shmx - shared memory exerciser
/usr/field/shmx [-h] [-ofile] [-ttime] [-msize] [-ssegment]
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. Specifies
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 maximum number
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 exerciser runs until the process is
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.
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 restrictions may be overcome
by copying the exerciser to another directory and then
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 &
Commands: cmx(8), diskx(8), fsx(8), memx(8), tapex(8)
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