Intel Blog: How 3dfx was Built on a Simulator

In the early 1990s, “PC graphics” was almost an oxymoron. If you wanted to do real graphics, you bought a “real machine”, most likely a Silicon Graphics workstation. At the PC price-point, fast hardware-accelerated 3D graphics wasn’t doable… until it suddenly was, thanks to Moore’s law. 3dfx was the first company to create fast 3D graphics for PC gamers.  To get off the ground and get funded, 3dfx had to prove that their ideas were workable – and that proof came in the shape of a simulator.  They used the simulator to demo their ideas, try out different design points, develop software pre-silicon, and validate the silicon once it arrived.  Read the full story on my Intel blog, “How Simulation Started a Billion-Dollar Company”, found at the Intel Developer Zone blogs.

gem5 Full Speed Ahead (FSA)

I had many interesting conversations at the HiPEAC 2017 conference in Stockholm back in January 2017. One topic that came up several times was the GEM5 research simulator, and some cool tricks implemented in it in order to speed up the execution of computer architecture experiments. Later, I located some research papers explaining the “full speed ahead” technology in more detail. The mix of fast simulation using virtualization and clever tricks with cache warming is worth a blog post.

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Intel Blog: Continuous Delivery for Embedded Systems and how Simulation can Help

Doing continuous integration and continuous delivery for embedded systems is not necessarily all that easy. You need to get tools in place to support automatic testing, and free yourself from unneeded hardware dependencies. Based on an inspiring talk by Mike Long from Norway, I have a piece on how simulation helps with embedded CI and CD on my Software Evangelist blog on the Intel Developer Zone.

Off-Topic: Nerja, Costa del Sol, Spain

I and my wife recently took a short vacation in Nerja in Spain, a tourist town on the Costa del Sol. Late February was definitely low season, which made for a rather relaxing experience without the huge crowds that would be expected to fill up the place later in the year.

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”Figure out What to Do”, Says the Manual

I just spend some hours building a new living room PC for the home. I based on common components like a Fractal Design Node 202 chassis and an MSI Z270i motherboard for my Intel Core i7-7700 processor.  Trying to figure out how to put it together was a bit interesting though – especially if I had tried to do so without the help of the Internet.  The manuals that came with some of the components were just completely useless, essentially boiling down to “please figure out what to do”.

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Intel Blog: The Right Mindset and Toolset for Testing

I have a two-part series (one, two) on testing posted on my Software Evangelist blog on the Intel Developer Zone.  This is a long piece where I get back to the interesting question of how you test things and the fact that testing is not just the same as development.  I call the posts Mindset and Toolset

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Intel Blog: Testing and the ESA Schiaparelli Lander

It is really sad that the European Space Agency (ESA) lost their Schiaparelli lander last year, as we will miss out on a lot of Mars science. From a software engineering and testing perspective, the story of why the landing failed  rather instructive, though. It gets down to how software can be written and tested to deal with unexpected inputs in unexpected circumstances. I wrote a piece about this on my blog at the Intel Developer Zone.

Simulics – A New Commercial Reverse Debugger

simulics_logo_just_logoA new entry just showed up in the world of reverse debuggingSimulics, from German company Simulics. It does seem like the company and the tool are called the same. Simulics is a rather rare breed, the full-system-simulation-based reverse debugger. We have actually only seen a few these in history, with Simics being the primary example. Most reverse debuggers apply to user-level code and use various forms of OS call intercepts to create a reproducible run. Since the Simulics company clearly comes from the deeply embedded systems field, it makes sense to take the full-system approach since that makes it possible to debug code such as interrupt handlers.

I have also updated my history of commercial reverse debuggers to include Simulics.

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Intel Blog: Using CoFluent to Model and Simulate Big Data Systems

Cofluent studio Intel CoFluent Technology is a simulation and modeling tool that can be used for a wide variety of different systems and different levels of scale – from the micro-architecture of a hardware accelerator, all the way up to clustered networked big data systems. On the Intel Evangelist blog on the Intel Developer Zone, I have a write-up on how CoFluent is being used to do model just that: Big Data systems. I found the topic rather fascinating, how you can actually make good predictions for systems at that scale – without delving into details. At some point, I guess systems become big enough that you can start to make accurate predictions thanks to how things kind of smooth out when they become large enough.

SiCS Multicore Day 2016 – In Review

sics-logo The SiCS Multicore Day took place last week, for the tenth year in a row!  It is still a very good event to learn about multicore and computer architecture, and meet with a broad selection of industry and academic people interested in multicore in various ways.  While multicore is not bright shiny new thing it once was, it is still an exciting area of research – even if much of the innovation is moving away from the traditional field of making a bunch of processor cores work together, towards system-level optimizations.  For the past few years, SiCS has had to good taste to publish all the lectures online, so you can go to their Youtube playlist and see all the talks for free, right now!

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Intel Blog: Why Target Variation Matters (finding a Xen bug)

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Simics and other simulation solutions are a great way to add more variation to your software testing. I have just documented a nice case of this on my blog at the Intel Developer Zone (IDZ), where the Simics team found a bug in how Xen deals with MPX instructions when using VT-x.  Thanks to running on Simics, where scenarios not available in current hardware are easy to set up.

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UndoDB Recording during Automatic Testing

undo-logoUndoDB is an old player in the reverse debugging market, and have kept at it for ten years.  Last year, they released the Live Recorder record-replay function.  Most recently, they have showed an integration between the  recorder function and Jenkins, where the idea is that you record failing runs in your CI system and replay them on the developer’s machine.  Demo video is found on Youtube, see https://www.youtube.com/watch?v=ap8552P5vss.

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Reverse Debug with Hardware in the Loop

reverse iconLast year (2015), a paper called “Don’t Panic: Reverse Debugging of Kernel Drivers” was presented at the ESEC/FSE (European Software Engineering Conference and the ACM SIGSOFT Symposium on the Foundations of Software Engineering) conference. The paper was written by Pavel Dovgalyuk, Denis Dmitriev, and Vladimir Makarov from the Russian Academy of Sciences. It describes a rather interesting approach to Linux kernel device driver debug, using a deterministic variant of Qemu along with record/replay of hardware interactions.  I think this is the first published instance of using reverse debugging in a simulator together with real hardware.

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Kindle App on Android: Turning off Annoying Page Curl

kindle-app-curlA recent update to the Amazon Kindle app on my Android devices introduced a severely annoying page curl animation when flipping through pages in a book. This unnecessary animation slows things down and disrupts the reading flow, or at least that is my opinion. It was really hard to find any kind of help on the Amazon pages or elsewhere on the Internet for how to turn it off. I finally figured it out, and here is how I did it so that other people with the same problem can search and find a solution…

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Presenting about Simics and SystemC at DVCon Europe 2016

I am going to present a paper about our new SystemC Library in Simics, at the DVCon Europe conference taking place in München next month. The paper is titled “Integrating Different Types of Models into a Complete Virtual System – The Simics SystemC* Library”, and I authored it together with my Intel colleagues Andreas Hedström, Xiuliang Wang, and Håkan Zeffer.

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Intel Blog: Using Simulation Before Code to Architect IoT Software

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On my Intel Software Evangelist blog, I just published an updated version of an interview I first published back in May, about how to use Intel CoFluent Studio for IoT system architecture. This is a really cool story, about how you can use a calibrated simulation model to architect and analyze software performance before actually writing the code! I

Intel Blog: Simulating Six Terabytes of RAM

intel sw smallMy first blog post as a software evangelist at Intel was published last week. In it, I tell the story of how our development teams used Simics to test the software behavior (UEFI, in particular) when a server is configured with several terabytes of RAM. Without having said server in physical form – just as a simulation. And running that simulation on a small host with just 256 GB of RAM. I.e., the host RAM is just a small fraction of the target. That’s the kind of things that you can do with Simics – the framework has a lot of smarts in it.

It was rather interesting to realize that just the OS page tables for this kind of system occupies gigabytes of RAM… but that just underscores just how gigantic six terabytes of memory really is.

Does Documentation Matter for a Product?

How important is the documentation (manual, user guide, instruction booklet) for the actual quality and perceived quality of a product? Does it materially affect the user?  I was recently confronted by this question is a very direct way.  It turned out that the manual for our new car was not quite what you would expect…

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This is just the first page, and as you can see if you know Swedish or German or both, it is a strange interleaving of sentences in the two languages.

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Corsair K65 and K70 Keyboards

When my old CM Storm mechanical gaming keyboard stopped working a while ago, I looked around for replacement alternatives. I ended up getting the new Corsair K65 RGB LUX narrow keyboard. A while earlier this year, I got a Corsair K70 at work. Thus, I can do a double review on a pair of closely related keyboards, but with different key switches, sizes, and backlighting systems.

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Off-Topic: Outlook Plugins do not activate when program starts – registry fix

skypemeetingIn my sporadic series of IT fixes that I happen to find, here is another one about how to fix the load behavior of plugins in Outlook.

This is a solution to a problem that I have had myself with plugins for Outlook. I assume it works the same for other office programs. Basically, some plugins, in particular the Skype Meeting/Lync Meeting plugin, would not load when Outlook started and I was forced to manually enable it in the add-ons manager each time. Highly annoying. I managed to fix it by doing a small registry fix.

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Off-Topic: Cruising Holiday

The family and I spent last week on a cruise in the Mediterranean with Royal Caribbean Cruises (RCC). It was a wonderful vacation, and very family friendly. We did a number of shore excursions and got to see historical landmarks like the stadium at Olympia where the original Olympic games were held. Lounging by the pool on the ship was nice on our sea days, if a bit crowded. Service was fantastic, and you really do not need to think much at all about practical things while onboard. It just happens. Very relaxing. If I compare it to a typical all-inclusive hotel vacation, it is definitely higher quality with the added benefit of moving around and seeing multiple places in a week.

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Prototypical – Good [Book | PR | Reading]

Prototypical cover frontI was at the DAC 2016 conference and exhibition in Austin, Texas, a few weeks ago. On the show floor, going by the S2C booth, I was roped in and got a paper copy of the book Prototypical. The copy was even signed by the authors Daniel Nenni and Don Dingee! Nice touch! The book is more than just marketing material – it provides a good overview of the origins and history of FPGA prototyping, and I found it nice and enjoyable to get more insights into this fairly important part of the EDA tools ecosystem.

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Clocks or Cores? Choose One

Once upon a time, when multicore processors were novelties, multicore was motivated by the simple fact that it was impossible to keep raising the clock frequency of processors. More “clocks” simply would result in an overheated mess. Instead, by adding more cores, much more performance could be obtained without having to go to extreme frequencies and power budgets. The first multicore processors pretty much kept clock frequencies of the single-core processors preceding them, and that has remained the mainstream fact until today. Desktop and laptop processors tend to stay at 4 cores or less. But when you go beyond 4 cores, clock frequencies tend to start to go down in order to keep power consumption per package under control. A nice example of this can be found in Intel’s Xeon lineup.
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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/

A Replay Debugger from 1995!

2016-06-05_21-29-16A comment on my old blog post about the history of reverse execution gave me a pointer to a fairly early example of replay debugging. The comment pointed at a 2002 blog post which in turn pointed at a 1999 LWN.net text which almost in passing describes a seemingly working record-replay debugger from 1995. The author was a Michael Elizabeth Chastain, of whom I have not managed to find any later traces.

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Intel Blog: Finding a Linux Kernel bug by running Simics on Simics

intel sw smallI love bug and debug stories in general. Bugs are a fun and interesting part of software engineering, programming, and systems development. Stories that involve running Simics on Simics to find bugs are a particular category that is fascinating, as it shows how to apply serious software technology to solve problems related to said serious software technology.  On the Intel Software and Services blog, I just posted a story about just that: debugging a Linux kernel bug provoked by Simics, by running Simics on a small network of machines inside of Simics. See https://blogs.intel.com/evangelists/2016/05/30/finding-kernel-1-2-3-bug-running-wind-river-simics-simics/ for the full story.

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First post on the Intel Software and Services Blog

intel sw small I have posted my first blog post to the Intel Software and Services blog channel. The Intel Software and Services blog is one channel in the Intel corporate blog you find at https://blogs.intel.com/.  Other bloggers on the Software and Services channel write about security, UEFI, cloud, graphics, open source software, and other topics. Intel has a large software development community, and we produce quite a bit of software – and we do write about the innovations that come out of Intel that rely on software.

On my part, I will be posting more materials on simulation at Intel, as part of my role as a simulation evangelist on the Software and Service blog channel.

 

David Kanter on Benchmarking and Simulation (Tech Report podcast)

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The Tech Report podcast did an interview with David Kanter earlier this year. David Kanter is an industry veteran who runs http://www.realworldtech.com/, as well as being a regular contributor to the Microprocessor Report. I have read the MPR since my PhD days, and it is still one of the best places for information on new chips. The subject of the podcast episode was an analysis of the somewhat mysterious Softmachines “VISC” processor architecture. However, it rather turned into a very good discussion on how you do performance predictions, performance projections of competing systems, and the nature of benchmarking and benchmark numbers.

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Wind River Guest Blog: Interview with Sangeeta, a CoFluent user doing Software Modeling

Cofluent studioEven though I am now working for Intel, the nice folks at Wind River have let me do blogging on the Wind River blog as a guest anyway.  I first blogged about the fantastic world of simulators that I have found inside Intel, and now a longer technical piece has appeared on a use of Intel CoFluent Studio. I interviewed Sangeeta Ghangam at Intel, who used CoFluent Studio to model the behavior of a complex software load on a gateway, connected to a set of sensor nodes. It is rather different from the very concrete software execution I work on with Simics. Being able to model and estimate the performance and cost and size of systems before you go to the concrete implementation is an important part of software and systems architecture, and CoFluent offers a neat tool for that.

Read the full story on the Wind River blog!

“Architectural Simulators Considered Harmful” – I would tend to agree

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IEEE Micro published an article called “Architectural Simulators Considered Harmful”, by Nowatski et al, in the November-December 2015 issue. It is a harsh critique of how computer architecture research is performed today, and its uninformed overreliance on architectural simulators. I have to say I mostly agree with what they say. The article follows in a good tradition of articles from the University of Wisconsin-Madison of critiquing how computer architecture research is performed, and I definitely applaud this type of critique.

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