The Distributed-Parallel Storage System (DPSS)
TerraVision Simulator (tv_sim)
Lawrence Berkeley National Laboratory, Data Intensive
Distributed Computing Project
This page contains instructions for using the LBL TerraVision
Simulator with the DPSS.
What's New (4/18/97)
- tv_sim makes only "now"-priority requests by default.
- Marcia Perry of
IDCG added Tcl/Tk hooks to tv_sim. A
screen shot is available.
We'll be refining the interface as time goes by.
Index
tv_sim can be used for testing tile sets created for TerraVision.
In particular, tv_sim, in conjunction with the DPSS, can be used
to verify that the DPSS and the underlying network are
functioning correctly.
tv_sim generates lists of requests for tiles from a specified
tile set or sets, and receives the resulting tile information
from the DPSS as quickly as possible. Users can set the rate
at which requests are made, the duration of the session, and
the source of the requests. tv_sim can also log the timestamp
and/or some statistical information about the received tiles.
Note that tv_sim does not display the tiles; to see the data,
use ibrowse.
If your environment is properly set up (see Environmental variables),
tv_sim can be invoked by simply specifying a set ID:
tv_sim -s SET_ID
The program will run until interrupted (i.e., until a SIGINT is
sent to one of the running processes, usually via a Control-C
from the keyboard).
tv_sim's default behavior,
describes what the program does if invoked without other
command-line options. The default behavior can be altered to
suit your needs; see Modifying tv_sim's default
behavior.
To use tv_sim, first make sure your DPSSHOST
environment variables is correct. DPSSHOST should be the name of
the host running the DPSS master process you plan to use. In
general, this should be the DPSS closest to you.
You may want to add lines similar to this to your .cshrc file:
setenv DPSSHOST godiva-atm.uswest.magic.net
To verify the DPSS is both up and running correctly,
run "iss_status". The output should indicate
that both programs are UP.
You can run dsm_list to get a list of currently
available data sets. Note that although tv_sim can now handle more
than just TerraVision pyramid tile sets, it cannot handle all types
of data. However, tv_sim will exit with an error message if it
encounters a data type it does not understand.
- Uses the DPSS specified in the DPSSHOST environmental
variable
- Sends 5 request lists a second
- Randomly generates 10 requests per request list
- Makes all requests priority "now". Note:
this is different from its former default behavior in versions
prior to 2.7.
- Runs until interrupted (SIGINT)
- Prints the approximate rate at which it is receiving data
in Mb/s over a 40-block interval (non-cumulative
"snapshot" average)
- Creates no logs of its activities
Command line flags control most aspects of tv_sim's performance.
As yet, there is no way to change its behavior while it is
running.
-
- -i DPSS_HOST forces tv_sim to use DPSS_HOST as
the DPSS; this overrides the DPSSHOST environmental
variable.
-
When more than one data set is specified on the command line, the
data set specified with -S is the "preferred" data set; the DPSS is
instructed to prepare the others, but tv_sim does not make requests
from them. If no preferred data set is specified, tv_sim
distributes its requests among all specified data sets. A
single data set may be specified using either -s or -S.
Note: unless tv_sim is in playback mode, the user
must specify a data set to use.
-
- -f NUMBER changes the request list rate to NUMBER
lists per second
- -F NUMBER changes the request list rate to NUMBER
lists per minute
- -r NUMBER changes the number of requests per
request list to be NUMBER
For any of the request rate options, if NUMBER is -1, tv_sim
will randomly vary the values (within reasonable bounds).
-
The DPSS recognizes three priorities of requests.
"Now" requests are the norm for most applications.
"Later" and "never" requests are primarily
for use by applications such as TerraVision
which use a predictive algorithm. For more information, see this
page concerning the structure of request lists.
- -l NUMBER forces each request list to contain
NUMBER requests of priority "later".
- -n NUMBER forces each request list to contain NUMBER
requests of priority "never".
For either -l or -n, if NUMBER is -1, tv_sim
will randomly vary the values (within reasonable bounds).
In order to test network performance, we have found it useful
to invoke tv_sim with -l 0 -n 0 to force all requests
to be priority "now".
- -j forces tv_sim to request each block or frame
of a data set once and only once in a unique and reproducible
order.
-j is chiefly useful as a diagnostic aid to the DPSS
development group and is probably not of great interest to anyone
else.
-
Instead of generating its own requests, tv_sim can get its
requests from a playback file. A playback file can be
generated by the DPSS by starting the DPSS master with the -c
option and running TerraVision
or tv_sim itself.
- -p [PLAYBACK_FILE] forces tv_sim to send the
requests in PLAYBACK_FILE, in sequence, once.
- -P [PLAYBACK_FILE] forces tv_sim to send the
requests in PLAYBACK_FILE, in sequence, forever, by repeating
PLAYBACK_FILE's request sequence indefinitely in a loop.
If PLAYBACK_FILE is not specified, tv_sim looks for a file
called tv_playback.
For once-only playback, tv_sim will quit after cycling through
the playback file once. Repeated playback must be interrupted
using SIGINT, as normal.
The playback file preserves both the composition of request
lists and their timing (i.e., the relative delay between one
list and the next). However, by default, tv_sim ignores the
original session's request rate and uses its default request
rate. To recreate the original session's timing, you must
override the defaults by specifying -f -1 and -r
-1.
By default, tv_sim uses the data set ID stored in the playback file.
-S substitutes the selected set ID instead.
-
You can explicitly limit how long tv_sim runs by using the
"expire" options:
- -x NUMBER causes tv_sim to quit after NUMBER
seconds.
- -X NUMBER causes tv_sim to quit after NUMBER
minutes.
Expiration times do not include the time needed to contact the
DSM and DPSS or to initialize tv_sim itself.
If either the -X or -x option is used with playback, tv_sim will
run until either the playback file is finished (if -p) or the
specified amount of time has passed, whichever comes first.
-
Use either the Netlogger logging
utilities or the tv_sim logging format.
- -L u saves NetLogger information to a logfile in
the current directory.
- -L s saves NetLogger information to the system
log.
- -L f saves tv_sim performance statistics for each
received tile and a list of requested tiles to a logfile in
the current directory.
- -L c saves minimal tv_sim information about tiles
sent and received to a logfile in the current directory.
Except for the -L f and -L c options, any
logging option can be used with any other.
-
- -d [LEVEL] prints debug messages at debugging
level LEVEL; if LEVEL is not given, the default is 1
- -v makes tv_sim more verbose
- -h prints tv_sim's short usage message
- -H prints tv_sim's long usage message, with
explanations of each option and information about how to
invoke help messages for specific options
tv_sim prints its version number with either the -h or -H option. The
current version is 2.7. The only current difference between 2.6 and 2.7
is a minor bug fix for OSF/1 and the suppression of "later"-
and "never"-priority requests in 2.7.
You can email any problems you find with tv_sim to Gary Hoo
COPYRIGHT NOTICE:
Distributed Parallel Storage System and DPSS/ISS are Copyright © 1994 by Lawrence Berkeley
Laboratory
This page is the resonsiblity of
Brian L. Tierney.
(BLTierney@lbl.gov).
Support Credits are here.
This document and its uses are subject to LBL's disclaimers and legal
notices.
Credits: The research and development of the Distributed Systems Department i
s funded by the U.S. Dept. of Energy, Office of Science, Office of Advanced Scie
ntific Computing Research, Mathematical, Information, and Computational Sciences
Division
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This page last modified: Thursday, 14-Oct-1999 16:27:27 PDT
