Sun Microsystems SPEC CPU Flags: Sun-OpenSolaris-Studio-x86_64

Compilers: Sun Studio 12 Update 1

Operating systems: OpenSolaris 2008.11

Last updated: 21-Apr-2009 jlh

The text for many of the descriptions below was taken from the Sun Studio Compiler Documentation, which is copyright © 2007-2009 Sun Microsystems, Inc. The original documentation can be found at

This document has both optimization flags (in the immediately following section) and a description of Platform Settings


Selecting one of the following will take you directly to that section:

Optimization Flags

Compiler Flags

Other Flags

Forbidden Flags

System and Other Tuning Information

Platform settings

One or more of the following settings may have been applied to the testbed. If so, the "Platform Notes" section of the report will say so; and you can read below to find out more about what these settings mean.

Boot time, BIOS settings

Intel VT-d: Disabled
VT-d, if enabled, supports remapping of I/O DMA transfers for virtualization.

/etc/system settings

When the file system flush daemon fsflush runs, it writes to disk all modified file buffers that are more than n seconds old.

0 = the OS may allocate remote pages if the size requested is readily available in a remote locality group (default)
1 = Set lgroup page allocation to strongly prefer local pages.

Controls the number of seconds between runs of the file system flush daemon, fsflush.

Controls the amount of memory used by ZFS for caching of file system buffers.

Environment/shell variables

Enables (TRUE) or disables (FALSE) dynamic adjustment of the number of threads available for execution of parallel regions. The default is TRUE.

Enables or disables nested parallelism. Value is either TRUE or FALSE. The default is FALSE.

If programs have been compiled with -xautopar, this environment variable can be set to the number of processors that programs should use.

If programs have been compiled with -xautopar, this environment variable can be set to the number of processors that programs should use.

Set the size of the stack (temporary storage area) for each slave thread of a multithreaded program.

This environment variable can be used to bind the LWPs (lightweight processes) managed by the microtasking library, libmtsk, to processors. Performance can be enhanced with processor binding, but performance degradation will occur if multiple LWPs are bound to the same processor.
The value for SUNW_MP_PROCBIND can be:

Integers in the above denote the "logical" processor IDs to which the LWPs are to be bound. Logical processor IDs are consecutive integers that start with 0, and may or may not be identical to the actual processsor IDs. If n processors are available online, then their logical processor IDs are 0, 1, ..., n-1.
By default, LWPs are not bound to processors. It is left up to the operating system, Solaris, to schedule LWPs onto processors.
If the value "TRUE" is used, the operating system will bind processes to processors, starting with processor 0.

Controls the end-of-task status of each helper thread executing the parallel part of a program. You can set the value to spin, sleep ns, or sleep nms. The default is SPIN -- the thread spins (or busy-waits) after completing a parallel task until a new parallel task arrives.

ulimit -s <n>
Sets the stack size to n kbytes, or "unlimited" to allow the stack size to grow without limit.

The Submit Command

submit=echo 'pbind -b...' > dobmk; sh dobmk
When running multiple copies of benchmarks, the SPEC config file feature submit is sometimes used to cause individual jobs to be bound to specific processors. If so, the specific command may be found in the config file; here is a brief guide to understanding that command: