( ESNUG 482 Item 10 ) ------------------------------------------- [06/15/09]
Subject: One engineer compares using vs. not using Data Management tools
From: [ The Wolverine ]
Hi, John,
Please keep me anon.
At DAC 2007 we went shopping around for design data management systems. We
looked at IC Manage, Dassault/Synchronicity, and ClioSoft. (Prior to that,
for DM we used GNATS plus an in-house set of scripts we called "DITTO".) At
that DAC, we found that all three of the commercial DM tools had basic
revision control and a Cadence interface, plus:
- IC Manage had better check-in control for a group of files (all or
nothing). This means that if there was a network failure during
the check-in process, none of the files were checked in and IC Manage
displayed an error and did not record a change in the library. Clio
and Synch seemed to perform the check-in process on a per file bases,
so if the same network failure occurred, the library would record a
change without having all the files checked in. (Not good.)
- DM is all about linking releases to a chip. This visibility is key
because 1 year down the line, you change; you need to see what
changed in the libraries.
- IC Manage let you do automatical bidirectional library updates between
designs and integrated libraries (parent/child). While at DAC 07,
ClioSoft nor Synchronicity couldn't do this.
We chose to buy IC Manage to replace our old DITTO set of scripts. In the
past year, we have used IC Manage GDP on 3 full custom analog and digital
production designs, plus multiple derivative designs. We use it for our
RTL design (Synopsys DC and VCS) and for physical verification (Mentor
Calibre and Cadence Virtuoso).
Here's what we saw switching from our home grown DM to using IC Manage:
> So for any given project, there's a roughly 50-50 chance some sort of DM
> issue will burn you and it's set you back, on average, 16 work days.
>
> - from http://www.deepchip.com/wiretap/090513.html
Our delays due to DM issues were at least 16 work days, too. Our DITTO was
based on increasing revisions, and unfortunately, wasn't foolproof. It
didn't stop our people from updating old revisions, and they would end up
changing more than they planned. Our engineers would be simulating at the
top level, realize there was a problem, and then waste literally weeks
trying to track down the bogus discrepancies.
We have a centralized flow, and I am in charge of back-end chip integration
and layout. With IC Manage, I only spend 3 hours a week managing project
set up and release creation for all our projects. It takes 2-4 hours for me
to use the IC Manage Project Manager (ICMPM) for a new design -- once I do
that, the entire design team is ready to go. Not bad considering that our
typical design cycle is 6-9 months for a new design and 3-4 months for a
derivative design.
Integration into our flow
IC Manage uses its own library manager which looks almost exactly the same
as Cadence's default Virtuoso library manager; so it's a pretty transparent
part of our flow. It's fairly straightforward and can be learned in their
2 hour training session -- plus I put together a 20 minute internal video
for my team. The IC Manage-Cadence interface gives my guys:
- Access to extra icons and version information
- Buttons to do simple and hierarchical design check-ins and check-outs
- History of the cell, view, file or library
- Ability to manage different cell views (schematic, layout)
individually or as a group
- A widget for design synchronization.
DC, VCS and Calibre are file-based, so we use IC Manage's visual client to
manage and revision their files.
During our DITTO days, each designer would have to make their own copies of
the design files and recopy them back into the master library. A common
DITTO user error was from copying but not properly updating reference libs.
The designers would promote their designs into the golden library. We had
one guy in charge of the golden library who would make sure of the design's
integrity. Once the golden library guy updated the library, the other
engineers would verify their own designs from it. We did the re-synching
ourselves with our remote site.
The problem with DITTO was that we could be out of sync, even though we had
set up a chron job and automatic updates at intervals.
With IC Manage, everything is on-demand and designers can synch up all data
immediately. All the designers work from the same libraries; they do design
check-in and check-out and can see the status.
Verification
With DITTO, we used a detached bug tracking system (GNATS) for tracking and
fixing bugs. When we found bugs, whoever was in charge of the engineering
change notices would need to follow-up, implement the change, then have to
make sure to close the ticket.
IC Manage has integrated bug tracking, with Bugzilla, Jira, and Trac built
in. So now we do bug tracking right from the IC Manage-Cadence interface,
which saves us the extra effort of having to go outside the Cadence system.
(The last time we looked at ClioSoft and Dassault/Synchronicity, they just
offered APIs, so we would have had to install and set up bug tracking and
link it into revision control ourselves.)
IC Manage tracks the design configuration, releases and file versions, and
provides a mechanism to close a defect directly from the Cadence library
manager. We can quickly isolate the bug, verify it is fixed, provide
releases and propagate the fix to all impacted derivatives as needed. This
same process applies not just to bug fixes but also to enhancements.
Derivative designs
We just did a release of a derivative design. We probably only changed a
handful of cells in the original design. Once our designer checked in his
data, it only took me 1 hour to have a new revision with the new GDS file
and updated configuration. Additionally, since IC Manage clones the
configurations, our data is guaranteed to be the same.
With DITTO, I had to copy over all the libs that need changing, rename
them, and move them to a release area, which took me anywhere from 4 to 8
hours. Plus I could not be certain the data was correct so I had to hand
verify that there were no changes.
Performance
We have 40 users and 2 design sites. We use 2 servers to ensure high
availability and disaster recovery. IC Manage local performance is
virtually instantaneous - our LAN traffic is the only bottleneck.
As for data transfers via our slower WAN, when I tested IC Manage a year ago,
I did a check-out and check-in of a 300 MB Cadence file from our remote
server thousands miles away. It took ~5 minutes on an HP ProLiant with two
quad core processors. I am guessing IC Manage has done some performance
improvements since then. IC Manage got around our WAN bottleneck by having
their proxy server work as a local copy of the data being fetched over the
WAN. The first fetch of data is stored in the proxy, and every subsequent
fetch is local. The proxy server and the main appliance are kept in sync.
Reporting
The IC Manage interface gives us top level information on our library of
files and the history of our design. We can write scripts to report
virtually unlimited data. That is, we have not yet run into any capacity
limits. We have done 5-10 million gates.
Resistance to adoption
We have two main groups using IC Manage GDP. After a year, one of our
groups is fully on board. However, even though IC Manage is well
integrated and the ease of use is straightforward, the second group is
about 70% of the way there. The second group resisted the change in
great part because they simply didn't trust the new system. IC Manage
GDP can only manage libraries it knows about, so some of the designers
would go around the system, and then populate their changes into the
system.
We can't completely enforce something like this technically so we are
relying on managers to drive the change from a top down organizational
directive. The synched release is what makes IC Manage powerful -- but
some designers are reluctant to share their changes right away. We let
them know we will handle the library release that gets linked to the
library release database, so they can make as many changes as they
want.
One thing we learned from our deployment is that it was too hard to
get our designers to use a new DM process in the middle of a project.
So we waited to set up IC Manage GDP until we had new projects.
As the second design team is seeing the benefits from the experience
of the first design team, they have slowly been coming around and we
are continuing to see progress.
Early Problems
I currently don't have any IC Manage GDP improvements or fixes in their
queue, but I can tell you some of our past problems. I've only had a
handful of bugs since we started using it:
1. At one point IC Manage GDP's response time for the "library
refresh" command within the Cadence interface was slow. We
had over 50 libraries and it was taking about ~30 seconds each
to refresh them. It wasn't a show stopper. IC Manage fixed
it within 10 days, so that the same number of libs refreshed
in under 5 seconds each.
2. I had master-slave issues between servers and their AE came
over personally to fix it.
3. We had only one show stopper - we tried to sync a workspace
using a new release of their IC Manage project manager and it
would hang. IC Manage responded quickly and had it fixed
within 2 days. I used an older ICMPM version in the meantime.
IC Manage's support team is very responsive. We send in our request
via email or submit it online and get an auto-reply with ticket number
right away. Roughly 90% of the time a human replies within an hour.
IC Manage is a big step up compared to using our old DITTO/GNATS system.
- [ The Wolverine ]
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