1. Joint Commissioning (1) Data size issues Gene Flanagan Purdue University

2. Outline L2 stuff independent of L2CAL & L2XFT Data size limitation overview Individual systems –L2CAL –L2XFT Combined running & the data size question

3. General L2 progress 2 new PC’s –AMD opteron processors ( 2.8 Ghz) –Gentoo-6.1 operating system –gcc-4.1 compiler Validated with 3 store continuous running test (192.168.0.11) 2 nd pc (192.168.0.10) is been also used but never run continuously for 3 stores Comfortable with new pc’s (they are currently driving cdf from level 2)

4. Data volume limitations FILAR input FIFO 512 words deep Possible situation: –Multiple events reaching filar in close succession  If bus is busy with other channels – the input FIFO needs to buffer data, if volume is too large  will drop data  More likely at high lumi This problem has been observed at 240e30 when L2CAL & L2XFT are combined

5. Where does L2CAL data volume come from ? L2CAL software is designed to replace current clustering hardware Like the clustering hardware it requires all the trigger towers as input –576 trigger towers –Never send more then 576 towers (does not change with lumi)

6. L2CAL data inputs Data size (distributed over 4 filar inputs) Considered zero suppression but at high lumi little to be gained: –Moved to a 2tower/3word packing scheme –3 fibers x104 & 1 fiber x158 word pkts sent to pc (460 total independent of lumi) –If only L2CAL is included in system we don’t expect problems

7. Where does L2XFT data volume come from ? Stereo finder board sends phi pixels & slopes Empty pkt: –360 wds total (6 phi pixels X 1slope per cell) Non empty pkts (max # of words possible): –SL3- 240 cells (18 phi pixels x 5 slopes: 720words ) –SL5- 336 cells ( “” 1008words) –SL7- 432 cells ( “” 1296words) SL3 occupancy expected to be high at high Lumi

8. L2XFT data inputs (3 xft pulsars) Total xft data size can be ~1200 words @240e30 ~600 word (mean ) @ 240e30 @350e30 mean~800 & tails could be > 1500 Large data size could overflow the Filar input FIFO Need to solve this problem before We can have final combined system From Alison

9. Running L2CAL & L2XFT @ 240e30 Have found we can run either L2CAL or L2XFT (3 inputs) upto ~240e30 When they are run together ( with 3 xft inputs ) data corruption is seen The data corruption is on the XFT inputs

10. Reducing/Redistributing L2XFT data Main options that are up for discussion in next few talks: –Move from 3 xft pulsars to 6 xft pulsars –PC/Software- 2pc’s (one to buffer the xft data until needed ) –Reducing data volume directly at the source (stereo finder)/ special treatment of SL3 –Firmware to abort on level-1 inputs/ ROI (pulsar L2XFT receiver stage )