pvm(1pvm) [debian man page]
PVM(1PVM) PVM Version 3.4 PVM(1PVM) NAME
pvm - PVM version 3 console SYNOPSIS
pvm [ -options ] [ hostfile ] DESCRIPTION
Pvm is a stand alone PVM task which allows the user to interactively query and modify the virtual machine. The console can be started and stopped multiple times on any of the hosts in the virtual machine without affecting PVM or any applications that may be running. When started pvm determines if PVM is already running and if not automatically executes pvmd3 on this host, passing pvmd3 the command line options and host file. Thus PVM need not be running to start the console. Once started the console prints the prompt: pvm> The following console commands are available: add hostname(s) - Add hosts to virtual machine alias - Define/list command aliases conf - List virtual machine configuration delete hostname(s) - Delete hosts from virtual machine echo - Echo arguments export - Add environment variables to spawn export list halt - Stop pvmds help [command] - Print helpful information about a command id - Print console task id jobs - List running jobs kill task-tid - Terminate tasks mstat host-tid - Show status of hosts ps -a - List all PVM tasks pstat task-tid - Show status of tasks quit - Exit console reset - Kill all tasks setenv - Display/set environment variables sig signum task - Send signal to task spawn [opt] a.out - Spawn task opts are: -(count) number of tasks, default is 1 -(host) spawn on host, default is any -(ARCH) spawn on hosts of ARCH -? enable debugging -> redirect task output to console -> file redirect task output to file ->>file redirect task output append to file trace - Set/display trace event mask unexport - Remove environment variables from spawn export list unalias - Undefine command alias version - Show libpvm version pvm reads $HOME/.pvmrc before reading commands from the tty, so it can be used to customize the console environment, for example: alias ? help alias j jobs setenv PVM_EXPORT DISPLAY # print my id echo new pvm shell id EXAMPLES
pvm Starts up pvmd3 on the local host or connects to running pvmd3. pvm hostfile Starts up console and pvmd3, which in turn reads the host file and adds the listed computers to the virtual machine. SEE ALSO
pvm_intro(1PVM), pvmd3(1PVM) 30 August, 1993 PVM(1PVM)
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PVM_SHMD(1PVM) PVM Version 3.4 PVM_SHMD(1PVM) NAME
pvm_shmd - PVM shared memory(2) daemon SYNOPSIS
pvm_shmd [ -options ] [ hostfile ] DESCRIPTION
Pvm_shmd is a daemon process which maintains and handles the usage of shared memory resources (memory segments, semaphores, message queues) on a particular PVM host. One pvm_shmd must run on each host in a virtual machine that wants to use the shmd shared memory message passing layer. The shmd message passing layer allows local processes to a host to use shared memory for message passing on that host ONLY. See the shmd directory README for further notes and restrictions. The daemon can be started manually as with any other PVM task. Only one pvm_shmd can be active per host. If the pvm_shmd detects another pvm_shmd it will shutdown. The pvm_shmd can be killed from the PVM console by using the reset command. Local and remote pvm_shmds can also be started from the PVM console program pvm. The name of the daemon executable is pvm_shmd. Shared Resource Usage The pvm_shmd will attempt to create upto MAXSEG shared memory segments of upto MAXPAGES memory pages in size. The size of each memory page is architecture dependent(see getpagesize(3C)). The segments are then numbered 0..N-1 where N is the number of segments created. The first segement(0) has the shared memory control structure placed in its head. This structure allows alien processes to located the other shared memory segments and any required controlling information. The message passing layer, allocates memory from these segments asynchronously without any interaction with the pvm_shmd using semaphores to protect data during updates to any associated structures. For each segment there is an associated page map of which processes have cur- rently locked a page. Each page map for a segment has a separate semaphore protecting it. The semaphores are accessed with the SEM_UNDO flag set so that if a process holding a semaphore should die, the OS (should) reset the semaphore automatically, thus allowing any wait- ing/blocked processes to continue. The pvm_shmd only maintains the segments and their allocation page map(s). Thus if a process allocated pages in a segment and then exits, it is the pvm_shmd that detects this and then frees the allocated pages. The pvm_shmd can have its status checked at any time by using the pvm_shmd_stat process to kick it into reporting onto either stdio or the pvm log file (pvml.uid) its internal state. The shared memory and all associated processes can be cleared by sending the pvm_shmd a HUP signal. Sending the pvm_shmd a TERM signal will just cause it to clear any shared resources and then exit. The pvm_shmd cannot catch the KILL signal. If the pvm_shmd is killed without clearing all of its shared resources these can be cleared by calling ipcfree which resides in the pvm3/lib directory. Message Passing using SHMD The pvm_shmd handles resources that are used by special versions of pvm_psend() and pvm_precv() stored in the libpvmshmd.a library. Thus to use these facilities, applications have to link to this library instead of the usual libpvm3.a library. OPTIONS
The following options may be specified on the command line when starting the pvm_shmd: -debug=level Sets the pvm_shmd debug level. Used to debug the pvm_shmd or libpvmshmd (not intended to be used to debug application programs). -maxsegs=maxsegs Sets the maximum number of segments that the pvm_shmd can create. This is used to over-ride the compiled in value from shmd.h. Note that the value cannot be above the MAXSEGS in the shmd.h file. -maxpages=maxpages Sets the maximum segment size to maxpages pages of memory. This value cannot be above the compiled value MAXPAGES in shmd.h or the actual OS defined limit. NOTES
Remember that pvm_shmd allocated memory from the VM available on the machine. Allocating more segements improves performance as there is less sharing of segments (semaphores for their page maps). Although you must remember to leave some memory available for normal program and OS system usage, as the pvm_shmd allocated memory is *ONLY* used for message passing. FILES
$PVM_ROOT/lib/$PVM_ARCH/pvm_shmd PVM shared memory daemon executable $PVM_ROOT/shmd/shmd.h Shared Memory hard limits header file /tmp/pvml.uid Pvmd runtime error log SEE ALSO
pvm(1PVM), pvmd(1PVM), getpagesize(3C), ipcs(1), msgctl(2), semctl(2), shmctl(2), signal(5) G.E.Fagg 11 March, 1999 PVM_SHMD(1PVM)