Preliminary Tests with multiple Database clients running over ATM

The system setup is shown below. The HP/UX system is a C200, running Objectivity v5.0. The data disk is a narrow SCSI device, rated at ~8 MBytes/sec. The ATM is on dedicated fibre (no other users), running at 155 Mbits/sec.

wpe1.jpg (23865 bytes)

Test 1: FTP of a large number of large files from the Exemplar to the C200 Disk.

ftp1.gif (21740 bytes)


Comment by Hugh Matlock: "It seems to me that the anomaly could be explained if the measurement system was not reporting results quickly enough. The disk IO and ATM counts could be accurate (as verified with FTP) but not available immediately to the "du -ks" or "atmmgr" utilities. Imagine, for example, that a low priority O.S. software process was used to copy and empty interrupt-level event counters. If this process was scheduled on a 1 or 2 second interval, then the counts available to the utilites would show pronounced spikes. Hope this helps..... "


The value of 47 for the cell size is confirmed for this payload by measuring the cell count for the ftp of a file of known size in bytes.

Test 2: CMS Event Reconstruction in one processor.

Reconstruction11.gif (27928 bytes)


Test 2: CMS Event Reconstruction in 16 processors.

Reconstruction161.gif (37447 bytes)



Other graphs are available for 2 clients, 4 clients, 8 clients.

If you have comments on, or insights into, the above, please send me email.