shmx(8)shmx(8)NAMEshmx - shared memory exerciser
SYNOPSIS
/usr/field/shmx [-h] [-ofile] [-ttime] [-msize] [-ssegment] [-v]
OPTIONS
You can use the following options: Prints the help message for the shmx
command. Uses the fork(2) system call instead of the vfork(2) call to
spawn shmxb. Saves diagnostic output in file. Specifies the run time
in minutes. The default is to run until the process is killed. Speci‐
fies the memory segment size in bytes to be tested by the processes.
Must be greater than 0. The default is SHMMAX/SHMSEG. (SHMMAX and
SHMSEG are system parameters set in the </sys/include/sys/param.h>
file.) Specifies the number of memory segments. The default and maxi‐
mum number is 3.
DESCRIPTION
The shmx memory exerciser spawns the background process shmxb, and
these two processes exercise the shared memory segments. They alternate
writing and reading the other process' data in the segments.
You can specify the number of memory segments to test and the size of
the segment to be tested by shmx and shmxb processes. The shmx exer‐
ciser runs until the process is killed.
A log file for you to examine and then remove is created in the current
working directory. If there are errors in the logfile, check the syslog
files where the driver and kernel error messages are saved. The shmx
exerciser is automatically invoked when the memx exerciser is started.
You can also invoke shmx manually.
RESTRICTIONS
If you need to run a system exerciser over an NFS link or on a diskless
system, there are some restrictions. For exercisers that need to write
into a file system, such as fsx(8), the target file system must be
writable by root. Also the directory from which the exercisers are
executed must be writable by root because temporary files are written
into the current directory. These latter restrictions are sometimes
difficult to overcome because often NFS file systems are mounted in a
way that prevents root from writing into them. Some of the restric‐
tions may be overcome by copying the exerciser to another directory and
then executing it.
EXAMPLES
The following example tests the default number of memory segments (3),
each with the default segment size (SHMMAX/SHMSEG): % /usr/field/shmx &
The following example runs two memory segments of size 100,000 bytes
for 180 minutes: % /usr/field/shmx -t180 -m100000 -s2 &
SEE ALSO
Commands: cmx(8), diskx(8), fsx(8), memx(8), tapex(8)shmx(8)
