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 Difference Between PLE, Spatial, Physical  

Last post Wed, May 16 2012 3:27 AM by grasshopper. 1 replies.
Started by sureshm 08 May 2012 10:33 PM. Topic has 1 replies and 3989 views
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  • Tue, May 8 2012 10:33 PM

    • sureshm
    • Top 500 Contributor
    • Joined on Wed, Feb 2 2011
    • Posts 21
    • Points 345
    Difference Between PLE, Spatial, Physical Reply

    Hi All, 

     Can some one be able to explain, the fundamental differences between PLE,Spatial, & Physical of RC flows and the advantages over the other. 

    In my View, 

    PLE, Only requires Cap Table as an additional input, which will be used to estimate the net RC from Cap table instead of LEF.

      How is the net length of the wire is calculated in this flow?? 

    synthesis -to_mapped 

    Spatial : It assumes PLE inputs + DEF. Documentation mentions It does some Placement of the block and thus minimize the net lengths .  How is the Net length of the wire is estimated here. 

    synthesize -to_mapped -spatial 

    However, The Above two Flows work Regular base RC License, RTL Compiler Ultra option, spatial option works with the EDI license availability. 

     Physical : This is Tricky. 

        It assumes all the inputs of Spatial. Documentation mentions that it does Post-placement Optimizations? 

       This Flow requires RTL Phys Advanced option to understand the detail placement of the placed cells. 

     

    My Question is what happens when i have the only RTL Compiler Ultra (RC200) license along with encounter executable pointed to the tool,  and still issue synthesize -to_placed. My understanding, it shouldn't work.  

    In my flow, the tool tries to check out for the advanced physical license, but failed to check out, yet did some optimization...! 

    What is the optimization it tried to do ? Did it merely did spatial flow???? 

    I have only issued the command synthesize -to_placed ?? !! 

    I am very much confused with the documentation ,as it is always never clear :) :)

     Please throw some light on this issue. 

    Thanks

    suresh 

     

    • Post Points: 20
  • Wed, May 16 2012 3:27 AM

    • grasshopper
    • Top 25 Contributor
    • Joined on Fri, Jul 18 2008
    • Chelmsford, MA
    • Posts 242
    • Points 3,205
    Re: Difference Between PLE, Spatial, Physical Reply

     Hi Suresh,

     I will take a stab at your questions

    PLE is intended to be a replacement and improvement over wireload models. They rely on die, cell (LEF + LIB), and technology process information. They are heuristic based and will not understand some of the placement related issues such as a detour route due to giant blockage in the middle of your die

     Spatial does not require any additional license beyond base RC and provides some physical awareness and related optimization. It is intended for fairly uniform placement and usually best suited for block level. It does not provide the full analysis and optimization capabilities of RCP but it does not require the license either

    RCP provides full analysis and optimization capabilities in a physical context

    RCP is only one that requires a special license. Neither PLE nor Spatial do. Question may be why not always run spatial and answer is it depends on flow and needs. Do you have a floorplan ? Do your challenges/technology warrant it ? Would your users be able to do something useful with physical feedback ?

    If synth -to_placed worked without an Adv Phys license, I personally would not be too trusting of those results. The way most licenses work is they get checked out when functionality is needed so it is possible in your case, it did some non-phys optimization and simply exited when it got to the physical part of things

     

    hope this helps,

    gh-

    • Post Points: 5
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Started by sureshm at 08 May 2012 10:33 PM. Topic has 1 replies.