networking – Observations from Uppsala

“Packet Networks are not Socket Science” – Computer and System Architecture Unraveled Event Two

On Wednesday, November 22, we had our second CaSA, Computer and System Architecture Unraveled, meetup. Same place in Kista as the last time, the 25^th floor of the Kista Science Tower building, thanks to the kind sponsorship of Vasakronan and our collaboration with Kista Science City. This time, the theme was networking – but not at the socket level. Per Holmberg presented how his team used “micro sleep” for power management in line-rate network processing, and Hans Brandberg talked about the Precision Time Protocol. Another great event!

Intel Blog Post: Simulation a Thousand Target Machines – in 2004 and 2018

Back in 2004, the startup Virtutech built a crazy demo for the 2004 Embedded Systems Conference (ESC). Back then, ESC was the place to be, and Virtutech was there with a battery of demos to blast the competition. The most interesting demo from a technology perspective was the 1002-machine network, as described in an Intel Developer Zone blog post of mine.

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Intel Blog: Wind River Using Simics to Test IoT at Scale

intel sw small This really happened last week, but I was in the US for the DAC then. I did another blog on Intel Software blog, about a white paper that Wind River put out about how they use Simics internally. The white paper is a really good set of examples of how Simics can be used for software development, test, and debug – regardless of how old or new the hardware is. It also touches my favorite topic of IoT simulation and scaling up – Wind River is actually using Simics for 1000+ node tests of IoT software! Read on at https://blogs.intel.com/evangelists/2016/06/06/wind-river-uses-simics-test-massive-iot-networks/

Wind River Blog: Internet-of-Things Massive Simulation using Simics

There is a new post at my Wind River blog, about how Simics is used to simulate large wireless networks for IoT (Internet-of-Things) applications.

It is funny for me to be back at the IoT game. A decade ago (time flies, doesn’t it?), at Virtutech, I and Johan Runeson took part in an EU research project on exactly this topic. Unfortunately, we had to back out of that project due to economic circumstances and failing management commitment, but we still learnt a few things that were relevant now that we are back in the IoT game. In particular, how to simulate wireless networks in a reasonable way in a transaction-level simulator. Thus, payback for the investment took 10 years to arrive, but it did arrive. To me, that underscores the need to be a bit speculative, take some risk, and try to explore the future.

Wind River Blog and Movie: Demo of Simics Debugging

Last year, I did a Simics webinar which included a two-part demo of how to use Simics to debug an endianness bug in a networked system as it migrates from big-endian to a little-endian system. Along the way, I also showed off various Simics features like reverse execution and checkpointing and scripted execution.

The demo is now online at the Wind River Youtube channel, and the setup is explained in a blog post at the Wind River company blog which is worth reading before watching the video.

Wind River Blog: Teaching Networking with Simics

On the Wind River corporate blog, I have put up a blog post about how Wind River Education Services is going to use Simics to teach networking. What is interesting with this approach is that it shows how a virtual platform can be used for tasks like teaching that don’t have much to do with hardware modeling or similar “typical” VP uses. In this case, the key value is encapsulation of a set of machines running real operating systems and software stacks, and with lots of networks connecting them.

Back to Bare Metal

Once upon a time, all programming was bare metal programming. You coded to the processor core, you took care of memory, and no operating system got in your way. Over time, as computer programmers, users, and designers got more sophisticated and as more clock cycles and memory bytes became available, more and more layers were added between the programmer and the computer. However, I have recently spotted what might seem like a trend away from ever-thicker software stacks, in the interest of performance and, in particular, latency.

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Another Layer of Virtual Indirection

gears-modeling After a long break, this is another blog post in the series of “how to do modeling for virtual platforms”. The previous installments dealt with checkpointing and determinism.

This post is about the use of indirection in a model to increase its flexibility and ease of use, at the cost of a bit more work for the first model to be created.In particular, indirection in the sense of having explicit objects in a simulation to represent things like networks and cables connecting virtual machines.

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When does Hardware Acceleration make Sense in Networking?

Yes, when does hardware acceleration make sense in networking? Hardware acceleration in the common sense of “TCP offload”. This question was answered by a very nicely reasoned “no” in an article by Mike Odell in ACM Queue called “Network Front-End Processors, Yet Again“.

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