Information Technology Reference
In-Depth Information
5
Recommendations
The experimental results presented on this paper lead to a comprehensive understand-
ing on the implications of the supporting infrastructure utilized by Desktop Grids in
relation to its intrusiveness. Since intrusiveness plays a key role in promoting or dis-
couraging the donation of idle computing resources to support Desktop Grids, we
propose a set of general recommendations to minimize it based on our research find-
ings. Such recommendations consider that dynamic performance and energy-efficient
technologies, when incorporated on the supporting processor of desktops, directly
affect the intrusiveness generated by Desktop Grids. Therefore, opportunistic strate-
gies aimed to harvest as many idle computing resources as available should be consi-
dered as intrusive. Indeed, new strategies should be considered in order to minimize
the degradation on the performance that end-users are able to perceive while donating
their idle computing resources to Desktop Grids.
The set of recommendations are focused, but not necessarily limited to, Desktop
Grids based on virtualization to be executed on desktops based on processors ranging
from 1
st
, 2
nd
, and 4
th
generations of Intel Core. Since intrusiveness caused by Desktop
Grids affects the performance perceived by an end-user when simultaneously execut-
ing CPU intensive workloads, we propose that new execution policies should be con-
sidered for this particular scenario. Such policies are based on end-user profiles and
can be divided into two types: pessimistic and optimistic.
Firstly, in the context of pessimistic policies, it is stated that the end-user perma-
nently requires the maximum performance the processor is able to deliver. In such a
scenario, any opportunistic activity generated by a Desktop Grid system must be
halted as soon as an end-user starts using the physical machine. In consequence, as
soon as no end-user is using the physical machine, opportunistic activity should con-
tinue its normal execution. Precisely, the opportunistic harvesting of idle computing
resources must exclusively occur when the physical machine is fully available.
Secondly, in terms of optimistic policies, it is supposed that the end-user tolerates a
level of degradation on the performance delivered by the processor. However, such
level must be in a range of acceptance, that is, at least, discontinuous intrusiveness. In
order to implement optimistic policies, continuous monitoring is required in terms of
computing resources usage. Hence, in the absent of CPU intensive workloads ex-
ecuted by end-users, idle computing resources should be dynamically assigned to the
Desktop Grid system. It is important to emphasize that specific implementations of
such policies depend on the supporting processor architectures to be used.
5.1
A Case Study
In order to briefly illustrate a specific implementation of the proposed policies, a basic
case study is developed. Figure 6 depicts relative
intrusiveness percentage measured
over a desktop computer based on the Intel Core i7-4770 architecture. It is important
to note that relative
intrusiveness in considered in terms of the performance an end-
user is expecting from the physical machine and its formula is explained as follows:
