Next to that, I also gave a (short) talk on the metrics we devised for quantifying (throughput) performance in a consolidated system. That talk was pretty much the same I gave at HPCVirt earlier this year, so no new slides for that, excepting a few changes. In the meantime, SPEC has published SPECvirt, and they at least seem to be being this a bit better than VMmark, but we still have to wait for more published results to become available before unleashing our wrath on it, should they do things in the wrong way

During this trip, I met a bunch of cool, hospitable people who are busy doing some pretty interesting research. I must confess that I had even worse issues than normal remembering names. Czech clearly is not my forte After the exchange of ideas and thoughts, the trip definitely seemed to have been worthwhile.

The flight to Prague was pretty uneventful, but the return flight was delayed somewhat thanks to the small snow storm that decided to pick its timing in the worst possible manner to pass by and say hello. Our airplane first taxied to one runway, was de-iced there and then had to taxi all the way back to the start of the other runway, as the one we had previously been assigned to for takeoff had been snowed under too much, I think. BTW, Czech Airlines. Free food and a free drink plus coffee or tea. Eat that, Brussels Airlines. After the landing, we were not allowed to taxi up to the gate immediately for undisclosed reasons, but it made me have to run to catch a train. I skipped the purchase of the obligatory Diabolo ticket and filled in the Rail Pass with unauthorised writing gear (a ballpoint pen is obligatory, but I had only a regular pen with me). Luckily — unexpectedly too — the train arrived on time at Brussel-Noord and I could still purchase the Diabolo tax ticket. Thanks to the new schedule — which will prove to be bad in the coming days, I’m sure — I made it to the IC train to Ostend. The NMBS even managed to deliver me on time at my final destination. A rare feat, I agree.

The abstract of the talk reads as follows.

What Can We Learn Using Hardware Performance Monitors on Modern Microprocessors?

Modern microprocessors are ingenious pieces of technology, delivering tremendous amounts of computing power. Because of the complex design of current microprocessors, it is hard to understand how programs behave on them, how they attain the observed performance and what possible bottlenecks need to be dealt with. Usually, exploratory architectural simulation is used prior to implementing a design. However, once the chip has been built, such techniques provide little help to quickly gain insight into the actual behaviour of a program that executes on it: (i) although it can be massively parallelised, simulation remain several order of magnitude slower than execution on real hardware, while the simulated programs grow ever larger (both in memory footprint and in the number of instructions that are executed) during a (typical) run, (ii) getting a simulator to be cycle-accurate is a very complex problem. Moreover, to deliver high performance, a microprocessor contains a lot of components that are not necessary to ensure correct functional behaviour, such as caches, branch prediction, etc.

Benchmarking is one of the fundamental concepts in experimental computer science. Assessing the performance of a microprocessor running a number of benchmarks — or vice versa, understanding the performance of programs — is very important to enhance technology and validate research. For this reason, modern microprocessors are equipped with performance monitoring hardware. These monitors count the events as they occur in the processor during the execution of a program, for example the number of data cache misses, mispredicted branches, etc. This allows a researcher to identity commonly occurring events, and adapt his programs, tool chain, etc. to improve their performance in that aspect.

In this talk we will focus on the design of a modern super-scalar out-of-order processor, and the various components that allow it to operate with high performance. We will explain how the performance monitoring infrastructure can be used for gaining insight in the execution of a program. Because performance counters can leak information about the behaviour of a program, they can also be used as a side-channel to attack implementations of cryptographic algorithms. We will briefly outline an example of such an attack.

I have exported the Keynote presentation into a pdf file (8.9MB). It might not make too much sense without the explanation I would add when presenting, but you might learn a thing or two nonetheless. I hope

The event took place in the Arenberg Castle:

Coffee was served in a hall, where people long dead keep staring at you with jealous eyes that see all the delicious food pass by:

I must confess I understood little of the real cryptographical mojo people were preaching about;-)

The premise of her talk was the fact that there is a lot of information sitting idly around us. This information is not easily accesible. Moreover, relevant information that might help us understand our environment, or help us make decisions is rarely looked up when it is actually required. A typical example of this is shopping. There is much more we could learn, if the information about products was made available in a timely and intuitive fashion. Making this happen in a seamless manner is the goal of Pattie’s current work.

An initial step to making this happen is by equipping users with a wristband containing an RFID-reader. The RFID tag of various products can then be sent to a device capable of interacting with the information world, such as a PDA that can access the web.

This basic piece of equipment can be augmented by a gesture detection system. Such a system allows the users to rapidly browse the information, without requiring him to do awkward stuff of the PDA. A flick of the wrist might mean we want more information. The idea got a little scary when this is applied to people. Touching a person, e.g., by shaking his hand, could give you access to the public (ahem) information on that person. This would be handy when interviewing job candidates. It seems to me that there are much more scary possibilities, that invade our rights or privacy. I can imagine the police force finding this bit of technology quite handy when they have to hunt down people in a crowd. Legitimate use would be chasing criminals, but as we have seen in recent developments, people can be placed on a list of criminals (i.e., the no-fly list) for no other reasons than eating certain types of food.

Anyhow, the obvious step that follows the previous system is providing physical objects with an interface, i.e., creating meta-objects that can be attributed to real-world stuff. These object then provide the information people are interested in for each individual object.

Taking this further, makes us arrive at gaze-based interaction. Here, infra-red detectors determine the point at which somebody looks. A system like this can be used in musea, to broker information about specific details of a piece of art to visitors. Or it can be used to educate users about products.

Minimising the wristband yields a ring that can be used to point at objects. The target can then respond, e.g., by turning a LED green if the product matches your profile, or red if it does not. Said profilecould be a shopping list. Or a list with substances the user reponds allergic to. In this way he can select the goods that do not contain any of these substances without having to scan the list of ingredients over and over. Personally, I think this might be quite handy, although after several times shopping, you do get to know what you can buy and what not.

All of the above imposes technical challenges for both software and hardware:

• what is the user focusing on
• find relevant (personalised) information
• offer this information to the user in an unobtrusive way

I am not sure if this counts as unobtrusive but an example Pattie gave was the following. Objects could gain awareness, and try to attract your attention by lighting up when one passes by. An example is browsing a bookstore, where you can easily see which books match your interest.

A pretty cool example was that of the smart stickies. Current stickes cannot interact with people looking at it. Quickies are post-it notes that can be searched and located and send the writer reminders. For example, a to-do, a tag in a book, meeting data, etc. They can look up people in an address book an notify them automagically. They can also be used to keep track of personal items.

New research focuses on items that have I/O capabilities: I/O objects. An example is a pillow that can act as an interface to send messages to its peer, residing in your home. Another example was given by shutters that will automagically close to keep you out of the sunlight, while allowing light to pass to the rest of the room, so you can read in peace, without all that annoying sunlight getting into your eyes.

The most nifty example of an I/O object were the siftables. These are tiny machines, with their own screen, CPU, etc. that can detect neighbours. They can interact with each other when touching or residing near to each other. For example, if the screens show a face, the image is automatically adjusted such that the face looks at the neighbouring siftable. A possible use would be to teach people the concepts of OO-programming (which seemed to be the only relation the talk had with the main OOPSLA topics), as they have physical objects that can be manipulated and that respond to interaction with other object.

Pattie closed with mentioning the overall goal is to rethink how people can interact with the physical world by delivering just-in-time information in a non-disruptive way. This information would be accessed by different means than what we currently use: a keyboard and a mouse (or substitues for that, such as
a touchscreen).