • syntax: numactl [--interleave=nodes] [--preferred=node] [--physcpubind=cpus] [--cpunodebind=nodes] [--membind=nodes] [--localalloc] command args ...
  • numactl runs processes with a specific NUMA scheduling or memory placement policy. The policy is set for a command and inherited by all of its children.
  • --localalloc instructs numactl to keep a process memory on the local node while -m specifies which node(s) to place a process memory.
  • --physcpubind specifies which core(s) to bind the process. In this case, copy 0 is bound to processor 0 etc.
  • For full details on using numactl, please refer to your Linux documentation, man numactl

• Solaris systems: The pbind command is commonly used, via
  submit=echo 'pbind -b...' > dobmk; sh dobmk
  The specific command may be found in the config file; here is a brief guide to understanding that command:

  • submit= causes the SPEC tools to use this line when submitting jobs.
  • echo ...> dobmk causes the generated commands to be written to a file, namely dobmk.

  • pbind -b causes this copy's processes to be bound to the CPU specified by the expression that follows it. See the config file used in the run for the exact syntax, which tends to be cumbersome because of the need to carefully quote parts of the expression. When all expressions are evaluated, the jobs are typically distributed evenly across the system, with each chip running the same number of jobs as all other chips, and each core running the same number of jobs as all other cores.

    The pbind expression may include various elements from the SPEC toolset and from standard Unix commands, such as:

    • $BIND: a reference to a value from the bind line, a line of the form "bind = n n n n", where each "n" is a processor number. See http://www.spec.org/cpu2017/Docs/config.html#bind for details on this feature.
    • $$: the current process id
    • $SPECCOPYNUM: the SPEC tools-assigned number for this copy of the benchmark.
    • psrinfo: find out what processors are available
    • grep on-line: search the psrinfo output for information regarding on-line cpus
    • expr: Calculate simple arithmetic expressions. For example, the effect of binding jobs to a (quote-resolved) expression such as:
      expr ( $SPECCOPYNUM / 4 ) * 8 + ($SPECCOPYNUM % 4 ) )
      would be to send the jobs to processors whose numbers are:
      0,1,2,3, 8,9,10,11, 16,17,18,19 ...
    • awk...print \$1: Pick out the line corresponding to this copy of the benchmark and use the CPU number mentioned at the start of this line.
  • sh dobmk actually runs the benchmark.

Commands and Options Used for Feedback-Directed Optimization

No special commands are needed for feedback-directed optimization, other than the compiler profile  flags.

Shell, Environment, and Other Software Settings

One or more of the following may have been used in the run. If so, it will be listed in the notes sections. Here is a brief guide to understanding them:

• LD_LIBRARY_PATH=<directories> (set via config file preENV)
  LD_LIBRARY_PATH controls the search order for libraries. Often, it can be defaulted. Sometimes, it is explicitly set (as documented in the notes in the submission), in order to ensure that the correct versions of libraries are picked up.

• OMP_STACKSIZE=N (set via config file preENV)
  Set the stack size for subordinate threads.

• ulimit -s N
  ulimit -s unlimited
  'ulimit' is a Unix commands, entered prior to the run. It sets the stack size for the main process, either to N kbytes or to no limit.

Flag description origin markings:

	Indicates that the flag description came from the user flags file.
	Indicates that the flag description came from the suite-wide flags file.
	Indicates that the flag description came from a per-benchmark flags file.

For questions about the meanings of these flags, please contact the tester.
For other inquiries, please contact info@spec.org
Copyright 2021-2023 Standard Performance Evaluation Corporation
Tested with SPEC hpc2021 v1.0.3.
Report generated on 2023-08-25 19:09:23 by SPEC hpc2021 flags formatter v1.0.3 .