( ESNUG 348 Item 3 ) --------------------------------------------- [3/30/00]
Subject: ( ESNUG 346 #1 ) Married Guy Busted; It Was PKS That Was Broke !
> I've worked in layout automation and chip design for over 10 years. Of
> all the engineers I know working _physical_ design on ASICs & processors,
> most won't even look at PhysOpt because they don't want to correlate a
> placement engine that doesn't have its own router (making me wonder how
> PhysOpt even qualified in the GDS II category since it can't get to
> polygons under its own steam). It seems to me that lack of a router in
> PhysOpt leaves alot of heavy lifting to the Avanti/Cadence/IBM back-end
> flows (try notch-filling, antenna checking, and cross capacitance, for
> instance!)
>
> I'm not talking out of my ass here, John. We looked at PhysOpt. We
> couldn't even get PhysOpt to run -- but that may be more symptomatic of
> where we are on the Synopsys support/sales pecking order than the actual
> quality of the tool.
>
> - [ Tony, the Tiger ]
From: [ Tony, the Tiger ]
Hi John,
As most married men can tell you, to stay married I learned very quickly to
say the words "I'm sorry, Honey, it's all my fault" when I screw up. This
is one of those times. The Synopsys guys are gunna love this, I'm sure.
It's time for [ Tony, the Tiger ] to eat some sugar-frosted crow.
In my company, I'm the guy who's supposed to make sure our design flows
can hit timing on schedule. That's why I wrote you arguing that I'm not
seeing the kind of data in my evaluations showing that any of the next
generation physical synthesis solutions has a definitive advantage over our
tuned "DC with Avanti/Cadence timing-driven placement" flow. I'm as game
as the next guy to bring a new tool up if I can see where it makes a real
difference. So far what I'm seeing is a lot of people with crappy flows
flocking to this year's version of EDA Viagra. The kind of designs I see
falling flat in solid timing-driven flows wouldn't cut the mustard in _any_
flow because of fundamental design errors (usually timing constraints so
poorly authored they may as well have been done with spray paint). Every
design we've done with solid constraints up-front closed. Those without,
went down in flames. Without solid constraints, no tool is going to do
squat for you on timing. If you've got the right constraints, I can close
it with the DC + timing-driven placent flow I've got today.
In my letter I wrote:
"We looked at PhysOpt. We couldn't even get PhysOpt to run -- but that
may be more symptomatic of where we are on the Synopsys support/sales
pecking order than the actual quality of the tool."
I mixed PhysOpt up with PKS, both of which were written off early in
our evaluation, but for vastly different reasons. The simple fact is that
neither I nor any of the design teams I support got our hands on PhysOpt.
We called Synopsys some months ago but nothing came of it. Unfortunately,
at that same time, I was talking to Cadence about using PKS on one of our
designs as a test case. It turned into what you called a taxi-cab eval,
John. Cadence took our test design to run through PKS and disappeared for
many moons. Repeated follow-up calls kept getting lame answers that I could
only interpret as "Gosh, Tony, our PKS results are too pathetic to show
you." In my mind, I wrote both of them off. So, I must humbly eat crow
and say that when I mistakenly said "PhysOpt didn't work," I was actually
thinking of my "PKS didn't work" experience. In my mind, I confused the
Cadence PKS no-show w/ our simultaneous Synopsys PhysOpt talks.
So, in the same tone I use with my wife when I mess up, I must say I humbly
apologize for my mistake here. Sorry for trashing PhysOpt when, in my
heart, I had meant to trash PKS. At least I don't have to buy you guys
flowers...
- [ Tony, the Tiger ]
P.S. But I still stand by my original argument: this physical synthesis
crap isn't showing drop-dead results against the tuned "DC w/ timing-
driven placement" flows I have today. Why bother with them???
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