Timetable
ICEP talks will be held in Lecture Theatre 144 in Huxley Building (building 13 on the campus map) on the South Kensington Campus, apart from the EFL/ICEP invited evening lecture, which will be held in room G34 in the Sir Alexander Fleming Building (building 33 on the campus map).
Names in bold are invited talks, the others accompany an accepted extended abstract. Non-invited talks each have a half hour slot — we would expect the talk to last around 20 minutes to leave ample time for questions and transition to the next speaker.
Tuesday 29th May
Morning session | |||
08:30 – 09:20 | Registration and Tea/coffee | Huxley 217/218 | |
09:20 – 09:30 |
Jeremy Bradley
Imperial College London |
Welcome | |
09:30 – 10:00 |
James Snee
University of Cambridge |
Energy performance and accounting in mobile operating systems
Abstract:
One obvious method of accounting for an application or subsystem's energy
usage involves simply subtracting the energy usage of the device when running
the application from idle consumption. For example, recent work has calculated
the incremental energy cost of sending messages of varying size over a Wifi
network by subtracting average idle power from power consumed under the chosen
workload. But evidence shows that these systems aren't as entirely predictable
as one would hope when accounting for energy in this way.
Despite a clear trend the results include a number of prominent outliers.
Given
that this trend supports our expectations for energy consumption it seems
likely that the outliers shown have resulted from non-representative
experimental runs. For example, the preemptive multi-tasking nature of the
underlying Linux OS could mean that the outlier points include energy costs
from other, unrelated, activity. This presents two interesting research
questions. First, where is the energy actually being consumed? And second,
what causes these outliers?
In this paper we describe our initial work on instrumenting the Android
operating system. The goal is to account for energy consumption at the OS
level, and to automatically identify these non-representative runs through
unobtrusive monitoring of the system under test.
| Slides: pdf |
10:00 – 11:00 |
Ranveer Chandra
Microsoft Research |
Smart offload to increase the battery life of mobile devices (part 1)
Abstract:
Mobile devices are severely battery constrained. While smartphone capability
has increased manifold in the last fifteen years, the battery energy density
has only doubled. We have been exploring several techniques to improve the
battery lifetime and in this talk I will discuss one such technique –
offloading. In particular, by offloading computation from the main processor
to either a lower power core, the network interface or to the cloud, we can
put portions of the mobile device to sleep, thereby saving significant amount
of energy.
| Slides: pdf |
11:00 – 11:30 | Tea/coffee | Huxley 217/218 | |
11:30 – 12:00 |
Ranveer Chandra
Microsoft Research |
Smart offload to increase the battery life of mobile devices (part 2) | |
12:00 – 12:30 |
Daniel Kelly
Imperial College London |
Disaggregating multi-state appliances from smart meter data
Abstract:
Smart electricity meters record the aggregate consumption of an entire
building. However, appliance-level information is more useful than aggregate
data for a variety of purposes including energy management and load
forecasting. Disaggregation aims to decompose an aggregate signal into
appliance-by-appliance information. Existing disaggregation systems tend to
perform well for single-state appliances like toasters but
perform less well for multi-state appliances like dish washers and tumble
driers. In this paper, we propose an expressive probabilistic graphical
modelling framework with two main design aims: 1) to represent and
disaggregate multi-state appliances and 2) to use as many features from the
smart meter signal as possible to maximise disaggregation performance.
|
|
12:30 – 13:00 |
Neil Davies
Predictable Network Solutions |
Relating delivered experience to effects of underlying resource sharing
Abstract:
Making choices as to how resources are shared requires an approach that helps
decision makers make good, rational choices. Such approaches need to help
inform likely outcomes given a particular resource allocation strategy as well
as the other way round. This talk outlines the approach that has been used by
us to discuss, plan and deliver more optimal use of another ephemeral
resource, data network capacity, and its relationship with delivered quality
of experience. Key in the approach is the creation of the boundaries that can
be related to the business sectors so that the relevant stakeholders can
understand their role, their added value and hence their likely income
sources. We see that any optimisation of power will have to address similar
issues in order to have a substantive effect.
| Slides: pdf |
13:00 – 14:00 | Lunch | Huxley 217/218 | |
Afternoon session | |||
14:00 – 15:00 |
Isi Mitrani
Newcastle University |
Energy saving and performance in service centers
Abstract:
We consider the problem of managing a service center where it is desirable to
keep power consumption low, while at the same time maintaining high
performance levels. These conflicting objectives are addressed by designating
one or more blocks of servers as `reserves', to be powered up and down when
the demand increases above or falls below certain thresholds. The questions of
how to choose the paremeters of the operating policy are answered by analyzing
suitable queueing models. These may allow customers to defect, i.e. to leave
the system when their waiting times are too large. Simple and easily
implementable heuristics are proposed and numerical results are presented.
| Slides: pdf |
15:00 – 15:30 |
Rossella Macchi
Politecnico di Milano |
An energy-aware methodology for live placement of multi-mode virtual machines in the data center
Abstract:
Desktop virtualization is a promising technology to improve the IT system
management and provide a unified environment to the users. However, the users
profile is usually overestimated in terms of allocated resources to guarantee
the performance in every workload conditions. This usually leads to an
unefficient use of resources and a huge energy consumption of the data center.
This work proposes an approach to reduce the data center energy consumption by
dynamically placing and dynamically adapting the performance profiles of
virtual machines (VMs). We adopt two profiles with different resource
requirements which the user can dynamically select based on the
actual set of running applications. Then, we propose a mathematical approach
and a heuristic approximated solution to efficiently place and migrate the
virtual machines, while reducing the number of the active servers and the live
VMs migrations. The results obtained on a realistic dataset took from a
production environment show that the proposed approach is able to reduce the
energy consumption of the data centers by almost 30% in average by proper
allocating the virtual machines on the available servers.
| Slides: pdf |
15:30 – 16:00 | Tea/coffee | Huxley 217/218 | |
16:00 – 17:00 |
Adam Wierman
Caltech |
Algorithmic challenges for greening data centers
Abstract:
Given the significant energy consumption of data centers, improving their
energy efficiency is an important social problem. However, energy efficiency
is necessary but not sufficient for sustainability, which demands reduced
usage of energy from fossil fuels. In this talk, I will describe some recent
work highlighting the algorithmic challenges associated with "greening" data
centers. I will focus on two applications -- (i) dynamic resizing within a
data center and (ii) geographical load balancing across an Internet-scale
system. In both contexts I will present our new algorithms, which provide
significantly improved performance guarantees when compared with the
"standard" approaches using Receding Horizon Control. Additionally, if time
allows, I will briefly discuss the our recent progress toward the
implementation and evaluation of these algorithms in industry data centers.
| Slides: pdf |
17:00 – 17:30 |
Matthew Forshaw
Newcastle University |
A novel approach to energy efficient content distribution with BitTorrent
Abstract:
The energy efficiency aspects of IT infrastructure and communications systems
are facing increased scrutiny, and a broad range of compelling financial,
social, political and legislative factors is emerging. In this paper, energy
efficiency considerations are addressed in the context of BitTorrent. We
provide mechanisms to facilitate energy efficiency, namely Energy Proportional
Tracker Migration, Peer Connectivity Shaping and Elastic Capacity
Provisioning. We propose an energy-efficient content distribution system
employing these mechanisms to minimise energy consumption and reduce cost.
| Slides: pdf |
18:30 – 20:30 | ICEP Colloquium Reception at 170QG | 170 Queen's Gate (for full delegates and invited speakers) |
Wednesday 30th May
Morning session | ||||
08:30 – 09:00 | Registration and Tea/coffee | Huxley 344 | ||
09:00 – 10:00 |
Erol Gelenbe
Imperial College London |
Dynamic energy management with/for smart ICT
Abstract:
ICT is becoming one of the main culprits of CO2 emissions, already on a par
with air travel, and soon probably doing even more damage. At the same time
ICT is offering cleaner substitutes to emissions in areas such as transport
because of the potential for substituting on-line activities for physical
activities, such as working at home rather than commuting to an office.
Furthermore ICT offers the potential to manage energy more efficiently and for
better matching supply and demand, and substituting renewable energy sources
in the place of fossil fuels. This lecture will address some of these
questions from the perspective of classical computer systems performance
engineering and show how some of our well established methods can be used to
understand the trade-offs and help improve the outcomes.
|
||
10:00 – 11:00 |
Yuan Chen
HP Labs |
Data center performance and power management
(part 1)
Abstract:
Data centers are very expensive to operate due to the power and cooling
requirements of IT equipment. Rising energy costs, regulatory requirements and
social concerns over green house gas emissions amplify the importance of
energy efficiency. However, energy efficiency is for naught if the data center
cannot deliver IT services according to predefined performance goals, as
performance violations result in lost business revenue. Thus, an important
question in data center resource management is how to correctly provision
resource, such that performance requirements are met while minimizing energy
consumption. This talk discusses several approaches in both theory and
practice to improve the overall efficiency of data center operations.
| Slides: pdf | |
11:00 – 11:30 | Tea/coffee | Huxley 344 | ||
11:30 – 12:30 |
Yuan Chen
HP Labs |
Data center performance and power management (part 2) | Slides: pdf | |
12:30 – 13:00 |
Samyukta Sethuraman
Texas A&M University |
Application routing and server speed scaling for energy efficiency in data centers
Abstract:
It is well-documented and accepted that data centers consume a phenomenal
amount of energy. A significant portion of that can be reduced by resource
management strategies such as assigning applications to servers, speed
scaling, powering servers on or off and intelligent routing. Our group's
previous study indicated tremendous gains by applying the above strategies in
a unified and correlated fashion. However, solving a single model considering
all these aspects is computationally intensive and in the current study, we
propose a decomposed framework in which decisions at the lower level are made
based on the decisions at the higher level. In this framework, decisions need
to be made at multiple granularities. We consider a scenario in which a
homogeneous set of servers serve a set of applications which bring demands
according to a time varying load pattern. In the higher level, decisions are
made for a longer time period like a day. At this level, the applications are
assigned to servers according to correlations between the applications'
arrival pattern. The objective is to have either strongly positively or
strongly negatively correlated applications being served by the same server so
that the server can either be turned off completely at some time periods in
the first case, or can operate at a near-constant low speed in the second
case. At the lower level, the decisions are made for a shorter time frame, for
example an hour. The aggregate arrival rates over this time frame are
collected. Routing decisions i.e. what fraction of arrivals of an application
is routed to which server, are made by solving a deterministic optimization
problem to minimize the energy utilized by the servers subject to QoS
constraints. The decisions on server speeds are also made in this stage.
Finally, we provide a fluid flow model to analyze the performance of the
system under the decisions made above. In this analysis the stochastic system
is modeled in real time as a semi-markov process.
| Slides: pdf | |
13:00 – 14:00 | Lunch | Huxley 344 | ||
Afternoon session | ||||
14:00 – 14:30 |
Maryam Elahi
University of Calgary |
Optimization problems in speed scaling systems
Abstract:
Dynamic speed scaling has received significant attention in the recent
literature as an effective method for balancing the need for higher speeds and
the associated cost of energy. In this work, we investigate the tradeoffs
between energy consumption and quality of service measures, such as response
time and fairness in speed scaling systems. We first demonstrate that in a
single server system with coupled speed scaling, where speeds are decided by a
monotonically increasing function in the queue length, no policy can
outperform the Processor Sharing in terms of response time and be fair to all
jobs. We then introduce the notion of decoupled speed scaling, wherein the
speed scaling function is not sensitive to the scheduling decisions, but
adjusts the service rate based on the incoming load. Our initial simulation
results suggest that in a model where there are costs associated with
unfairness, decoupled speed scaling can be advantageous over the coupled speed
scaling systems. Finally, we propose an objective function that combines the
costs associated with different quality of service requirements under the
umbrella of a general cost function. We aim to study the innate interactions
between the scheduler and speed scaler under this model.
| Slides: pdf | |
14:30 – 15:30 |
Evgenia Smirni
College of William and Mary |
Autonomic exploration of trade-offs between power and performance in disk drives
Abstract:
Over-provisioning is a standard capacity planning practice that leads to disk
drives that operate mostly under very low utilization (as low as single digit
utilization) but that are consuming disproportional amounts of power.
Methodologies that place the disk drive into a low power mode during idle
times can assist in conserving power. This is a challenging problem because
the performance of future jobs cannot be compromised, yet there is no
knowledge of future disk arrivals. In this paper we explore the above problem
by exploring ranges and trade-offs of possible power savings and performance
within a set of enterprise storage traces. We demonstrate the difficulty of
obtaining significant power savings even in traces where overall utilization
is less than 5% and explore the feasibility of popular schemes such as
workload shaping for power savings. We also propose an autonomic algorithm
that suggests when and for how long a power savings mode should be activated
given an acceptable performance degradation target that is user provided. The
robustness of the algorithm is illustrated via extensive experimentation.
| Slides: pdf | |
15:30 – 16:00 | Tea/coffee | Huxley 344 | ||
16:00 – 17:00 |
Adam Wierman
Caltech |
Energy procurement in the presence of intermittent sources
Abstract:
The increasing penetration of intermittent, unpredictable renewable energy
sources, such as wind energy, poses significant challenges for the utility
companies trying to incorporate renewable energy into their portfolios. As a
result, there is considerable discussion about how electricity markets should
be restructured in order to facilitate the integration of renewable energy
into the grid. Suggestions include adding additional markets, moving markets,
closer to real-time, etc. In this talk, I will discuss how the optimal energy
procurement of a utility company changes as a result of an increasing
penetration of intermittent renewable resources, and what impact this should
have on electricity market structure.
| Slides: pdf | |
EFL/ICEP evening lecture / reception | ||||
18:00 – 19:00+ |
Francine Bennett
Mastodon C |
Carbon reductions in computing: a pragmatic approach
Abstract:
Cloud computing is a powerful tool which enables massive-scale data analysis
and machine learning, but also has a very large carbon footprint, especially
since many public cloud providers are powered by coal-fired grids (annual data
centre emissions are currently ~75 million tonnes and growing). This talk
discusses some practical approaches to reducing the carbon footprint of
computing in data-led businesses.
Speaker biography: Francine is CEO and co-founder of Mastodon C, a cleantech company focusing on reducing carbon emissions in cloud computing without impact on cost or performance. Formed in February 2012, its goal is to help reduce global carbon emissions by 1%. Previously Francine has worked as Operations Director at Ask.com and Senior Financial Analyst at Google. She graduated from the University of Oxford in 2002 with a first class BA in Maths & Philosophy. More information | Slides: pdf |
Thursday 31st May
Morning session | |||
09:00 – 09:30 | Tea/coffee | Huxley 344 | |
09:30 – 10:00 |
Richard Hayden
Imperial College London |
Mean-field models for interacting battery-powered devices
Abstract:
We show how the mean-field approach can be extended to massively-parallel
systems of interacting Markovian fluid models which can be used to describe
networks consisting of many nodes, each powered and dependent on a local
battery source. The mean-field limits manifest themselves as solutions to
partial functional differential equations which admit inexpensive numerical
solution using standard techniques. Results are compared here with stochastic
simulation and show excellent agreement for reasonable population sizes.
| Slides: pdf |
10:00 – 11:00 |
Miklos Telek
Technical University of Budapest |
Markov fluid models for energy and performance analysis
(part 1)
Abstract:
Markov fluid model is a flexible modeling tool to describe the behavior of
system with hybrid (discrete and continuous) state space. One of the
continuous variable characterizing the system behavior is the energy level.
This way this modeling approach allows a combined analysis of system
performance considering the energy consumption. The talk is going to survey
the background of Markov fluid models and introduces some application
examples.
| Slides: pdf |
11:00 – 11:30 | Tea/coffee | Huxley 344 | |
11:30 – 12:30 |
Miklos Telek
Technical University of Budapest |
Markov fluid models for energy and performance analysis (part 2) | |
12:30 – 13:00 |
Gareth Jones
Imperial College London |
Using fluid queues to model energy storage and distribution
Abstract:
Energy storage and distribution is an increasingly important problem as
renewable (unreliable) energy sources supply more of our power needs. In this
extended abstract we consider a simple network of energy suppliers, consumers
and buffers modelled as fluid queues. Analytical evaluation of networks of
fluid queues is hard as even tandem networks do no have a product form
solution. We improve an approximation algorithm previously introduced to work
in this new setting and evaluate our results using the Java JINQS simulator.
| Slides: pdf |
13:00 – 14:00 | Lunch | Huxley 344 | |
Afternoon session | |||
14:00 – 15:00 |
Evgenia Smirni
College of William and Mary |
How to tame burstiness and save power in multi-tiered systems
Abstract:
Burstiness (i.e. sudden surges) in user demands in enterprise systems that
operate under the multi-tiered paradigm is a common phenomenon that leads to
overprovisioning: the system is configured with excess hardware to meet peak
user demands, often resulting in excessive (and unnecessary) power costs. In
this talk, we present Fastrack, a parameter-free algorithm for dynamic
resource provisioning that uses simple statistics to promptly distill
information about changes in workload burstiness. This information, coupled
with the application's end-to-end response times and system bottleneck
characteristics, guides resource allocation, which proves to be effective
under a broad variety of application burstiness profiles and bottleneck
scenarios. Extensive simulations illustrate Fastrack's robustness for
consistently meeting predefined service level objectives while minimizing
power usage.
| Slides: pdf |
15:00 – 16:00 |
Guillaume Pierre
Vrije Universiteit |
Performance control for complex Web applications
(part 1)
Abstract:
Dynamic resource provisioning aims at maintaining the end-to-end response time
of a web application within a pre-defined range (Service Level Objective, or
SLO). Provisioning resources for applications composed of multiple services
remains a challenge. When the SLO is violated, one must decide which
service(s) should be re-provisioned for optimal effect. We propose to assign
an SLO only to the front-end service. Other services are not given any
particular response time objectives. Services are autonomously responsible for
their own provisioning operations and collaboratively negotiate performance
objectives with each other to decide the provisioning service(s). After
presenting the resource provisioning techniques themselves, I will discuss
their application and implementation in the context of the ConPaaS runtime
environment for elastic Cloud applications.
| Slides: pdf |
16:00 – 16:30 | Tea/coffee | Huxley 344 | |
16:30 – 17:30 |
Guillaume Pierre
Vrije Universiteit |
Performance control for complex Web applications (part 2) | |
19:30 – 21:00 | ICEP Colloquium Dinner at ognisko | 55 Exhibition Road (for full delegates and invited speakers) |
Friday 1st June
Morning session | |||
09:00 – 09:30 | Tea/coffee | Huxley 344 | |
09:30 – 10:00 |
Lucia Gallina
Ca' Foscari University of Venice |
A probabilistic energy-aware model for mobile ad-hoc networks
Abstract:
Connectivity and energy consumption are two key aspects in mobile ad-hoc
networks (MANETs). My research concerns a probabilistic, energy-aware,
broadcast calculus for the analysis of mobile ad-hoc networks. It is based on
a previous non-deterministic model, the EBUM (Energy-aware Broadcast, Unicast
and Multicast Communications) calculus, which captures essential
characteristics of MANETs, including the ability of a MANET node to broadcast
a message to anyother node within its physical transmission range, and to move
in and out of the transmission range of other nodes in the network. When
dealing with MANETs, which use radio-frequencies to communicate, only
broadcast transmissions are allowed, since channels can not be private.
Moreover communications are not always addressed to the whole network, but a
sender may be interested to reach a specific set of receivers (see, e.g.,
routing protocols, where each packet follows some specific path to reach the
destination). This calculus, while considering the broadcast nature of
communications, focuses the attention on the behaviour of the system with
respect to the intended recipients of a message. The probabilistic version of
the model extends the previous one by introducing probabilities modelling the
mobility of nodes, that are not completely casual, but may depend on several
aspects, such as the physical obstacles of the networks, or the nature of the
devices ( e.g. the vehicular networks). Mobility of nodes is modelled by using
Markov chains. The new calculus has been exploited to make performance
analysis of mobile ad hoc networks, with a particular attention to the problem
of energy conservation. The semantics is inspired by Segala's probabilistic
automata driven by schedulers to resolve the nondeterministic choice among the
probability distributions over target states. A probabilistic observational
congruence has been provided, together with a bisimulation-based proof
technique which allows one to verify whether two networks exhibit the same
observable probabilistic behaviour (connectivity). Then an energy-aware
preorder has been defined which can be exploited to compare the energy
consumption of different, but behaviourally equivalent, networks. As an
application, two well-known automatic repeat request (ARQ)-based error control
protocols (stop-and-wait (SW) and go-back-N (GBN)) have been analysed and
compared in terms of energy consumption.
| Slides: pdf |
10:00 – 11:00 |
Danilo Ardagna
Politecnico di Milano |
Energy-aware autonomic resource allocation in multitier virtualized environments
(part 1)
Abstract:
In recent years, the energy consumption associated with Information Technology
(IT) infrastructures has been steadily increasing. The reduction of energy
usage is one of the primary goals of green computing, a new discipline and
practice of using computing resources with a focus on the impact of IT on the
environment. A significant amount of work has been done to achieve power
reduction of hardware devices (e.g., in mobile systems to extend battery
life). Nowadays, low power techniques and energy savings mechanisms are being
introduced also in virtualized cloud data centres environments. In such
systems, software is accessed as a service and computational capacity is
provided on demand to many customers who share a pool of IT resources. Energy
savings can be obtained by dynamically allocating computing resources among
running applications and trading off application performance levels with
energy consumption. As the customers access rates change significantly within
a single business day, energy-aware resource allocation is a challenging
problem and techniques able to control the system at multiple time scales are
needed. In our research we have developed a framework addressing very large
scale cloud data centres resource management. To validate its effectiveness,
the proposed solution is compared to top-performing state-of-the-art
techniques. The evaluation is based on simulation and on real experiments
performed in a prototype environment. Synthetic as well as realistic workloads
and a number of different scenarios of interest has been considered.
| Slides: pdf |
11:00 – 11:30 | Tea/coffee | Huxley 344 | |
11:30 – 12:30 |
Danilo Ardagna
Politecnico di Milano |
Energy-aware autonomic resource allocation in multitier virtualized environments (part 2) | |
12:30 – 13:00 |
Ioannis Dimitriou
Imperial College London |
An unreliable vacation queueing model and its application on the DRX mechanism
for power saving in 3GPP LTE
Abstract:
The paper deals with an unreliable queue with modified vacations, timers,
start-up, release period and its application to DRX mechanism for power saving
mode in 3GPP LTE. The modified vacation scheme consists of two periods, a
short DRX and a long DRX. Short DRX, has maximum number of N short cycles. If
N consecutive short cycles end without arrival, the server enters the long
DRX. We give expressions for the number of requests and its mean in steady
state. Decomposition results are also presented. Energy metrics are obtained
and used to provide useful numerical results.
| Slides: pdf |
13:00 – 13:30 |
Peter Thompson
Predictable Network Solutions |
Creating change in large organisations – an experience report
Abstract:
Increasing overall power "efficiency" is going to mean changed practices - changing
practices means effecting change in organisations, having a large scale effect
will require large organisations to change their practices in relative short
order. Large organisations are not a single cohesive entity, it comes down to
a complex interaction of people, practises, culture (both national and
organisational) and, in no short measure, inertia. In this talk we will give
examples of issues we have encountered when attempting to change perception
and practices within large organisations, such as multi-nationals and
government.
| Slides: pdf |
13:30 – 14:00 | Lunch-to-go | Huxley 344 |