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Entry  22 Dec 2005, Konstantin Olchanski, Info, midas max event size? 
    Reply  23 Dec 2005, Stefan Ritt, Info, midas max event size? 
Message ID: 238     Entry time: 22 Dec 2005     Reply to this: 240
Author: Konstantin Olchanski 
Topic: Info 
Subject: midas max event size? 
My TPC events are fairly large: 18 FEC cards * 128 channels per card * 2 Kbytes
per channel = about 4 Mbytes. In my
frontend, when I request this event size, MIDAS complaints (in mfe.c) that it is
bigger than MAX_EVENT_SIZE, which
is set to 0.5 Mbytes in midas.h. What is the best way to deal with this? Should
we increase MAX_EVENT_SIZE to
something bigger? Remove the MAX_EVENT_SIZE limitation altogether?
For now, I increased the value MAX_EVENT_SIZE & co to (10*1024*1024) and it
seems to work (I also had to bump the
sanity check in bm_open_buffer() from 10E6 to 100E6). With 1/4 of the FEC cards,
the event size is 1 Mbyte at ~6
ev/sec the machine is almost idle, with the biggest CPU user being the event
builder at 10% CPU utilization.

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