Davit Mirzoyan Successfully Defends PhD Thesis!

On this day, Davit Mirzoyan confidently defended his PhD thesis, earning the right to call himself a doctor. The thesis is entitled Better than Worst-Case Design for Streaming Applications under Process Variation and discusses how process variation during chip manufacturing can be exploited during application mapping and voltage-frequency island partitioning to increase the number of chips that satisfy the real-time requirements of the application. The work is very interesting, as it captures how variation in transistor parameters affect application performance, thus tying together the lowest and the highest levels of system design.

An interesting fact is that due to circumstances beyond Davits control, he had to write his thesis and send it off to the committee in only two months, something most people would not be able to do, yet he delivered a nice piece of work that was referred to as a ‘very smooth read’ by the committee. As Davits co-promotor, I am very proud of his achievement and I have very much enjoyed working with him during the past four years. I wish him the best of luck in his future career.

DRAMPower v3.1 Released!

The latest version of the tool now includes IO and Termination power measures from Micron’s DRAM Power Calculator for all supported DRAM generations. This feature enables support for power estimation of dual-rank DRAMs (DDR2/3/4). Additionally, new warning messages have been added, to identify if the memory or bank state is inconsistent in the user-defined command traces. This release also fixes minor bugs related to Precharge All (PREA) to improve the accuracy of DRAM power estimation.

Check it out here.

Two Papers Accepted at DATE 2014

Today we celebrate that the Memory Team had both papers submitted to DATE accepted as full papers at the conference. The first paper was written by Manil Dev Gomony and is entitled “Coupling TDM NoC and DRAM Controller for Cost and Performance Optimization of Real-Time Systems”. This paper discusses area, power and performance benefits of coupling the arbitration in a TDM NoC with the memory controller arbitration, thereby reducing the number of arbitration points on the path from processor to memory. The second paper entitled “Exploiting Expendable Process-Margins in DRAMs for Run-Time Performance Optimization” was first-authored by Karthik Chandrasekar. This paper shows how to exploit excessive process margins in DRAMs by proposing a methodology for how to determine the minimum timings that a memory can safely run at, thereby improving performance.

Three Presentations at ESWEEK

The Embedded Systems Week kicks off next week in Montreal, Canada. Two of my students will be giving a total of three presentations, which may be interesting for those following my work. First, Sven Goossens will be presenting his CODES+ISSS paper “A Reconfigurable Real-Time SDRAM Controller for Mixed Time-Criticality Systems” on Monday September 30 10:30 – 11:00. On Thursday October 3, approximately, 09:50 – 10:10, he will also summarize all of his work on memory controllers for mixed time-criticality systems in an invited presentation entitled “A Mixed Time-Criticality SDRAM Controller” at the Memory Architecture and Organization Workshop (MeAOW). At almost the same time, October 3 10:00 – 10:30, Davit Mirzoyan will present his paper “Throughput Analysis and Voltage-Frequency Island Partitioning for Streaming Applications under Process Variation” at the Symposium on Embedded Systems for Real-Time Multimedia (ESTIMedia). We hope to see you there!

DRAMPower v3.0 Released!

DRAMPower v3.0 has been released! The tool can now be employed with two interfaces: (1) Command traces and (2) Transaction traces (new feature). To facilitate usage of memory transaction traces, DRAMPower now includes an optional DRAM command scheduler, which dynamically schedules and logs DRAM commands, corresponding to the incoming memory transactions, as if it was connected to a memory controller. The scheduler assumes a closed-page policy, employs FCFS scheduling across transactions and uses ASAP scheduling for DRAM commands. This release also adds support for DDR4 and LPDDR3 devices and fixes minor bugs to improve the accuracy of DRAM power estimation. Click here to check it out.

New position at Czech Technical University in Prague

Today I start a new position as a Postdoctoral Researcher in the Department of Control Engineering at the Faculty of Electrical Engineering at the Czech Technical University in Prague. More specifically, I am in the Industrial Informatics group, led by Prof. Zdenek Hanzalek. Although a new country and a new workplace implies quite a change for me, little will change for those that I collaborate with. I will still do research on real-time systems and I will continue to supervise my students in Eindhoven and Porto. However, my research direction will change slightly within the scope of real-time systems to align with the interests of my new group and to make the most of my stay here.

Accepted Paper at ESTIMedia 2013

To our great delight, Davit Mirzoyan’s paper “Throughput Analysis and Voltage-Frequency Island Partitioning for Streaming Applications under Process Variation” has been accepted at ESTIMedia 2013. The paper extends his earlier work and presents a framework to estimate the probability distribution of application throughput (e.g. frames per second in video decoding) in a system with Voltage-Frequency Island (VFI) partitions in the presence of process variation. The novelty of the framework lies in the computation of the probability distribution of throughput, based on a user-specified set of clock-frequency levels per VFI domain considering both within-die and die-to-die variations of cores. A methodology is furthermore provided to perform variation-aware partitioning of the cores of a MPSoC into VFIs for maximized timing yield (percentage of chips that satisfy a given throughput requirement).

Paper About CompSOC Tool-flow at FPGAworld 2013

A paper about the CompSOC tool-flow has been accepted that describes the highly automated effort of specifying and creating instances of the CompSOC platform, map applications to resources considering their real-time requirements, and executing the resulting system on FPGA. Three sub-flows of the tool-flow and their interactions are briefly explained: 1) the hardware tool flow, capable of translating a high-level description of a CompSOC platform instance into a fully synthesized implementation, 2) A system software flow, generating a software stack including a composable micro kernel, resource managers, drivers, and a virtual platform boot loader, and 3) An application flow that automatically generates a virtual platform configuration for applications that use the Cyclo-static Data Flow (CSDF) model of computation. The paper will be presented at FPGAworld and puts particular emphasis on practical aspects related to the first of these sub-flows and on the interaction with tools for our FPGA target.

Accepted Paper at CODES/ISSS 2013

Our paper “A Reconfigurable Real-Time SDRAM Controller for Mixed Time-Criticality Systems” has been accepted at CODES/ISSS 2013. The paper is first-authored by Sven Goossens and builds on the work of Jasper Kuijsten, a graduated master student from the Memory Team. In this paper, we present a new architecture of our real-time memory controller that supports predictable and composable run-time reconfiguration on use-case transitions, which allows trade-offs between guaranteed bandwidth, response time and power. It also presents a methodology for offering composable service to memory clients by means of composable memory patterns, an extension to our existing pattern-based approach. Lastly, a reconfigurable Time-Division Multiplexing (TDM) arbiter and an associated reconfiguration protocol are proposed. The TDM slot allocations can be changed at run time, while the predictable and composable performance guarantees offered to active memory clients are unaffected by the reconfiguration. The SDRAM controller has been implemented as a TLM-level SystemC model, and in synthesizable VHDL for use on an FPGA platform.

Invited Presentations in Northern, Southern, and Central Europe

The next two weeks involves quite a marketing effort, as I will give three invited presentations about real-time memory controllers in northern, southern, and central Europe, respectively. Tomorrow, I will present our work at the Faculty of Information Technology at Czech Technical University in Prague. On Friday, I will meet with Karl-Erik Arzen and Enrico Bini at the Department of Control at Lund’s Institute of Technology and share my story. Lastly, next week Wednesday, I present at the ReTiS Lab at Scuola Superiore Sant’Anna. I thank all these institutes for the opportunity to present and I hope they will enjoy the story.