( ESNUG 445 Item 3 ) -------------------------------------------- [05/24/05]
Subject: ( DAC 04 #42 ) Three Users Chime in about Prolific ProTiming Tool
> I have also looked at Prolific ProTiming. I feel ProTiming is good for
> engineers with a deficiency in their library and implementation flow.
> For us there was very minimal performance improvement with a huge
> amount of extra cells. Whereas, Zenasis can genuinely help you with
> their ZenCell technology.
>
> - Chetan Manharlal of Broadcom
From: Majid Rabbani <majid.rabbani=user company=nsc spot gone>
Hi, John,
I had a design where 40% of my paths had timing violations. ProTiming
optimized the design such that the cells with low drive strengths in
those violated paths were modified/replaced and timing was met. I didn't
do any power analysis though, so these cells (with larger drive strengths)
consume much power.
Can you believe it? 40% of my design (running at 500 MHz) had timing
violations and ProTiming fixed it?
The only drawback I've found in the ProTiming output is that clock trees
(after CTS during P&R phase) can have intolerable skew. This needs to be
fixed to be able to call it a complete timing optimization tool.
Fixing also depends on the cells in the technology libraries. If your
library doesn't fix violations, ProTiming can derive new library cells
from your technology library and fix them.
ProTiming uses scripts and performs optimization based on PrimeTime timing
reports. The only major addition to the design flow is the ECO route after
ProTiming optimizes your design.
- Majid Rabbani
National Semiconductor Oulu, Finland
---- ---- ---- ---- ---- ---- ----
From: [ Generals Gathered In Their Masses ]
Hi, John,
Anonymous please.
We have only one data point with Prolific, an ARM 9 in TSMC 90 nm with a
trial license. This ARM 9 has 30 K cells, 700 x 700 u x 7 routing layers.
Prolific boosted 1,582 cells
before Prolific: 2.802 nsec path .355 um2
after: 2.644 nsec .361
These times are from the flow:
Astro [Prolific ECO + ECO route] -> antennafix -> StarXT -> PT-SI
We only have Astro and hand tweaking as alternatives to ProTiming. We were
surprised that Prolific can improve on Astro so much; some designers would
kill for 100 psec. Note though that timing (path delay not slack) often
wobbles 10% through place, route, XTalk, Astro timing vs PT-SI...
The ProTiming tool setup was easy.
Doc fair-to-poor on how to drive it, background info for experienced users
would be useful. ("if you want to sell it you'll have to explain it.")
The general approach of coprocessing with Primetime is clever.
In short we're hoping to do more evaluation of Prolific on real chips;
that depends on price, time...
- [ Generals Gathered In Their Masses ]
---- ---- ---- ---- ---- ---- ----
From: Sudhir Chandratreya <schandratreya=user company=neomagic spot gone>
Hi John,
We taped out a design last year using Prolific's ProPower. This tool
automated swapping of high-Vt and low-Vt cells. We wanted to minimize
leakage power without losing our design's overall performance. We ran
two blocks through ProPower as a test so everyone was familiar with the
design and the tool. Then we got the real design ready for tapeout.
We had Prolific run ProPower on a final pass. Our SPR flow had reduced
the low-Vt instances to 3.7% of the total instances. ProPower switched
80% of those instances to high-Vt. That left less than 1% of the total
instances using low-Vt cells. ProPower ran for a couple of days, but we
didn't know how long it would take to finish. Stopped it and used an
intermediate result that reduced leakage power by 17%. The timing
remained unchanged. The design has been validated in silicon in 0.13 um
process and has not indicated any problem whatsoever with the use of
ProTiming.
- Sudhir Chandratreya
NeoMagic Corp. Santa Clara, CA
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