p 1TeV   5 event;   disk read overhead is ~ 5 sec
real	0m41.212s
user	0m20.561s
sys	0m0.179s

p 10 TeV  5 events
real	7m2.603s
user	3m30.825s
sys	0m0.184s

** same by 32 bit mode
real	6m25.253s
user	3m12.273s
sys	0m0.163s
*****************

&&& e 10TeV 5 events
real	8m16.640s
user	4m40.896s
sys	0m0.203s

*** && same by 32 bit 
real	7m55.028s
user	40m31.906s
sys	0m0.419s

