editor's blog
Subscribe Now

The Clouds Converge

We’ve been watching the cloud computing space, and Synopsys has been playing a visible role in exploring the public cloud for compute resource elasticity during simulation. We took a brief look at an attempt they made to demo the cloud at DAC, which was sabotaged by one of their own hard drives.

So yesterday I got a make-up session from Alex Seibulescu, a Synopsys senior staff engineer. It was also useful in that we weren’t under the same time pressure as a quick DAC presentation might have, so, in addition to showing the simulation run, he was able to delve a bit more into the management of the cloud resources.

The demo consisted of a script executing on a Synopsys computer. In fact, one of their security features involves establishing an IP address from which the cloud can be manipulated. This was Synopsys’s external IP address, so any attempts to run the script from some other IP address would be rejected.

The script is, for the most part, just like any other script. It involves secure shell (SSH) and secure copy (SCP) commands as well as Synopsys’s SC2 command.

The SC2 command is the catch-all command that wraps all of the underlying activities required to manage Amazon. It’s very high-level, making all of the Amazon details opaque. There are four options you can use with the SC2 command: create; query; modify; and delete. These provide log results that can be piped into a file; that file can then be searched for information. For instance, when “create” is used to build a new cluster, the resulting log file can be grepped to extract the cluster ID number, which is required for further commands for that cluster.

His script created a cluster, got the regression suite going, and then did some dynamic resource balancing on the fly. The script checked the progress at a time 50% through when the suite needed to be complete. If it was less than 50% (which, of course, it was), then more cores were added.

The concept of a “cluster” is a master node, a license server, and then zero to some large number (hundreds; theoretically, limited only by what Amazon owns) of worker nodes. Each core on a worker node is considered an instance (a CCI); when you reserve cores, you reserve an entire machine (the machines are not “multi-tenanted” so you’re not sharing with anyone else). The machines have 8 cores, so you have to allocate CCIs in multiples of 8.

For the example, he started with 8 CCIs and then added 32 part way through to finish faster. That’s a simplistic approach: because this can all be done programmatically, you could, for example, figure out how far behind schedule you were to figure out the right number of CCIs to add (rather than just adding a fixed 32).

Each computer is a Linux SMP box, with jobs allocated by a load-sharing program. Synopsys provides sg (Sun GridEngine), which is free, or, if you have LSF licenses, you can use LSF as well.

Once the job completed, the script tarred up the results and downloaded them; the cluster was then destroyed. If the cluster were going to be used again soon, it could be left up, with all worker nodes de-allocated. That would allow all of the configuration, design, and results data to remain in the cluster. Once the cluster is destroyed, all vestiges of the session disappear (meaning it’s critical to make sure you’ve downloaded your results before destroying the cluster).

As the job was running, Alex was able to go to a website to check the progress of the run. There was lots of information – in fact, more than really needed by a typical user (which is useful at this stage for any debug needs).

We also discussed versioning. There’s a version of VCS that a user will get by default; if a different version is needed, the customer can work with Synopsys to make that version available. Synopsys also doesn’t upgrade versions on the fly: any upgrades would typically be initiated by the customer, most likely after that customer has upgraded their own installations to a new version. So there’s no chance that a version would change in the middle of a project.

Leave a Reply

featured blogs
Nov 25, 2020
It constantly amazes me how there are always multiple ways of doing things. The problem is that sometimes it'€™s hard to decide which option is best....
Nov 25, 2020
[From the last episode: We looked at what it takes to generate data that can be used to train machine-learning .] We take a break from learning how IoT technology works for one of our occasional posts on how IoT technology is used. In this case, we look at trucking fleet mana...
Nov 25, 2020
It might seem simple, but database units and accuracy directly relate to the artwork generated, and it is possible to misunderstand the artwork format as it relates to the board setup. Thirty years... [[ Click on the title to access the full blog on the Cadence Community sit...
Nov 23, 2020
Readers of the Samtec blog know we are always talking about next-gen speed. Current channels rates are running at 56 Gbps PAM4. However, system designers are starting to look at 112 Gbps PAM4 data rates. Intuition would say that bleeding edge data rates like 112 Gbps PAM4 onl...

featured video

Introduction to the fundamental technologies of power density

Sponsored by Texas Instruments

The need for power density is clear, but what are the critical components that enable higher power density? In this overview video, we will provide a deeper understanding of the fundamental principles of high-power-density designs, and demonstrate how partnering with TI, and our advanced technological capabilities can help improve your efforts to achieve those high-power-density figures.

featured paper

Simplify your isolated current & voltage sensing designs

Sponsored by Texas Instruments

Learn how the latest isolated amplifiers and isolated ADCs can operate with a single supply on the low side, and why this offers substantial benefits over traditional solutions.

Click here to download the whitepaper

Featured Chalk Talk

General Port Protection

Sponsored by Mouser Electronics and Littelfuse

In today’s complex designs, port protection can be a challenge. High-speed data, low-speed data, and power ports need protection from ESD, power faults, and more. In this episode of Chalk Talk, Amelia Dalton chats with Todd Phillips from Littelfuse about port protection for your next system design.

Click here for more information about port protection from Littelfuse.