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How to obtain Congestion Statistics after Routing is complete?

Narasimhan
Hi, I am using SOC Encounter for the first time. I have done the placement and routing of a circuit using Encounter(with the help of a few tutorials). I want the congestion statistics of the design after the detailed routing is complete. On reading the User Guide, I understand that dumpCongestArea command gives the congestion statistics after the trial route or global route. I used the command after trial route to get the congestion statistics. It showed me negative values of remaining tracks. Then, I did detailed routing and used the dumpCongestArea command. The two files have the same data. But, if i try exporting the gds layout and do a post layout simulation on the circuit, it produces the correct output. Hence, I concluded that the circuit has been routed properly. So, there cannot be negative values of remaining tracks after detailed routing. Can someone explain me the procedure to get the congestion data of the design after detailed routing? Thank you. Lakshminarasimhan
Parents

  • Hello Vishnu,

     I need to obtain a histogram with congestion ratio on the x-axis and the number of nets with that much congestion in the y-axis. as shown below

    Congestion map

     In order to obtain this congestion map, I use the command,

     dumpCongestArea -all <filename>

    The file obtained gives me, the count of remaining tracks and total tracks of all cells. Example data shown below.


         Area              Density  remain/total tracks
    ---------------------------------------------------
    (0, 0) (15800, 16000) V: 19/20 H: 19/20
    (15800, 0) (30400, 16000) V: 17/18 H: 18/20
    (30400, 0) (34400, 16000) V: 5/5 H: 18/20

    I import this into a spreadsheet program and compute the congestion ratio as,

    congestion ratio = (Total tracks - remain tracks)/Total tracks

    From the values of congestion ratio, I obtain the histogram that was shown above.

    My problem is, this data obtained from dumpCongestArea is got after trialRoute. (dumpNanoCongestArea gives data after global route)

    But I need to draw a similar histogram after the detailed routing is complete. For this, I need information about the utilised to total tracks ratio(after detailed routing)

    Thank you.

     Lakshminarasimhan

    P.S:Also, I am trying to create a congested design, so that I can try tweaking the schematic and reduce the congestion. As a result, I have overflow after global routing, which is getting removed after detailed routing. So I am interested in the Congestion data after detailed routing. 

Reply

  • Hello Vishnu,

     I need to obtain a histogram with congestion ratio on the x-axis and the number of nets with that much congestion in the y-axis. as shown below

    Congestion map

     In order to obtain this congestion map, I use the command,

     dumpCongestArea -all <filename>

    The file obtained gives me, the count of remaining tracks and total tracks of all cells. Example data shown below.


         Area              Density  remain/total tracks
    ---------------------------------------------------
    (0, 0) (15800, 16000) V: 19/20 H: 19/20
    (15800, 0) (30400, 16000) V: 17/18 H: 18/20
    (30400, 0) (34400, 16000) V: 5/5 H: 18/20

    I import this into a spreadsheet program and compute the congestion ratio as,

    congestion ratio = (Total tracks - remain tracks)/Total tracks

    From the values of congestion ratio, I obtain the histogram that was shown above.

    My problem is, this data obtained from dumpCongestArea is got after trialRoute. (dumpNanoCongestArea gives data after global route)

    But I need to draw a similar histogram after the detailed routing is complete. For this, I need information about the utilised to total tracks ratio(after detailed routing)

    Thank you.

     Lakshminarasimhan

    P.S:Also, I am trying to create a congested design, so that I can try tweaking the schematic and reduce the congestion. As a result, I have overflow after global routing, which is getting removed after detailed routing. So I am interested in the Congestion data after detailed routing. 

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