183 research outputs found
Exploiting Inter- and Intra-Memory Asymmetries for Data Mapping in Hybrid Tiered-Memories
Modern computing systems are embracing hybrid memory comprising of DRAM and
non-volatile memory (NVM) to combine the best properties of both memory
technologies, achieving low latency, high reliability, and high density. A
prominent characteristic of DRAM-NVM hybrid memory is that it has NVM access
latency much higher than DRAM access latency. We call this inter-memory
asymmetry. We observe that parasitic components on a long bitline are a major
source of high latency in both DRAM and NVM, and a significant factor
contributing to high-voltage operations in NVM, which impact their reliability.
We propose an architectural change, where each long bitline in DRAM and NVM is
split into two segments by an isolation transistor. One segment can be accessed
with lower latency and operating voltage than the other. By introducing tiers,
we enable non-uniform accesses within each memory type (which we call
intra-memory asymmetry), leading to performance and reliability trade-offs in
DRAM-NVM hybrid memory. We extend existing NVM-DRAM OS in three ways. First, we
exploit both inter- and intra-memory asymmetries to allocate and migrate memory
pages between the tiers in DRAM and NVM. Second, we improve the OS's page
allocation decisions by predicting the access intensity of a newly-referenced
memory page in a program and placing it to a matching tier during its initial
allocation. This minimizes page migrations during program execution, lowering
the performance overhead. Third, we propose a solution to migrate pages between
the tiers of the same memory without transferring data over the memory channel,
minimizing channel occupancy and improving performance. Our overall approach,
which we call MNEME, to enable and exploit asymmetries in DRAM-NVM hybrid
tiered memory improves both performance and reliability for both single-core
and multi-programmed workloads.Comment: 15 pages, 29 figures, accepted at ACM SIGPLAN International Symposium
on Memory Managemen
Grounds for engagement: Dissonances and overlaps at the intersection of contemporary civilizations analysis and postcolonial sociology
This article elucidates grounds for engagement between two fields of the social sciences engaged in critique of Eurocentrism: contemporary civilizations analysis and postcolonial sociology. Between the two fields there are both evident dissonances and points of potential dialogue and engagement. The article identifies three areas of high contention: divergent perceptions of essentialism, commitments to transformative politics and evaluations of the paradigm of multiple modernities. Despite extensive theoretical and normative differences, a notional intersection of the two fields is outlined in the form of three conceptual and methodological shifts. The first is a displacement of ideal typology. The second move is the most original. ‘Intercivilizational encounters’ and ‘intracivilizational encounters’ are re-cast as ‘intercivilizational engagement’. The goal is the demarcation of a discrete position based on a strong version of interaction that goes further than the notion of intercivilizational encounters recently re-developed in civilizational analysis. To illustrate potential grounds for engagement on this point, the article reviews the historiography of ‘connected histories’ and the insights of relational historians. Finally, the article urges for a nuanced definition of ‘region’ and deeper appreciation of the multiplicity of regionalisms as a meeting point for both fields of critique of Eurocentrism
Different paths to the modern state in Europe: the interaction between domestic political economy and interstate competition
Theoretical work on state formation and capacity has focused mostly on early modern Europe and on the experience of western European states during this period. While a number of European states monopolized domestic tax collection and achieved gains in state capacity during the early modern era, for others revenues stagnated or even declined, and these variations motivated alternative hypotheses for determinants of fiscal and state capacity. In this study we test the basic hypotheses in the existing literature making use of the large date set we have compiled for all of the leading states across the continent. We find strong empirical support for two prevailing threads in the literature, arguing respectively that interstate wars and changes in economic structure towards an urbanized economy had positive fiscal impact. Regarding the main point of contention in the theoretical literature, whether it was representative or authoritarian political regimes that facilitated the gains in fiscal capacity, we do not find conclusive evidence that one performed better than the other. Instead, the empirical evidence we have gathered lends supports to the hypothesis that when under pressure of war, the fiscal performance of representative regimes was better in the more urbanized-commercial economies and the fiscal performance of authoritarian regimes was better in rural-agrarian economie
Diversification of importin-α isoforms in cellular trafficking and disease states.
The human genome encodes seven isoforms of importin α which are grouped into three subfamilies known as α1, α2 and α3. All isoforms share a fundamentally conserved architecture that consists of an N-terminal, autoinhibitory, importin-β-binding (IBB) domain and a C-terminal Arm (Armadillo)-core that associates with nuclear localization signal (NLS) cargoes. Despite striking similarity in amino acid sequence and 3D structure, importin-α isoforms display remarkable substrate specificity in vivo. In the present review, we look at key differences among importin-α isoforms and provide a comprehensive inventory of known viral and cellular cargoes that have been shown to associate preferentially with specific isoforms. We illustrate how the diversification of the adaptor importin α into seven isoforms expands the dynamic range and regulatory control of nucleocytoplasmic transport, offering unexpected opportunities for pharmacological intervention. The emerging view of importin α is that of a key signalling molecule, with isoforms that confer preferential nuclear entry and spatiotemporal specificity on viral and cellular cargoes directly linked to human diseases
Aging-Aware Request Scheduling for Non-Volatile Main Memory
Modern computing systems are embracing non-volatile memory (NVM) to implement
high-capacity and low-cost main memory. Elevated operating voltages of NVM
accelerate the aging of CMOS transistors in the peripheral circuitry of each
memory bank. Aggressive device scaling increases power density and temperature,
which further accelerates aging, challenging the reliable operation of
NVM-based main memory. We propose HEBE, an architectural technique to mitigate
the circuit aging-related problems of NVM-based main memory. HEBE is built on
three contributions. First, we propose a new analytical model that can
dynamically track the aging in the peripheral circuitry of each memory bank
based on the bank's utilization. Second, we develop an intelligent memory
request scheduler that exploits this aging model at run time to de-stress the
peripheral circuitry of a memory bank only when its aging exceeds a critical
threshold. Third, we introduce an isolation transistor to decouple parts of a
peripheral circuit operating at different voltages, allowing the decoupled
logic blocks to undergo long-latency de-stress operations independently and off
the critical path of memory read and write accesses, improving performance. We
evaluate HEBE with workloads from the SPEC CPU2017 Benchmark suite. Our results
show that HEBE significantly improves both performance and lifetime of
NVM-based main memory.Comment: To appear in ASP-DAC 202
Different Paths to the Modern State in Europe: The Interaction between Domestic Political Economy and Interstate Competition
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