Frank Schirrmeister of Synopsys recently published a blog post called “Busting Virtual Platform Myths – Part 1: “Virtual Platforms are for application software only”. In it, he is refuting a claim by Eve that virtual platforms are for application-level software-development only, basically claiming that they are mostly for driver and OS development and citing some Synopsys-Virtio Innovator examples of such uses. In his view, most appication-software is being developed using host-compiled techniques. I want to add to this refutal by adding that application-software is surely a very important — and large — use case for virtual platforms.
It is a week ago now, and sometimes it is good to let impressions sink in and get processed a bit before writing about an event like the SiCS Multicore Days. Overall, the event was serious fun, and I found the speakers very insightful and the panel discussion and audience questions added even more information.
The article/editoral “Using virtual platforms to improve AdvancedTCA software development practice” is now up at CompactPCI and AdvancedTCA Systems, an online and paper journal for the rack-based market. It is about our experience at Virtutech in using virtual platforms to drive system and software development for “pretty large” target systems, even those based on standard hardware.
And really, there is no such thing as a standard embedded system. Even if you use a standard backplane and buy off-the-shelf boards and cards to put in it, the combination of cards and added mezzanine cards makes each system quite unique. If you could use completely standard PC hardware for your system with no custom additions or special IO units, the thing would in likelihood not actually be an embedded system.
In the July 2008 issue of IEEE Computer, there is short article called “In Praise of Scripting: Real Programming Pragmatism“, by Ronald P. Loui, a professor at Washington University (WUSTL). The article deals with the issue of what is the appropriate first language to teach new CS (Computer Science) students, and considers that a “scripting” langauge like Python or Ruby might be way better than Java (no doubt about that I think).
What can this teach us for the purpose of simulation and the creation of models of computer system hardware for the purpose of simulation? Maybe a fair bit…
I just spent the first week of Summer vacation practising the Swedish national sport of home renovation. It seems that everyone is doing that all the time nowadays – it might be that I have reached the age of family raising where that becomes important, or it might be that it is a general trend that more people spend more time and money renovating their homes. I think it is the second case.
Anyhow, what we set out to do this year was to replace (most of) the twenty-year-old wooden decking on the backside of our small row house with a new one. This was quite an adventure, as we discovered all kinds of interesting designs and problems with the old decking structure. Problems, which do reflect on the realities of computer programming and simulation.
Yesterday, I had the honor of being the opponent at the PhD defense of Simon Kågström at Blekinge Tekniska Högskola (BTH, Blekinge University of Technology in English). His PhD thesis deals mainly with the multiprocessor port of an industrial in-house operating system, and a secondary theme was the design of the Cibyl C-programs-to-JVM translator. All of his papers are very well-written and a joy to read, and the engineering work behind it is very solid.
The most important data in the PhD thesis is really just how much work it is to do an SMP port of an OS kernel. And how hard it is to get performance up to good levels even with several years of work. Really emphasizes the point that hard work and perseverance and just lots of calendar time is what it takes to create a good SMP OS. That’s why Solaris and AIX are still years ahead of Linux in this respect — you just need to hit the snags, fix them, retest, and hit the next snag. It takes time to polish, basically.
So, if you have any interest in multiprocessor operating systems, Simon’s work is well-worth a read. Also check out his blog at http://simonkagstrom.livejournal.com/. And by the way, he did pass.
This is just a repeat post of http://jakob.engbloms.se/archives/75 . I will present at the ESC Silicon Valley, next Thursday, at 08.30 in the morning. On how to use simulation and virtualization to better develop embedded software.
As a side note, a few years ago, I presented on efficient C programming for IAR Systems, guess that would have made Jack Ganssle happy: he complained about the lack of resource-constrained C programming skills in today’s university graduates in a column at Embedded.com recently. Apparently, the major market-driven education companies in the US have also dropped plain C programming from the course rosters… sounds like an opportunity or void to be filled by the embedded companies. Buy a C compiler, get a free efficient programming course.
In the book “Programming Embedded Systems — with C and GNU Development Tools“, authors Michael Barr and Anthony Massa make some statements on simulation that I just have to disagree with on principle. Read on for what. Note that overall this is a good book, I am not claiming that it is not. The Amazon reviews are pretty good, and having a foreword by Jack Ganssle is always a sign of quality. But I just have to correct them on one little fact…
I attended a DATE 2008 open exhibition panel discussion on multicore programming, organized by Gary Smith EDA. The panel was a few people short, and ended up with just Simon Davidmann of Imperas, Grant Martin of Tensilica, and Rudy Lauwereins of IMEC. A user representative from Ericsson was supposed to have been there but he never arrived. Overall, the panel was geared towards data-plane processing-type thinking, and a bit short on internal dissonance.
I am scheduled to talk at the ESC SV 2008 in the technical program. In 2006 and 2007 my topic was Multicore Debugging, but this year I have changed to Using Simulation Tools for Embedded Software Development. The date is April 17, the time 8.30 to 10.00, and the place the San Jose Convention Center.
See you there!
In a column called The Good News and the Bad News in IEEE Computer magazine (November 2007 issue), Prof. Wayne Wolf at Georgia Tech (and a regular columnist on embedded systems for Computer magazine) talks about the impact of multiprocessing systems (multicore, multichip) on embedded systems. In general, his tone is much more optimistic and upbeat than most pundits.
Bill Murray of the “New Media Outlet” SCDsource has published one of the best articles that I have seen on the use of software simulators and virtual prototypes in industry. The examples in the article run from low-level code run on very accurate simulators all the way to very fast virtual systems that are used instead of actual hardware to train NASA operators. The article covers the end-user perspective and is not particularly oriented towards a particular vendor. It offers some nice insights into the expected and unexpected benefits that various companies have obtained from using simulators of various kinds. As well as some glimpses into the underlying technologies they have chosen, developed, and adapted.
Via thinkingparallel.com I just found an interesting article from last Summer, about the actual non-imminence of the end of the computing world as we know it due to multicore. Written by Mark Nelson, the article makes some relevant and mostly correct claims, as long as we keep to the desktop land that he knows best. So here is a look at these claims in the context of embedded systems.
Continue reading “Mark Nelson’s Multicore Non-Panic and Embedded Systems”
The Register has a pretty good report from the Supercomputing (SC) 2007 conference. Quite knowledgeable, and mostly about the thorny issue of programming massively parallel fairly homogeneous machines likes GPUs and floating-point accelerators. Of course, their commentary has to be commented on. Read on for more.
A small tidbit that I found interesting due to the targeted platform. LinuxDevices reports that the VirtualLogix VLX-NI virtualization layer that used to run only on x86 platforms now also run on TI DSPs in the C64+ series. Basically, you put their virtualization layer on the DSP, and you can then on the same core run both a Linux kernel and a DSP/BIOS kernel. Thus supporting traditional DSP development and Linux-style development on the same core.
Game engine development company Valve has a nice presentation up on their website about how they attacked multithreading. It is a nice example of how to solve multicore programming for a particular domain by the classic layered approach.
The TimeSys Embedded Linux Podcast (also called LinuxLink Radio) is a nice listen about embedded computing using Linux. Sometimes they are a bit too open-source centric, though, and ignore very good tools that live in the classic commercial world. One such example is the recent episode 20 on debugging tools, where they totally ignore modern high-powered hardware-based debugging.
In a report from FTF Paris 2007, Info World makes some interesting comments on security and locking-down of mobile devices. Info World Â» Blog Archive Â» â€˜Flat IPâ€™ mobile networks face new security challenges:
The new version of Trango’s embedded “secure virtualizer” for the ARM Cortex-A9 MPCore is an interesting solution in that it directly applies virtualization technology to the issue of migrating solutions (complete software stacks) from single-core to multicore. The details are a bit sketchy in just how this is done, there is some hardware support in recent ARM architectures, but a little bit of adaptation of a guest OS using paravirtual techniques are likely not a blocker. It also touches on security, implemented using ARM’s trustzone technology. All in all, I think this is a typical example of something that we are going to see much more of.
I just read a EETimes report from a panel at the Power.org Developers Conference (actually, it is more accurately called the Power Architecture Developers Conference, of PADC), about programming multicore processors for the embedded market. Note that I was not there in person, so I can only take the few quotes in the article and comment on them. The main conclusions are that:
- C/C++ is going to be the dominant language for embedded for the near future. Nothing really surprising at that.
- C/C++ being dominant means that parallelism in multicore processors, especially shared-memory systems, will be harder to exploit. That is certainly true.
- Tool vendors have no good idea about what to do next.
- You cannot expect to get traction with a new language.
In a sense, blaming the market for not having the good sense to adapt new tools to tackle multicore.
I don’t think things have to be that bleak.
In my work at Virtutech trying to explain Simics and its simulation philosophy, it is often a struggle to get people to accept that what seems like pretty brutal simplifications of the world actually work quite nicely. Recently, I found a nice analogy in a golf game/simulator. The type where you swing a real club and send a real golf ball through the air.
Continue reading “Golf Games and Computer Simulations”
Joel Spolsky is always worth a read, and in his post Strategy Letter VI he has a lot of smart things to say about how to consider programming. His basic message is that if you optimize your code too much to work well and fit in the memory of a current machine, by the time that you are done, you find yourself run over by competitors that just assumed machines would be faster and used the same programming time to implement cooler products.
I just have to take issue with this.