Adept Podcast- Interview with Nick Johnson

The Adept project is pleased to present an interview with Nick Johnson from EPCC at the University of Edinburgh. Nick works on different aspects of the Adept project, such as power measurement and the benchmark suite. A paper on benchmarking for power consumption, co-authored by Nick, can be found here. In this podcast Nick discusses the key motivations of the Adept project and its objectives.

Listen:

 

Adept Presentation at EASC 2015

This week Nick Johnson presented work from the Adept project at the EASC 2015 conference in Edinburgh, Scotland. The abstract for the presentation is here:

Energy measurement at the Exascale

Nick Johnson, James Perry and Michele Weiland

When exascale is being discussed, the figures of 1 Exaflop and 20MW are usually cited as the targets to aim for. Runtime performance measurement is well established and a variety of tools available on HPC systems can give a rich variety of accurate information from cache misses to peak flop rate for scientific applications. We find that there is often little consideration given to energy monitoring and when it is present, it is often at low resolution, compared to runtime measurements.

In this paper we examine the energy and power consumption of selected codes which may scale to the Exascale. These are SEISMO, a simple seismic wave propagation modelling code; and Ludwig, a parallel Lattice-Boltzmann code for fluid simulation. The algorithms and data access patterns used in these codes, as well as the strategies used to parallelise them, are representative of a large range of HPC codes, so any results gained from studying them them should have a wider relevance.

Using custom-designed measurement hardware, we instrument a COTS x86 desktop PC with a specification similar to that used in modern HPC nodes. By monitoring the power rails of the CPU, DRAM, disk and network interface (via the PCIe bus), we can build a high-resolution power profile of a scientific code, one much more detailed than we would expect from profiling directly on a HPC node. Extrapolation and inference allows us to predict the component energy and power consumption of the same code running at an exascale node-count. We use a custom measurement system to allow us to perform out-of-band measurements based around a Xilinx Zynq board with appropriate sensors for each power rail. Sampling at 20MHz and with a resolution of 16 bits per measurement (both voltage and current) we can achieve a high quality set of measurements for any rail of interest with no overhead on the system-under-test. Correlation of runtime and power measurements are achieved by post-processing data to gain temporal alignment.

The novelty of our system is that by using our energy-scaling ratio, we can compare the performance of the application in terms of energy to solution and time to solution as the core count scales. The goal then becomes one of minimising both energy to solution and time to solution given the constraints of the target system. We present results for the SEISMO and Ludwig applications gathered from our system using both our own hardware and, for the CPU and DRAM, from hardware counters such as RAPL. This allows to validate results against RAPL which is known to be accurate for Intel CPUs, and to estimate the overhead of using an in-band method like RAPL which can then be added to an energy model for the code.

You can view the slides from the presentation here.

Micro-Architecture Independent Analytical Processor Performance and Power Modeling

Members of the Adept team recently presented a paper 'Micro-Architecture Independent Analytical Processor Performance and Power Modeling' at the ISPASS-2015 conference. You can now view the slides online here.

A paper has also been written and a pre-print copy can be accessed here:

Micro-Architecture Independent Analytical Processor Performance and Power ModelingPerformance and Power Modeling
Sam Van den Steen*, Sander De Pestel*, Moncef Mechri+, Stijn Eyerman*, Trevor Carlson+, David Black-Schaffer+, Erik Hagersten+ and Lieven Eeckhout*

*Department of Electronics and Information Systems, Ghent University, Belgium
+Department of Information Technology, Uppsala University, Sweden

ISPASS 2015 3

Image: Slide 14 from the power point presentation. 

Adept Installs New Hardware

Adept recently deployed its custom power measurement infrastructure on the project's testbed. 

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The Adept measurement system assembled.


This is the Adept measurement system the "correct" way up with the Zynq uppermost for initial testing in the lab at EPCC. The mass of grey cables to the left are the connections to the ADC boards (sensor boards) which are fitted to the power supplies of the machine under test.

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The Adept measurement system installed in its case.


The Adept measurement system is housed in a modified 1U rack-mount PC case. It is connected to a development cluster at EPCC via Gigabit ethernet with an RS232 link available for debugging. The power draw of the system itself can be so low that most PSUs will not start and the disk shown plays no part other than to load down the PSU. The board is mounted the "wrong" way up with the interface board uppermost. The board extending to the left is a standard XRM interface board providing connections for the sensor boards.

Adept at Edinburgh-Tsukuba Workshop

On March 9th and 10th EPCC hosted collaboration workshop between Tsukuba and Edinburgh universities. The meeting brought together researchers from Edinburgh and Tsukuba to present and discuss cutting-edge research in high-performance computing, computer science, and physics being undertaken by both institution. 

A presentation on the Adept project was given at this workshop and the slides can be viewed here:

The Adept project - investigating energy efficiency

Photos of Adept at HiPEAC

At the Adept workshop at HiPEAC 2015 several members of the audience tweeted about the workshop and posted images. Here are some of the images from the workshop that were shared on social media:

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's Stijn Eyerman presents the Adept Tool for performance/power prediction to workshop

 

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's now talking about power measurement techniques at

 

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David Lecomber from talking in front of packed room at w'shop

Adept Workshop at HiPEAC 2015: Energy Efficiency in High-Performance and Embedded Computing

The Adept project is organising a workshop on energy efficiency in high-performance and embedded computing, held in conjunction with HiPEAC 2015, 20th January 2015 in Amsterdam. Please come join us. 

 

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Adept at SC14 in New Orleans!

We will be at SC14 from the 17th to 20th November - come and speak to us about our work at EPCC booth #3445!

In addition to our presence on the exhibiton floor, our Project Coordinator Michèle Weiland will be talking at the 'Extreme-Scale Programming Tools' workshop which runs alongside the conference. Her talk will focus on the importance of tools (such as the Adept performance and power predicition tool) in the advent of the Exascale era.

Adept at European Researchers Night

Members of the Adept Project participated in European Researchers Night, an event to highlight the research being conducted across Europe. Members of the Adept team were on hand at Dynamic Earth, in Edinburgh, to answer questions and demo some of the work being undertaken in HPC. The exhibition was well received and especially popular among members of the public.

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EU Night 1

Images by @SciDidWhat.