Observations from Uppsala – Computer simulation, programming, software, technology, research, and more (since 2007)

Hi Local AI, Draw Me …

I recently built a new desktop computer, featuring an Intel ARC 770 graphics card (just to be different). The card is supported by the Intel AI Playground, which is a software package that makes it dead easy to run AI/large language models (LLM) locally on my GPU. I was curious as to just what this could do, as compared to the big AI models that run on cloud servers.

Reversing out of Reverse

The Intel Simics simulator version 7 removed a long-standing feature from the simulator framework. Reverse execution is no longer available. In its place, in-memory snapshots were introduced, which arguably offer most of the benefits at a lower implementation cost. What happened? I’ve been asked about the reasoning behind the chance on several occasions since I left Intel. I’d like to share my perspective on the decision, as it highlights the challenges of turning an idea into a robust, shippable feature.

“Processor Performance Insights and Optimization” – Computer and System Architecture Unraveled Event Four

Finally, the fourth CaSA, Computer and System Architecture Unraveled, meetup happened on November 6. It took far too long to get it organized, but we finally did it. The theme was about processor performance analysis and efficient processor implementation, offering two talks from very different perspectives. The location was almost the same as before, on the 19^th floor of the Kista Science Tower building. Once more thanks to the sponsorship from Vasakronan and Kista Science City.

DVCon Europe Report on Semiwiki

I posted my first post on Semiwiki! It is a short summary of what we learned at DVCon Europe 2024. Semiwiki is a blog and wiki for the “semiconductor” industry – i.e., it covers topics like EDA tools, semiconductor manufacturing and fabs, hardware design, software design, testing, validation, etc.

Vilnius – History, Russia, Ukraine

We spent a few days in Vilnius at the end of October. Rather late in the tourist season, but the city was still open for business. It was a very good experience. Vilnius is one of the friendliest and cleanest places I have visited. Definitely on the “recommended” list. Here are some assorted notes from what we saw.

More Ghostwrite Bugginess with RISCVuzz

In my previous blog about the Ghostwrite vulnerability in the Alibaba T-Head C910 RISC-V-based processor, I noted that the authors of the paper had found more than just that one bug. The additional bugs are worth their own write-up, as they offer some more examples of what looks to be poor testing.

DVCon Europe 2024 – AI and More

The 2024 DVCon (Design and Verification) Europe conference took place on October 15 and 16, in its traditional location at the Holiday Inn Munich City Centre. This year there was even more talk of artificial intelligence than last year, and quite a few sessions related to virtual platforms. And lots of other interesting presentations and discussions.

Ghostwrite – Now This is Weird

In August, a strange security vulnerability dubbed “Ghostwrite” was making the rounds in the press. Basically, a vector store instruction on an Alibaba T-Head C910 RISC-V-based processor would just write to a physical address without doing a virtual-to-physical translation or checking any kind of access rights. That is just totally weird. Just how could that be implemented and slip through testing???

The Quarterly Product and Feature Update

I think of myself to be a technical person. I like computers, simulators, code, things like that. And obviously interacting with people and helping them solve their technical problems using technology I know. However, it seems that one of the most impactful contributions made during my time at Intel was to start a meeting series. Maybe you can call it a process innovation.

Time to Do Something New

The time has come to do something new. I am leaving Intel (and the Intel Simics team) at the end of September (2024). After more than twenty years with the team and the product this is a big step into the unknown. But when Intel offered a “retirement” package as part of its current round of cost reduction measures, I felt that it was a golden opportunity to find something new to do.

The Event at the End of Universe

This is a short story from the world of virtual platforms. It is about how hard – or easy – it is to model a simple and well-defined hardware behavior that turns out to mercilessly expose the limitations of simulation kernels.

Intel Blog: Parallelizing a Virtual Platform Model

There are many ways to use threading and parallelization to improve the performance of virtual platforms. It is not always easy to successfully use parallelization – it very much depends on the nature of the workloads and model setup – but when it works it can really help. I recently published a long blog post at Intel, detailing an idealized example of threading for a device model that is shipping in the Simics training package.

Just Get the Right Tool!

We recently repaired a fence in our back yard. Not very exciting, but it provides a good case study in how to think about getting the right tools for the job. Or not getting the right tools. And the trade-offs inherent in improving the tools vs just getting a job done with what you have at hand. Which is something all software developers should have sympathy with.

Delivering AI-Based Solutions is not Always Easy

One of the nice properties of delivering software that users install on their own machines is that once the software has been built and shipped, the cost of running it is handed over to the user. The cost per installation and per user is minimal in terms of compute load on the developing company. Of course there are costs for things like support, but that is different. However, having the customer provide the compute resources is not necessarily that easy when it comes to AI-based setups.

Useful Instruction Set Computing

I tend to get into discussions about computer processor instruction-set architecture (ISA) design. ISA design is far from my day job, but it is an interesting topic where everyone working with computers at the machine level have opinions. Typically based on a mix of personal experience and fond memories of particular machines. This in turn leads to intricate and intriguing arguments. In this blog, I will talk about my take on the current state of instruction sets in industry and the age-old “complexity of instruction set” question.