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shmx(8)								      shmx(8)


  shmx - shared	memory exerciser


  /usr/field/shmx [-h] [-ofile]	[-ttime] [-msize] [-ssegment] [-v]


  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

      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
      <&lt;/sys/include/sys/param.h>&gt; file.)

  -sn Specifies	the number of memory segments.	The default and	maximum
      number is	3.


  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 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.


  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 executing it.


   1.  The following example tests the default number of memory	segments (3),
       each with the default segment size (SHMMAX/SHMSEG):
	    % /usr/field/shmx &&amp;

   2.  The following example runs two memory segments of size 100,000 bytes
       for 180 minutes:
	    % /usr/field/shmx -t180 -m100000 -s2 &&amp;


  Commands: cmx(8), diskx(8), fsx(8), memx(8), tapex(8)