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

 
Michael,

we need to answer Stu's question.


-----Original Message-----
From: owner-sv-ec@eda.org [mailto:owner-sv-ec@eda.org] On Behalf Of
Stuart Sutherland
Sent: Wednesday, February 14, 2007 2:58 PM
To: 'Michael Rohleder'; 'Clifford E. Cummings'
Cc: sv-ec@eda.org; sv-ac@eda.org; sv-cc@eda.org
Subject: [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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