This summer, the school asked professors if they would be interested in leading book discussions with incoming first-year students in Computer Science.  I, along with many other professors, volunteered, where each of us could select our specific title to discuss.  I proposed reading, The Martian, by Andy Weir.  What follows is not a review of the book, which I really enjoyed, but rather a summary of the discussion points from the hour we had together. The following text contains many book spoilers. We started the discussion with a short summary of my background and then a stud ..read more

Sol Boucher presented his thesis proposal today via Zoom.  It was well attended and I think many of us are already looking forward to his defense. Lightweight Preemptable Functions (LPF) Function calls require some knowledge of the cost for a program to know whether it can invoke it or not in other time critical execution. In the current space of multitasking, three approaches will be first reviewed: futures, threads, and processes.  Futures rely on the runtime to provide asynchronous execution, but preemption requires yield points, and not all execution can support these poin ..read more

This is a rough writing of the notes from the other two keynotes. Keynote Bill Dally on Domain-Specific Accelerators Moore's Law is over.  Sequential performance is increasing at 3% per year.  And cost per transistor is steady or increasing. Most of power is spent moving data around, so simple ISAs such as RISC are actually inefficient power-wise versus specialized operations.  With special data types and operations, the hardware can be designed so that something taking 10s to 100s of cycles is done in 1.  Memory bandwidth can bottleneck, as "bits are bits". Genome matching, via Smith-Wate ..read more

I am in Columbus Ohio for MICRO 52.  A third of the attendees drove from other "midwestern" universities, of which I am one.  Keynote: Rejuvenating Computer Architecture Research with Open-Source Hardware Moore's Law is irrelevant now, as the cost per transistor has held steady since the 28mm technology node.  The cost of any deployment depends on the development cost and only at very large scales, is the cost per transistor dominant.  Given that, how can we reduce the cost of hardware development. Cambrian explosion of (RISC) ISAs in mid-1980s on with a great diversity of ISAs being create ..read more

Active learning is a set of techniques that require the student to take an active role in their learning during lecture.   Research strongly supports that students will learn more when the lecture utilizes these techniques.  And I have measured this effect in my own courses.  However, this research shows that students like lectures that use these techniques less even though they are learning more.  And I have also informally measured this, such as students who say at the end of the first lecture, "If you are going to require me to participate in lecture, I will not return".  Unfortunately, the ..read more

Naama Ben-David gave her proposal this morning on Theoretical Foundations for Modern Multiprocessor Hardware. Is there a theoretical foundation for why exponential backoff is a good design?  Exponential backoff is a practically developed algorithm that 0. To develop such a foundation, we need to a model of time; however, requests are asynchronous and not according to a single time source.  To address this, model time with adversarial scheduling.  Thus when performing a request, there are three sources of delay: self-delay: backoff, sleep, local computation system-delay: interrupts, context ..read more

This is a summary of the presentation on "The Quest for Energy Proportionality in Mobile & Embedded Systems" by Lin Zhong. We want mobile and other systems to be energy efficient, and particularly use energy in proportion to the intensity of the required operation.  However, processor architectures only have limited regions where these are in proportion, given certain physical and engineering constraints on the design.  ARM's big.LITTLE gives the a greater range in efficiency by placing two similar cores onto the same chip; however, it is constrained by a need to ensure the cores remain c ..read more

Writing parallel code is not considered easy, but it can be a natural approach to some problems for novices.  When a beginner wants something to happen twice concurrently, the reasonable thing would be to do what works once, a second time.  Instead, this may conflict with other constructs of the language, such as main() or having to create threads.  See more here ..read more