[Technology Report]
45th DAC Takes The SoC Methodology Plunge
Come to Anaheim this June to get up to speed on the latest in ESL, physical design, analysis technologies, and verification, with a slant toward hands-on tutorials.
David Maliniak
ED Online ID #18943
May 22, 2008
Copyright © 2006 Penton Media, Inc., All rights reserved. Printing of this document is for personal use only.
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At the inaugural Design Automation
Conference in 1964, then known as the
SHARE Design Automation Workshop,
the fledgling design-automation
industry batted around some of the
fundamentals of its mission to engineers.
Papers carried titles such as “A
method for best geometric placement of
units on a plane,” and “New horizons in graphic output on the
IBM 1403 printer.” Some of that year’s program hinted at yet
unformed methodologies.
Now, as the EDA industry heads for the 45th Design
Automation Conference (DAC, Anaheim, Calif., June 8-12),
the focus is squarely on methodology. “In putting together this
year’s program, we relied on two years’ worth of attendee surveys
and feedback,” says Limor Fix, 45th DAC General Chair
(see “Anatomy Of A Conference Program” at www.electronicdesign.
com, Drill Deeper 18940). “People want more methodology-
oriented content and more ‘how-to’ with today’s tools. The
feedback was that there was too much future-oriented content
and not enough hands-on tutorial information.”
So in accepting some 20% of the 639 paper submissions,
DAC’s program committee forged a technical conference
heavy on the methodological aspects of areas that should
interest power users of EDA tools. Domains with the greatest
number of paper submissions include system-level design and
hardware/software co-design, physical design and manufacturing,
low-power design and power analysis, timing analysis
and design for manufacturing (DFM), and verification. All are
well represented in the program.
“These five broad areas provide a good indication of what
the industry is looking for and what academia is doing. It
shows where the focus and money is going,” says Fix.
SYSTEM LEVEL HEATS UP
The electronic system level (ESL) features a number of growing
areas for designers. One is the design of systems-on-a-chip
(SoCs) with multiple processors and the creation of parallelized
software to run on them (see “Software Rules The Day In
Multicore SoC Design,” Electronic Design, April 24, 2008, p. 38,
ED Online 18640).
Tutorials, panels, paper sessions, and invited papers at DAC
will present new ideas, state-of-the-art design tools, and novel
methodologies to reduce development time, reduce energy
consumption, and enhance system performance of these complex
designs and embedded parallel software.
Tools for power optimization at ESL have been emerging
for a few years now. At DAC, ChipVision Design Systems will
unveil two new ones for helping designers meet their power
budgets early in the design cycle.
One, dubbed PowerOpt, lets RTL and system designers
work interactively with system-level descriptions written in
ANSI-C, SystemC, and C++, exploring and visualizing critical
tradeoffs in timing, area, and power. It then implements their
choices to generate power-optimized, register-transfer-level
(RTL) code with up to three times lower power consumption
than RTL flows.
ChipVision’s second new technology to appear at DAC
is the P-SAM (Power Simulation, Analysis and Modeling)
framework. It offers system-level designers and software
developers a standards-based application
programming interface (API)
for source-code instrumentation, as
well as comprehensive analysis tools
for design descriptions in SystemC
or pure C/C++. It also enables early
system-level power analysis based on
system-level simulation.
Working interactively, PowerOpt
and the P-SAM framework perform
architectural, software, and power
tradeoff analysis at a level not typically
possible with other approaches
(Fig. 1). Users can investigate various
bus topologies, compare power consumption of intellectual-property (IP) blocks, identify hotspots,
and explore other system areas to hone their power-management
strategies and verify these are met.
Both PowerOpt and P-SAM are available now. PowerOpt
costs $450,000 for a three-year, time-based license. P-SAM pricing
varies depending on the SoC’s structure.
HIGH-LEVEL SYNTHESIS GROWS
Another product that can provide gains in power management at
ESL is version 3.4 of Forte Design Systems’ Cynthesizer SystemC
synthesis tool. Cynthesizer 3.4 adds integration with a poweroptimization
tool.
Power-estimation reports generated by the power-optimization
tool are included in the results available with the Cynthesizer
Workbench, Cynthesizer’s graphical interactive analysis environment.
These reports, cross-linked to annotated source-code views,
make it easy to understand implementation tradeoffs and make
changes for improved quality of results (QoR).
Given the increased interest among designers in FPGAs, it’s
only logical that high-level synthesis should make its way to
FPGA flows. At DAC, Synfora will show its PICO Extreme
FPGA and PICO Express FPGA algorithmic synthesis tools.
The PICO Extreme FPGA makes it possible to implement
dramatically larger and more complex subsystems using a recursive
system-composition methodology. It allows for familiar
design styles, reduces runtime, and achieves high QoR in implementing
video codecs, wireless modems, or imaging pipelines.
PICO Extreme’s recursive system-composition methodology
is enabled by tightly coupled accelerator blocks (TCABs) that
allow users to designate parts of their algorithm as custom
building blocks.
PICO Express FPGA is a flavor of the tool optimized specifically
for Xilinx’s 65-nm Virtex-5 and Spartan-3A DSP FPGAs.
All products are currently available. PICO Extreme starts at
$350,000, while PICO Express FPGA starts at $150,000.
Standards in the ESL realm continue to evolve, and DAC will
be the venue for the Open SystemC Initiative’s (OSCI’s) rollout
of the final version of TLM 2.0. This standard enables SystemC
model interoperability and reuse at the transaction level, providing
an essential ESL design framework for architecture analysis,
software development, software performance analysis, and hardware
verification.
Continue to page 2
Expected changes to the final version of TLM 2.0 include
unified interfaces for loosely timed and approximately timed
modeling styles, as well as enhanced support for extended protocol
definitions using the generic payload. OSCI is currently
developing a TLM-2 language reference manual (LRM) that
should be completed by the end of 2008. This OSCI LRM will
then be used to drive the IEEE standardization process.
DFM REMAINS A CONCERN
DFM remains a growing niche in EDA. At DAC, tutorials, panels,
and paper sessions will discuss the current integration of DFM
tools into the design flow and their anticipated impact. There will
also be a comprehensive review of variation in manufacturing and
the available analysis and optimizations at all levels of the design,
starting at the architecture/microarchitecture levels. New techniques
in OPC-aware (optical-proximity correction) routing and
new ways to consider circuit performance during mask preparation
will be presented, too.
Now that SoC design work is heading toward the 45- and
32-nm nodes, OPC and subsequent verification become much
more compute-intensive. Unfortunately, the growth in CPU
power isn’t keeping up with this trend.
Gauda Inc., a Sunnyvale, Calif.-based startup, will be at DAC
with technology that can accelerate OPC and optical-proximity
verification (OPV) up to 200 times faster than competitive technologies,
according to the company. The acceleration is achieved
without any specialized hardware or FPGA clusters.
Rather, Gauda’s approach involves a new breed of algorithms
using CPUs and GPUs that are traditionally found in gaming systems.
With Gauda’s technology and about 10 garden-variety desktop
PCs, a large, full-chip 45-nm layout can be processed overnight
(Fig. 2). OPV can be accomplished on a single desktop CPU.
In stealth mode since 2005, Gauda has now demonstrated
that its technology is linearly scalable to several hundred desktop
machines. This makes it possible to complete OPC and/or OPV
runs in a few hours.
One potential way to address DFM problems is with layout
optimization. To that end, Takumi Technology Corp. will
be showing its Enhance-RO layout optimization tool, which
addresses both rule- and model-based issues that increasingly
impact parametric and catastrophic yields at deep sub-wavelength
process nodes. With its built-in cost analysis and dynamic
tradeoff analysis, the tool lets users enforce all applicable recommended
rules by objectively trading off against cost.
A MATTER OF TIMING
Coping with variation is a critical concern in recent designs.
Thus, DAC will offer tutorials and paper sessions on how to take
variation into consideration. For example, delay predictions in critical paths often have significant errors,
and when silicon is measured, there’s a large
variation of path delays. To combat poor
timing estimates, new technologies will be
presented that use early silicon data to tune
and correct the predictions.
Timing-constraint files are getting so
large that ensuring the constraints’ validity
becomes very time-consuming and
error-prone. Blue Pearl Software will bring
to DAC its Azure Timing Constraint
Validator, a tool that automatically validates
timing exception constraints at all
stages in the flow, from RTL to final
netlist. With it, designers can automatically
check the constraints used to direct
synthesis, static timing analysis, and placeand-
route tools.
Azure Timing Constraint Validation
is based on state-space search technology
as opposed to tools based on formal
verification using combinational analysis
techniques. These techniques can’t validate
multi-cycle paths and result in the incorrect reporting of paths
that are sequentially false, the company claims. The tool is available
now for a one-year, time-based license price of $95,000.
Testing of deep-submicron SoC circuits at RTL is made
substantially more difficult by the proliferation of at-speed
faults, which are undetectable with traditional stuck-at testing.
At-speed defects need to be detected by generating tests with
new fault models.
Atrenta’s SpyGlass-DFT DSM, which will be shown at DAC
for the first time, is touted as the only tool available for early
fault-coverage estimation and analysis for timing closure on functional
clocks due to at-speed test (Fig. 3). It generates at-speed
test rules to help resolve timing-closure issues upfront at RTL. It
also predicts at-speed test coverage early at RTL as it pinpoints
and diagnoses low coverage issues.
THE PHYSICAL REALM
Today’s large SoCs require physical-design decisions to be based
on multidimensional considerations. At DAC, paper sessions
will discuss how to optimize voltage partitioning using floorplan
and application information. There will also be presentations
on an analytical placer that will produce better results using
routability considerations.
Atoptech will exhibit for the first time at DAC with its Aprisa
physical-design suite. In addition to demonstrating Aprisa’s
netlist-to-GDSII capabilities, Atoptech will also focus on detailing
the tool’s True-timing analysis and low-power benefits.
True-timing provides signoff-quality timing during place and
route, says Atoptech. As a result, relying on timing estimates
won’t cause you to over-optimize the design or require significant
manual efforts to close timing. Aprisa provides modes to match
either Synopsys’ PrimeTime-SI or Cadence’s CeltIC timing
analyzers. Signal-integrity analysis is very fast and multithreaded.
CCS model support for even greater accuracy
(within 5% of Spice) is also available.
DAC will see the launch of Magma
Design Automation’s Talus Hydra floorplanner
and hierarchical design planner,
a tool that’s fully integrated into Magma’s
RTL-to-GDSII flow for managing the
complexity of achieving timing closure in
multimillion-gate designs.
Continue to page 3
Talus Hydra anchors a full hierarchical
methodology that supports bottom-up,
block-based flows, top-down black-box
flows, and mixed flows with automated
floorplanning, partitioning, and time budgeting.
It enables early design planning
using a netlist consisting of a mix of gates,
RTL, macros, black-box models, and
GlassBox models. It affords quick feedback
on design prototypes for floorplan,
design, and timing-constraint refinement.
Ciranova plans to show its Helix tool.
It’s an automated analog layout suite that
optimizes both circuit and device layout
simultaneously, delivering design-rule-correct placement comparable
in quality to that produced by an experienced layout
designer, claims the company. Using Ciranova Helix, analog and
custom designers can explore multiple layout alternatives in minutes,
allowing them to get higher-quality designs to market in a
fraction of the time needed by conventional methods.
With Helix’s fast runtimes, designers can explore multiple
layout alternatives and even extract parasitics early in the design
process. Benchmark results include placement of a 154-transistor,
phase-locked-loop (PLL) circuit in under four minutes.
Ciranova Helix’s primary inputs are a Spice netlist and a
Process Design Kit (PDK) containing either Cadence SKILL
PCells or Ciranova PyCells, such as those in the Interoperable
PCell Library (www.iplnow.com). Helix is a native OpenAccess
tool, which integrates seamlessly into OpenAccess-compatible
environments such as Cadence’s Virtuoso, Silicon Canvas’
Laker, and Magma’s Titan, as well as DRC tools like Mentor
Graphics’ Calibre and Synopsys’ Hercules. Ciranova Helix is
available now.
GOING FOR LOW POWER
DAC is the place to be this year for low-power designers, with tutorials,
paper sessions, and several workshops delving into the how-to’s
of designing low-power SoCs. Minimizing SoC power consumption
has become a prime design goal, especially for multiprocessor
SoCs, where peak temperature limits are of high concern.
Sequence Design is planning to show its PowerArtist tool,
which focuses on power reduction at RTL in three key areas:
clocks, memory, and datapath. The tool’s analysis engines examine
the design’s RTL code, prioritize design hotspots, and deliver
power reduction in one of two ways. It can operate in automatic
mode or guide the user through manual edits within a graphical
user interface (Fig. 4).
PowerArtist can be integrated with all design flows, including
synthesis and formal verification. It’s also compatible with
OpenAccess databases through its open API. Pricing starts at
$220,000 for a one-year time-based license.
An interesting entry in the low-power design arena is Envis,
formerly known as Envision Technology. At DAC, Envis will
display its range of tools for measuring and reducing power consumption.
For the power-estimation side of the equation, Envis’
Kelvin performs automatic power-pattern generation. The tool
takes in a netlist and generates vectors to estimate power consumption
for that netlist. The estimates are realistic, correlating
well with average power.
Interfacing through an API with any of the industry-standard
simulators, the tool’s vectors can be used to generate average
power estimates as well as detailed power-pattern data. Estimates
can be made early in the development cycle, when designers are
trying to choose between IP blocks for a given function.
For power reduction, Envis offers up its Chill tool, described
as a next-generation approach to clock gating. The tool automatically
partitions the circuit into power partitions that can be
turned on or off together. It inserts activity-detection circuitry
that determines when a partition is inactive and disables clocking
to that partition.
Clock gating can be done in combinational or sequential
fashion. If manual clock gating has already been imposed on the
circuit, the tool won’t override it. Instead, the tool optimizes it.
Working together, the Kelvin and Chill tools comprise a
powerful methodology for estimating and reducing power consumption.
After synthesis, a Kelvin run on the netlist establishes
a baseline estimate before running Chill. A second Kelvin run
estimates the power savings achieved by Chill. Kelvin can be run
again after physical design for an even more accurate estimate
that includes parasitics. Both Kelvin and Chill are available now.
Chill sells for $180,000 for a one-year, time-based license, while
Kelvin sells for $50,000.
An increasing concern for power designers is the interaction
between their ICs, the packages they reside in, and the circuit
boards they’re attached to. A systemic approach can reduce
design risk and optimize system cost. To that end, Apache
Design Solutions will be at DAC with its Sentinel-PI, a chippackage-
system co-design tool for power integrity. Sentinel-PI
provides modeling, analysis, and optimization for IC, package,
and printed-circuit-board (PCB) designers.
Sentinel-PI generates Spice-accurate models of the full-chip
power-delivery network, which Apache terms Chip Power
Models (CPMs). The models contain parasitics of the nonlinear
switching and non-switching devices, as well as decoupling
capacitance, loading capacitance, power/ground coupling capacitance,
and effective RCs. This latest release of CPM adds inductive
effects for higher accuracy.
VERIFYING ABOVE RTL
To address the current gaps in functional verification, designers
are raising the abstraction level of design entry. At DAC this
year, we will learn about advances in functional verification of
these abstract SystemC/C++ models. In particular, there will be
presentations covering both simulation and formal verification
techniques, with special focus on handling concurrency.
Verification above RTL may be appealing, but designers can be
stymied by the lack of model availability. Where do models come
from? And how long do they take to create? At DAC, Carbon
Design Systems will demonstrate a speedier version of its Carbon
Model Studio, a tool for automatic generation, validation, and
implementation of hardware-accurate software models.
The upgrade of Carbon Model Studio includes a key debug
improvement that provides increased visibility into complex
design constructs. It offers full visibility into named and
unnamed generated blocks, VHDL composite types, and multidimensional
arrays, including nested arrays and composites.
In addition, Carbon Models have new API calls for accessing
design constructs.
With improved model validation,
designers can control the model-validation
generation process from inside
Carbon Model Studio through a new
component editor. The Model Validation
component’s mixed-language shadow
hierarchy matches that of the original
design for tighter integration into complex
testbenches, assertion languages,
and custom validation environments.
Carbon Model Studio, shipping now,
is available for Solaris and PC platforms
running Linux and Windows. Pricing
for the complete model-generation and
execution environment is “use-model”
dependent and starts at $20,000.
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