NERSC 1998 User Survey Results - Summary

Question 28. Comments about NERSC's large scale computers, suggested improvements, future needs (all responses here)

15 respondents commented on the T3E, 9 on PVP systems, and 8 provided suggestions for the next machine.

T3E Queue Related Comments:

4 need T3E queue structure adequate for large-scale problems (longer queues)
2 longer T3E queues for smaller PE amounts (64)
1 T3E turnaround time poor & hard to predict when job will finish
1 too many small jobs on T3E
1 would like to use T3E as a small user
1 T3E scheduler needs improvement: too many idle PEs

Other T3E Comments:

3 T3E praised for great I/O access time, fast communications
1 better T3E I/O (increase number of files open simultaneously)
1 don't like how T3E maps problem onto nodes; most MPPs can take advantage of local communications (nCube, Paragon scale better than T3E)
1 more inodes on the T3E
1 more T3E memory (or better memory management)
1 better 32-bit support for T3E
1 want Cray to continue improving T3E

PVP Comments:

3 want PVPS with more CPU, memory, disk, bandwidth
1 more PVP cycles
1 more interactive PVP CPUs (killeen not enough)
1 better J90 queue structure; management as unit
1 too slow for large (64 mw) PVP jobs; give more weight to large memory jobs
1 need much more memory for C90 class machines; the SV1 should have a lot
1 more disk space on PVPs

Comments about the Next Machine:

2 need at least 1 TB memory for next machine, more memory on T3E or successor
1 worried that performance is meaningless when considering next machine since sustained MPP performance poor compared to peak and likely to get worse
1 more T3E nodes or another parallel machine (mostly would like a much larger T3E)
1 need more, faster computers (needs more CPU speed than memory or I/O)
1 need to do more research on I/O and total memory
1 only need NERSC for parallel computing; do all else on desktop
1 future machine needs CPUs capable of reaching half of peak
1 future machine should take into account mapping of problem onto CPUs

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