chrisv@CMC.COM (Chris VandenBerg) (03/06/91)
Good morning all, I tried posting the following question to the X windows interest group but received NO responses. So I'm going to give it a go here on TCP, since most of you ARE concerned with bandwidth usage for applications, etc. QUESTION - Does anyone have a feel for rough bandwidth usage for some of the "typical" (if there is such a thing) X client applications? Has anyone run any benchmarks which included X sessions across the net? It can't be too difficult to fill up an Ethernet VERY quickly running clients to a few servers doing CAD or something. If you have some applications that can eat up an Ethernet let me know, we're actively looking for good app's to highlight the need for FDDI at Interop this year. Many thanks, Chris VandenBerg CMC A Rockwell Co. chrisv@cmc.com 805-562-3127
tmallory@BBN.COM (03/06/91)
Chris, While not very sexy, performing file system backups over the net is a necessary and bandwidth hungry application. Our corporate communications folks are concerned that an FDDI backbone might be not be enough to get all remote systems backed up to come central site in the not too far distant future. You might consider loading up 50% of the ring with this sort of traffic, and then run some of the apps that other people will be suggesting. Tracy
ty@STYX.DESKTALK.COM (Tyson M. Kostan) (03/07/91)
Tracy & Chris, I would never recommend doing all backups to a central machine on such a wide scale. Maybe the network could be physically broken (i.e routers) into work- groups, with a small workgroup server on each workgroup. This will definately be more economical overall, considering the requirements on a central server. ...Ty
phil@shl.com (Phil Trubey) (03/09/91)
In article <9103051621.AA05970@cmc.com> chrisv@CMC.COM (Chris VandenBerg) writes: >QUESTION - Does anyone have a feel for rough bandwidth usage for some of the >"typical" (if there is such a thing) X client applications? Has anyone run any >benchmarks which included X sessions across the net? I did a quick and dirty 'bandwidth benchmark' a few weeks ago to determine how much bandwidth a typical X session takes up. Following is a synopsis of what I did. Please keep in mind that I was using an NCD X Terminal which was *not* blindingly fast. A faster X terminal could easily double the bandwidth requirements (I would think). I'm going to be performing these tests again sometime in the next few weeks with a fast SparcStation acting as an X terminal to see what changes. For those that don't want to wade through this, I found that I used about 68 kbps average bandwidth for screen redraws. ---- A series of tests were performed and the results analyzed. The test environment consisted of a Sun 4/260 Unix computer on an ethernet along with an NCD X terminal. A LAN protocol analyzer and a network monitoring package was also attached to the network. The protocol analyzer was set up to record all packets going to or coming from the X terminal. The Ingres 4GL Windows environment was run on the Sun computer with all output being directed to the X terminal. A sample Ingres Windows/4GL database application was run under the Motif window manager during the tests. Four sampled tests were conducted: - Initiation of the application program. This involved invoking the application through a pull down menu. The application drew a full screen form consisting of about 10 buttons, 3 scroll bars, 15 boxes, and 20 text fields. This is a fairly representative X window database form. The test stopped after the form had been completely drawn. - Data entry. Using the above form, the test caught about 1.5 minutes of fairly rapid data entry activity which included entering text and numbers, checking boxes, and pressing buttons. Part of the test included pressing a button that displayed a 1/2 screen size pop up window with a histogram displayed. - Switching between two windows. This test caught the activity that was generated when switching between two large and complex windows. - Switching between multiple windows. This test caught the activity that was generated when switching between multiple windows in rapid succession. Results Following are the outputs of each test (the times are measured in seconds, and the network utilization in kilobits per second): awk -f awk.prg form.txt Total bytes: 240554 Total time: 34.92 Avg utilization: 68.89 kbps awk -f awk.prg entry.txt Total bytes: 281998 Total time: 96.70 Avg utilization: 29.16 kbps awk -f awk.prg switch.txt Total bytes: 25630 Total time: 6.65 Avg utilization: 38.54 kbps awk -f awk.prg switch2.txt Total bytes: 107276 Total time: 30.24 Avg utilization: 35.47 kbps ----- Phil Trubey SHL Systemhouse Inc. (Internet: phil@shl.com UUCP: ...!uunet!shl!phil) -- Phil Trubey SHL Systemhouse Inc. (Internet: phil@shl.com UUCP: ...!uunet!shl!phil)
Rudy.Nedved@RUDY.FAC.CS.CMU.EDU (03/11/91)
My apology if I don't understand the context of this but doing backups from a central machine has two parts. 1) If you are moving all the data to a central machine then you have a serious problem. 2) If you are controlling the backup process from a central machine then you don't have a problem assuming you have distributed tape drives per network "spur". -Rudy
kwe@BU-IT.BU.EDU (Kent England) (03/12/91)
Some people here in Information Technology at Boston
University set up a test to measure network load from one X terminal
doing specific X things. Here is an excerpt of what they did:
+------------+ +--------------+
| | | |
| diskful | | Visual |
| server | | |
| | | X19 turbo |
| | | |
+------------+ +--------------+
|| ||
=================================================================
||
subnet +--------------+
| |
| LANalyzer |
| |
+--------------+
They ran some test cases for a variety of X terminal
activities. The only traffic on the network was traffic from the X
terminal and the diskful server, including all X traffic and some NFS
traffic for diskless font service on the X terminal. The window
manager, twm, was running on the diskful server and not on the X
server. All X clients are running on the diskful server.
TEST pkts/sec kBytes/sec
maze 425 30
xterm tftpboot 303 92
twm:
move win 220 18
resize 220 18
hold button 220 18
plaid 220 17
ico 67 12
xbench 50 20
2 xtermwins cat'ing 45 23
xclock 0.0166-1 ~~
move mouse
out of win 3-5 pkts ~~
These numbers from the LANalyzer measure Ethernet frame data;
source and destination MAC addresses, protocol type field, user data
payload and CRC, but do not include the preamble or interframe gap.
For reference purposes, Ethernet at 10Mbit/sec can transfer
about 1,000 kBytes/sec of Ethernet data in maximum sized frames, after
subtracting the preamble and minimum interframe gap times. The
maximum number of Ethernet frames per second, assuming minimum sized
legal frames, is 14,880 frames/second.
These tests do not factor in the presence of routers between
the X terminal and server, nor do they account for the diskful server
load, given that the diskful server is bootloading, running all window
managers and all X client processes and all processes under the
clients (such as shells). These tests do not measure actual usage
patterns.
--------------------------------------
Those who really did the work:
Mike Amirault (ambi@bu-it.bu.edu)
Jason Heirtzler (jdh@bu-pub.bu.edu)
Chuck von Lichtenberg (chuckles@bu-it.bu.edu)