New accounting policy for SP6

[HPC-News]

Dear users,
Starting from next July 2010, the new ISCRA projects (iscra.cineca.it) will start running on the SP6 machine in CINECA.

For old projects and agreements the old budgeting rules will be maintained, while for the new ISCRA grants they will be completely modified:
instead of actual cpu time, the billing will be based on elapsed time and the effective number of cores (reserved, not used!) by the batch job. 

These new rules, which are already applied in most if not all computer centres, are fairer for users because they discourage the submission of jobs reserving large numbers of resources (e.g. cores or memory) but which in the end aren't actually used.

In particular on SP6, if you require a memory per task larger than the "average" memory (3.4G per core or 1.7G per cpu), this will result in a bigger request in terms of number of cores and in a possible dramatic increase of the cost of your job.

In order to help you to better understand the real requirements of a job, starting from now, a rough analysis is being  printed at submit time:

=== job requirements ===
core/cpu usage:         cpu (SMT)
Total tasks:            1
Threads per task:       1
Memory per task:        50 MB
Total cpus:             1
Total memory:           50 MB
Total cpus reserved(considering memory request): 1

The meaning of this table should be easy to understand. 
It is important to pay attention to the last line ("Total cpus reserved"). If it is higher than "Total cpus", please check your memory request and verify if you really need it.In the next future the cost of your job will depend on "Total cpus reserved" !!!
(more information about the new billing rules will be posted soon on this mailing list. Be tuned!) 

Regards,
Elda Rossi
HPC User Support

Sent by: Elda Rossi