[sv-ec] RE: [sv-cc] PDF version of clean Scheduling Proposal

Michael,

I agree that a Pre-Observed region could be useful.  I would like
clarification on the wording:  

>  - it has similar semantics than the Pre-Active region, in 
> particular it 
> can not schedule any
>    event into the same time step (there is no path back to the Active 
> region).

This implies, but does not explicitly state, that the Pre-Observed region
could schedule an event in a future time step.  If so, the region in the
future time step in which the event is scheduled should be specified.  I
cannot be a future Pre-Observed region, since that has no feedback path.

I haven't looked, but there may be a similar ambiguity about where future
events are scheduled by PLI routines called from any other region other than
the Active region.

Stu
~~~~~~~~~~~~~~~~~~~~~~~~~
Stuart Sutherland
Sutherland HDL, Inc.
stuart@sutherland-hdl.com
503-692-0898
 

> -----Original Message-----
> From: owner-sv-cc@server.eda.org 
> [mailto:owner-sv-cc@server.eda.org] On Behalf Of Michael Rohleder
> Sent: Wednesday, February 14, 2007 10:31 AM
> To: Clifford E. Cummings
> Cc: sv-ec@server.eda.org; sv-ac@server.eda.org; sv-cc@server.eda.org
> Subject: Re: [sv-cc] PDF version of clean Scheduling Proposal
> 
> Hi Cliff,
> 
> many thanks for sending this.
> 
> This email contains some feedback about this document, and it 
> is split 
> into an official part
> (discussed within SV-CC) and a second part containing just 
> feedback from 
> myself.
> 
> *Official part:*
> After reviewing the current proposal I have raised the 
> request to add an 
> additional PLI
> region (proposed name Pre-Observed) that has the following behavior:
>  - it is a PLI-only region
>  - it is called immediately before entering the Observed region
>  - it has similar semantics than the Pre-Active region, in 
> particular it 
> can not schedule any
>    event into the same time step (there is no path back to the Active 
> region). I am not sure
>    what is the best phrasing here; the one in the Preponed 
> region might 
> be too restrictive ...
> 
> We have discussed this within SV-CC and this request has been 
> accepted 
> by the committee.
> 
> The reason for this request is that I believe a callback is 
> required and 
> useful when the
> design has fully settled, but there is not yet any activity 
> created by 
> the testbench
> or assertion side. Post-NBA is not useful, because you don't know 
> whether this is the
> last iteration of the 'inner' design loop. Post-Observed is 
> not useful, 
> because the assertions
> may have created new events already. This new region must not 
> create new 
> event for the
> same time step to avoid situations where two tools are fighting to be 
> the last one invoked
> after the design has settled.
> 
> I hope this is sufficient. Let me know when you want to have 
> an update 
> in the official format.
> 
> *Second part:*
> 
> There was some focus on creating a consistent naming of the regions. 
> However I don't understand
> why the region "Reactive" was not renamed to be "Re-Active". 
> All regions 
> but this one use the Re-
> prefix. I am not really religious here, but this looks 
> interesting to me.
> 
> That's all.
> 
> Best regards,
> -Michael
> 
> 
> Clifford E. Cummings wrote:
> > Sorry -
> >
> > I meant to send the PDF version of the clean event scheduling 
> > proposal. Attached.
> >
> > Regards - Cliff
> >
> > ----------------------------------------------------
> > Cliff Cummings - Sunburst Design, Inc.
> > 14314 SW Allen Blvd., PMB 501, Beaverton, OR 97005
> > Phone: 503-641-8446 / FAX: 503-641-8486
> > cliffc@sunburst-design.com / www.sunburst-design.com
> > Expert Verilog, SystemVerilog, Synthesis and Verification Training
> >
> 
> 
> 
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> 
> 



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