MacroPlacement
We implement Ariane design with 133 macros on the NanGate45 platform using the proprietary (commercial) tools Cadence Genus (Synthesis) and Cadence Innovus (P&R), and the open-source tools Yosys (Synthesis) and OpenROAD (P&R).
Macro Placement Generated by Cadence Flow-1
The screenshot of the placed and routed Ariane133-NG45 design generated using Flow-1 is shown below. Flow-1 uses Cadence Concurrent Macro Placer (CMP) to place the macros.
| Physical Design Stage | Core Area (um^2) | Standard Cell Area (um^2) | Macro Area (um^2) | Total Power (mW) | Wirelength (um) | WS (ns) | TNS (ns) | Congestion (H) | Congestion (V) |
|---|---|---|---|---|---|---|---|---|---|
| postSynth | 1814274 | 215401 | 1018356 | 751.379 | 3643746 | -2.976 | -12125.3 | ||
| preCTS | 1814274 | 241394 | 1018356 | 778.305 | 3731576 | -0.216 | -394.259 | 0.01% | 0.02% |
| postCTS | 1814274 | 245861 | 1018356 | 825.089 | 3779460 | -0.163 | -168.228 | 0.02% | 0.03% |
| postRoute | 1814274 | 245861 | 1018356 | 825.273 | 3917426 | -0.165 | -186.824 | ||
| postRouteOpt | 1814274 | 246221 | 1018356 | 825.631 | 3921486 | -0.165 | -167.579 |
Flow-2 Result for the Macro Placement Generated by Cadence Concurrent Macro Placer
The screenshot of the placed and routed Ariane133-NG45 design generated using Flow-2 is shown below. Here the initial macro placement is generated using CMP.
The following table shows the different metrics for Ariane133-NG45 (Utilization: 68% Clock Period: 1.3ns) implementation using Flow-2. | Physical Design Stage | Core Area (um^2) | Standard Cell Area (um^2) | Macro Area (um^2) | Total Power (mW) | Wirelength (um) | WS (ns) | TNS (ns) | Congestion (H) | Congestion (V) | |———————–|——————|—————————|——————-|——————|—————-|——–|———-|—————|—————| | preCTS | 1814274 | 251874 | 1018356 | 807.994 | 3885279 | -0.150 | -242.589 | 0.02% | 0.02% | | postCTS | 1814274 | 254721 | 1018356 | 851.977 | 3923912 | -0.127 | -133.426 | 0.04% | 0.10% | | postRoute | 1814274 | 254721 | 1018356 | 850.483 | 4049905 | -0.239 | -410.578 | | | | postRouteOpt | 1814274 | 256230 | 1018356 | 851.546 | 4057140 | -0.154 | -196.527 | | |
Macro Placement Generated by OpenROAD Flow Scripts (ORFS) (Flow-3)
The following screenshot shows the placed Ariane133-NG45 design generated using Flow-3. Here the macro placement is generated using the RTL-MP engine of OpenROAD.
Baseline Macro Placement Generated by Human
Manual macro placement on a gridded canvas
The following screenshots show the placed and routed Ariane133-NG45 design generated using Flow-2, where the macros are placed manually on a gridded canvas by Zhiang Wang.
The manual macro placement is provided in manual_floorplan.def.
We generate the manual macro placement in two steps:
(1) we call the gridding scripts to generate grid cells (in this case, we end up with a 22 columns x 30 rows grid); and (2) we manually place macros so that their centers lie on centers of grid cells, with no overlap between macros or overflow of macros beyond the layout canvas.
Note that this human-constructed macro placement can serve as a competitive baseline for Circuit Training. The metrics reported by the Innovus tool after different physical design stages are shown below. Note that (1) we set the activity factor to 0.2 in our flow; (2) the standard cell area does not include physical cells; (3) In order to match Nature paper, we adjust the pin positions to occupy about 60% of the left boundary; and (4) the total macro area for ariane133 (NanGate45) is 1018356um^2, and the overall utilization is ~68%%.
| Physical Design Stage | Core Area (um^2) | Standard Cell Area (um^2) | Macro Area (um^2) | Total Power (mW) | Wirelength (um) | WS (ns) | TNS (ns) | Congestion (H) | Congestion (V) |
|---|---|---|---|---|---|---|---|---|---|
| postSynth | 1814274 | 242813 | 1018356 | 759.332 | 4941086 | -0.764 | -451.478 | ||
| preCTS | 1814274 | 243778 | 1018356 | 791.963 | 4821642 | -0.119 | -137.735 | 0.06% | 0.08% |
| postCTS | 1814274 | 246360 | 1018356 | 835.687 | 4863282 | -0.115 | -50.599 | 0.06% | 0.13% |
| postRoute | 1814274 | 246360 | 1018356 | 834.281 | 5013763 | -0.121 | -74.638 | ||
| postRouteOpt | 1814274 | 246583 | 1018356 | 834.660 | 5018976 | -0.117 | -55.035 |
Macro placement generated by an industry engineer (not a gridded placement)
We thank Dr. Jinwook Jung of IBM Research for providing his Human Macro Placement of Ariane133 design as an alternative baseline. The following figure shows the placed and routed Ariane133-NG45 design, where the macro placement is generated by Dr. Jung. Dr. Jung has also provided his place_srams.tcl to reproduce the macro placement.
The following table shows the different metrics, when Flow-2 is used for the above macro placement. | Physical Design Stage | Core Area (um^2) | Standard Cell Area (um^2) | Macro Area (um^2) | Total Power (mW) | Wirelength (um) | WS (ns) | TNS (ns) | Congestion (H) | Congestion (V) | |———————–|——————|—————————|——————-|——————|—————–|———|———-|—————-|—————-| | postSynth | 1814274 | 244729 | 1018356 | 739.014 | 4664986 | -0.764 | -472.548 | | | | preCTS | 1814274 | 245069 | 1018356 | 792.784 | 4549848 | -0.133 | -175.54 | 0.03% | 0.20% | | postCTS | 1814274 | 247377 | 1018356 | 835.154 | 4567212 | -0.128 | -72.595 | 0.04% | 0.21% | | postRoute | 1814274 | 247377 | 1018356 | 833.294 | 4705687 | -0.143 | -86.669 | | | | postRouteOpt | 1814274 | 246722 | 1018356 | 831.745 | 4711746 | -0.107 | -69.589 | | |
Macro Placement Generated by Circuit Training (CT)
The following screenshot shows the placed and routed Ariane133-NG45 design generated using Flow-2, where the initial macro placement is generated by CT.
The following table shows the different metrics, when Flow-2 is used and the initial macro placement is generated using CT.
| Physical Design Stage | Core Area (um^2) | Standard Cell Area (um^2) | Macro Area (um^2) | Total Power (mW) | Wirelength (um) | WS (ns) | TNS (ns) | Congestion (H) | Congestion (V) |
|———————–|——————|—————————|——————-|——————|—————–|———|———-|—————-|—————-|
| postSynth | 1814274 | 244614 | 1018356 | 761.754 | 4884882 | -0.764 | -533.519 | | |
| preCTS | 1814274 | 244373 | 1018356 | 792.626 | 4732895 | -0.123 | -184.135 | 0.03% | 0.11% |
| postCTS | 1814274 | 247965 | 1018356 | 837.464 | 4762751 | -0.084 | -35.57 | 0.04% | 0.15% |
| postRoute | 1814274 | 247965 | 1018356 | 835.824 | 4887126 | -0.123 | -63.739 | | |
| postRouteOpt | 1814274 | 248448 | 1018356 | 836.399 | 4892431 | -0.09 | -57.448 | | |