Strange! What's the difference between core utilization ratio and core row utilization ratio?

Discussion in 'Cadence' started by walala, Oct 7, 2003.

  1. walala

    walala Guest

    Dear all,

    I am design with Silicon Ensemble P&R:

    The floorplan is of size 2400x1800, flip + abut, I am changing row spacing:

    Can experts take a look at these changes, and give me some comments:
    particularly, I don't know why row spacing play such important row, and for
    case 1), row spacing = 0 track, along with flip + abut, it should be very
    good, but why it has so many violations after WROUTE? Then I increased row
    space = 1 track in case 2), and the violations drastically reduced to 0 in
    WROUTE, but still there is one open in CONNECT RING; so I think increasing
    row space is good, but then I try case 3), row spacing increases to 2
    tracks, now the result is even worse, there are 37 violations remaining
    after 29 search and repair pass in WROUTE; and the opens in CONNECT RING
    increased...

    You see, it's so strange to try out those combinations of numbers,... there
    are so many things need to try, I have been doing these blindly in the past
    one month. My best result is 0 violations, 1 open in CONNECT RING, and about
    40% utilization ratio. Can you solve that OPEN problem? Can I do better in
    terms of utilization?

    Can any experts here give me some help?

    Thank you very much,

    -Walala

    Case 1) row spacing = 0 track:
    FINIT FLOOR rowu 0.85 rowsp 0 blockhalo 2000 f x 240000 y 180000 abut xio
    300
    0 yio 3000 ;
    FINIT FLOORPLAN rowu 0.85 rowsp 0 blockhalo 2000 f x 240000 y 180000 abut
    xio
    3000 yio 3000 ;

    Results:
    core row utilization = 35.72%
    core utilization = 85.00%
    201 rows
    2 opens when connect ring
    WROUTE first pass 16797 violations remained, auto stopped

    More strangely, if I arbitrarily change the rowu 0.85 to 0.5 in the above
    command, the core row utilization = 35.72% doesnot change, instead, the core
    utilziation changed from 85% to 50%....(which is against my belief, because
    I thought "rowu" means row utilization, and not the core utilization...)

    Case 2) row spacing = 1 track:
    FINIT FLOOR rowu 0.85 rowsp 96 blockhalo 2000 f x 240000 y 180000 abut xio
    30
    00 yio 3000 ;
    FINIT FLOORPLAN rowu 0.85 rowsp 96 blockhalo 2000 f x 240000 y 180000 abut
    xi
    o 3000 yio 3000 ;
    Results:
    core row utilization = 39.67%
    core utilization = 76.57%
    181 rows
    1 opens when connect ring
    WROUTE 0 violations remaining, after 14 search & repair, first pass 6486
    viola
    tions,

    Case 3) row spacing = 2 track:
    FINIT FLOOR rowu 0.85 rowsp 192 blockhalo 2000 f x 240000 y 180000 abut xio
    3
    000 yio 3000 ;
    FINIT FLOORPLAN rowu 0.85 rowsp 192 blockhalo 2000 f x 240000 y 180000 abut
    x
    io 3000 yio 3000 ;
    Results:
    core row utilization = 43.78%
    core utilization = 69.66%
    165 rows
    3 opens when connect ring
    WROUTE 37 violations remaining, after 29 search & repair, first pass 6385
    viol
    ations,
     
    walala, Oct 7, 2003
    #1
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