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shmx(8) System Manager's Manual shmx(8) NAME shmx - shared memory exerciser SYNOPSIS /usr/field/shmx [ -h ] [ -ofile ] [ -ttime ] [ -msize ] [ -ssegment ] [ -v ] 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 sys- log 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. FLAGS You can use the following options: -h Prints the help message for the shmx command. -v Uses the fork(2) system call instead of the vfork(2) call to spawn shmxb. -ofile Saves diagnostic output in file. -ttime Specifies the run time in minutes. The default is to run un- til the process is killed. -msize Specifies the memory segment size in bytes to be tested by the processes. Must be greater than 0. The default is SHM- MAX/SHMSEG. (SHMMAX and SHMSEG are system parameters set in the /sys/include/sys/param.h file.) -sn Specifies the number of memory segments. The default and maximum number is 3. 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 ex- ecuted 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 & RELATED INFORMATION cmx(8), fsx(8), memx(8), tapex(8), diskx(8) delim off shmx(8)