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Joint Commissioning (1)

Joint Commissioning (1). Data size issues Gene Flanagan Purdue University. Outline. L2 stuff independent of L2CAL & L2XFT Data size limitation overview Individual systems L2CAL L2XFT Combined running & the data size question. General L2 progress. 2 new PC’s

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Joint Commissioning (1)

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  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) • 2nd 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) From Alison • 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

  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 )

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