shmx.8

<B>Digital的Unix操作系统VAX 4.2源码</B>

.\" SCCSID: @(#)shmx.8	8.1	9/11/90
.TH shmx 8 
.SH Name
shmx \- shared memory exerciser
.SH Syntax
.B /usr/field/shmx
[
.B \-h
] [
.BI \-o file
.B ] [
.BI \-t i
.B ] [
.BI \-m j
.B ] [
.BI \-s k
.B ] [
.BI \-v
.B ]
.SH Description
.NXR "shmx exerciser"
.NXR "shared memory" "exercising"
The 
.PN shmx 
memory exerciser spawns a background
process
.PN shmxb
and these two processes exercise the shared memory
segments. They each take turns writing and reading
the other's data in the segments.
.PP
You can specify the number of memory segments to test 
and the size of the segment to be tested by  
.PN shmx
and
.PN shmxb
processes. The 
.PN shmx
exerciser
runs until the process
receives a
.CT C
or a kill \-15 \fIpid\fR.
.PP
A logfile is made in 
.PN /usr/field
for you to examine and then remove. If there are errors
in the logfile, check the 
.PN /usr/adm/syserr/syserr.<hostname> 
file, where the driver and kernel error
messages are saved.
The 
.PN shmx
exerciser is automatically invoked when the 
.PN memx
exerciser is started.  You can also run 
.PN shmx
by itself.
.SH Options
.IP \fB\-h\fR 10
Print the help message for the
.PN shmx
command.
.IP \fB\-v\fR
Use the 
.MS fork 2
system call instead of 
.MS vfork 2
to spawn
.PN shmxb .
.IP \fB\-o\fIfile\fR
Save diagnostic output in \fIfile\fR.
.IP \fB\-t\fIi\fR
Run time in minutes (\|\fIi\fR\|).  The default is to run until
the process receives a
.CT C 
or a kill \-15 \fIpid\fR.
.IP \fB\-m\fIj\fR
The memory segment size in bytes (\|\fIj\fR\|) to be tested by the
processes.  Must be greater than 0.  The default is
SMMAX/6.  (SMMAX is a system parameter set in the file
.PN sys/conf/param.c .) 
.IP \fB\-s\fIk\fR
The number of memory segments (\|\fIk\fR\|).  The default is 6.
The maximum is also 6.
.SH Examples
The following example tests six memory segments (default),
each with a segment size of SMMAX/6, until a
.CT C
or kill \-15\fI pid\fR is received:
.EX
% /usr/field/shmx 
.EE
The following example runs three memory segments of size 100,000
bytes for 180 minutes in the background:
.EX
% /usr/field/shmx \-t180 \-m100000 \-s3 &
.EE
.SH Restrictions 
If there is a 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 
.MS fsx 8 ,
the target file system must be writable by root.  Also the 
directory, in which any of 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.  
.SH See Also
.I Guide to System Exercisers