ILP and TLP in Shared Memory Applications: A Limit Study

The work in this dissertation explores the limits of Chip-multiprocessors (CMPs) with respect to shared-memory, multi-threaded benchmarks, which will help aid in identifying microarchitectural bottlenecks. This, in turn, will lead to more efficient CMP design. In the first part we introduce DotSim, a trace-driven toolkit designed to explore the limits of instruction and thread-level scaling and identify microarchitectural bottlenecks in multi-threaded applications. DotSim constructs an instruction-level Data Flow Graph (DFG) from each thread in multi-threaded applications, adjusting for inter-thread dependencies. The DFGs dynamically change depending on the microarchitectural constraints applied. Exploiting these DFGs allows for the easy extraction of the performance upper bound. We perform a case study on modeling the upper-bound performance limits of a processor microarchitecture modeled off a AMD Opteron. In the second part, we conduct a limit study simultaneously analyzing the two dominant forms of parallelism exploited by modern computer architectures: Instruction Level Parallelism (ILP) and Thread Level Parallelism (TLP). This study gives insight into the upper bounds of performance that future architectures can achieve. Furthermore, it identifies the bottlenecks of emerging workloads. To the best of our knowledge, our work is the first study that combines the two forms of parallelism into one study with modern applications. We evaluate the PARSEC multithreaded benchmark suite using DotSim. We make several contributions describing the high-level behavior of next-generation applications. For example, we show that these applications contain up to a factor of 929X more ILP than what is currently being extracted from real machines. We then show the effects of breaking the application into increasing numbers of threads (exploiting TLP), instruction window size, realistic branch prediction, realistic memory latency, and thread dependencies on exploitable ILP. Our examination shows that theses benchmarks differ vastly from one another. As a result, we expect that no single, homogeneous, micro-architecture will work optimally for all, arguing for reconfigurable, heterogeneous designs. In the third part of this thesis, we use our novel simulator DotSim to study the benefits of prefetching shared memory within critical sections. In this chapter we calculate the upper bound of performance under our given constraints. Our intent is to provide motivation for new techniques to exploit the potential benefits of reducing latency of shared memory among threads. We conduct an idealized workload characterization study focusing on the data that is truly shared among threads, using a simplified memory model. We explore the degree of shared memory criticality, and characterize the benefits of being able to use latency reducing techniques to reduce execution time and increase ILP. We find that on average true sharing among benchmarks is quite low compared to overall memory accesses on the critical path and overall program. We also find that truly shared memory between threads does not affect the critical path for the majority of benchmarks, and when it does the impact is less than 1%. Therefore, we conclude that it is not worth exploring latency reducing techniques of truly shared memory within critical sections

Oil Produktion Affected by ASP and Gelation Technologies

Проведено аналіз впливу технологій внесення інгібітору корозії ASP і технологій огелювання на рівень нафтовидобутку. Показано, що технології огелювання були розроблені для забезпечення більш ефективного вертикального розгорнення, для затоплення природно тріщинуватих порід-колекторів нафти. Наведено результати аналізу ефективності використання комбінації цих двох технологій, які, на думку автора, могли б розширити застосовність лужного поверхнево-полімерного заводнення.Gelation technologies have been developed to provide more efficient vertical sweep efficiencies for flooding naturally fractured oil reservoirs or more efficient areal sweep efficiency for those with high permeability contrast «thief zones». The field proven alkaline-surfactant-polymer technology economically recovers 15% to 25% OOIP more oil than water flooding from swept pore space of an oil reservoir. However, alkaline-surfactant-polymer technology is not amenable to naturally fractured reservoirs or those with thief zones because much of injected solution bypasses target pore space containing oil. This work investigates whether combining these two technologies could broaden applicability of alkaline-surfactant-polymer flooding into these reservoirs. Aluminum citrate-polyacrylamide, resorcinol-formaldehyde, and the silicate-polyacrylamide gel systems did not produce significant incremental oil in linear core floods. Both flowing and rigid flowing chromium acetatepolyacrylamide gels and the xanthan gum-chromium acetate gel system produced incremental oil with the rigid flowing gel producing the greatest amount. Higher oil recovery could have been due to higher differential pressures across cores. None of the gels tested appeared to alter alkaline-surfactant-polymer solution oil recovery. Total water flood plus chemical flood oil recovery sequence recoveries were all similar

Optimum formulation of asp for injection in oil reservoir

Проведено аналіз оптимального складу інгібіторів корозії ASP для нагнітання у нафтовий пласт. Звертається увага на проблему додавання води в нафтовий резервуар, що є, на думку автора, єдиним методом відновлення тиску в резервуарі.Enhanced Oil Recovery is not a new process and it has been utilized by the Oil and Gas industry for several decades, particularly in the use of water flooding as a secondary recovery measure to ensure maintenance of reservoir pressure.1Adding water to an oil reservoir may seem an odd thing to do- anything added to the reservoir should aid in maintaining reservoir pressure, so why add water, as oil and water do not mix? The problem is that most oil reservoirs are solution gas driven, this means that as the oil is produced the reservoir pressure is reduced and the gas that was held in solution is released and expands. This process drives the oil to the producing wells, however the gas is also free to flow and be produced. Once the gas is produced, the reservoir's energy is lost and reservoir pressure is reduced. If this process is the only method of recovery, it will only yield up to 20% of the reservoirs total volume

A comparison of hydroponic and soil-based screening methods to identify salt tolerance in the field in barley

Success in breeding crops for yield and other quantitative traits depends on the use of methods to evaluate genotypes accurately under field conditions. Although many screening criteria have been suggested to distinguish between genotypes for their salt tolerance under controlled environmental conditions, there is a need to test these criteria in the field. In this study, the salt tolerance, ion concentrations, and accumulation of compatible solutes of genotypes of barley with a range of putative salt tolerance were investigated using three growing conditions (hydroponics, soil in pots, and natural saline field). Initially, 60 genotypes of barley were screened for their salt tolerance and uptake of Na+, Cl–, and K+ at 150 mM NaCl and, based on this, a subset of 15 genotypes was selected for testing in pots and in the field. Expression of salt tolerance in saline solution culture was not a reliable indicator of the differences in salt tolerance between barley plants that were evident in saline soil-based comparisons. Significant correlations were observed in the rankings of genotypes on the basis of their grain yield production at a moderately saline field site and their relative shoot growth in pots at ECe 7.2 [Spearman’s rank correlation (rs)=0.79] and ECe 15.3 (rs=0.82) and the crucial parameter of leaf Na+ (rs=0.72) and Cl– (rs=0.82) concentrations at ECe 7.2 dS m−1. This work has established screening procedures that correlated well with grain yield at sites with moderate levels of soil salinity. This study also showed that both salt exclusion and osmotic tolerance are involved in salt tolerance and that the relative importance of these traits may differ with the severity of the salt stress. In soil, ion exclusion tended to be more important at low to moderate levels of stress but osmotic stress became more important at higher stress levels. Salt exclusion coupled with a synthesis of organic solutes were shown to be important components of salt tolerance in the tolerant genotypes and further field tests of these plants under stress conditions will help to verify their potential utility in crop-improvement programmes

Additive effects of Na+ and Cl– ions on barley growth under salinity stress

Soil salinity affects large areas of the world’s cultivated land, causing significant reductions in crop yield. Despite the fact that most plants accumulate both sodium (Na+) and chloride (Cl–) ions in high concentrations in their shoot tissues when grown in saline soils, most research on salt tolerance in annual plants has focused on the toxic effects of Na+ accumulation. It has previously been suggested that Cl– toxicity may also be an important cause of growth reduction in barley plants. Here, the extent to which specific ion toxicities of Na+ and Cl– reduce the growth of barley grown in saline soils is shown under varying salinity treatments using four barley genotypes differing in their salt tolerance in solution and soil-based systems. High Na+, Cl–, and NaCl separately reduced the growth of barley, however, the reductions in growth and photosynthesis were greatest under NaCl stress and were mainly additive of the effects of Na+ and Cl– stress. The results demonstrated that Na+ and Cl– exclusion among barley genotypes are independent mechanisms and different genotypes expressed different combinations of the two mechanisms. High concentrations of Na+ reduced K+ and Ca2+ uptake and reduced photosynthesis mainly by reducing stomatal conductance. By comparison, high Cl– concentration reduced photosynthetic capacity due to non-stomatal effects: there was chlorophyll degradation, and a reduction in the actual quantum yield of PSII electron transport which was associated with both photochemical quenching and the efficiency of excitation energy capture. The results also showed that there are fundamental differences in salinity responses between soil and solution culture, and that the importance of the different mechanisms of salt damage varies according to the system under which the plants were grown

Multiple-Model Control of pH Neutralization Plant Using the SOM Neural Networks

Abstract: A multiple-model adaptive controller is developed using the Self-Organizing Map (SOM) neural network. The considered controller which we name it as Multiple Controller via SOM (MCSOM) is evaluated on the pH neutralization plant. An improved switching algorithm based on excitation level of plant has also been suggested for systems with noisy environments. Identification of pH plant using SOM is discussed and performance of the multiple-model controller is compared to the Self Tuning Regulator (STR) controller. I. INTORDUCTION There are many industrial processes which their nonlinear behavior can not be modeled and controlled by a single mathematical model at least in their full operating range. Various solutions for controlling these systems have been suggested over past decades. Robust and adaptive control is two major approaches toward solving this problem. But these techniques can become quite restrictive in many applications. A more recent approach is the concept of multiple models along with a switching algorithm [1] which has been an area of interest in control theory in order to simplify both the modeling and controller design. Many global controller designs with the aid of multiple models have been reported on different applications In this paper, a multi-model adaptive strategy with pole placement controllers is considered. Models have the same structure but parameter values are different for each model. To identify the bank of model, the multiple modeling using self-organizing map (MMSOM) The paper is organized as follows: First, multiple model control strategy is described. A brief description of SOM and its application on MMSOM in generation of model bank is presented in section 3. Simulation results from implementing the described control strategy on a simulated pH neutralization process are presented in section 4 and the paper is concluded in the final section. II. CONTROL BASED ON MULTIPLE MODELS A general diagram of the closed loop system is shown in are three weighting constants and M >1 determines the range of effective past data. Relative value of β α, weights the instantaneous and old estimation errors of models and λ is used as a forgetting factor for the past errors. In this manner the model corresponding to the lowest i J will be the best describing model at the time t. In order to avoid fast and unnecessary switches, a hysteresis function is added to the switching condition. The switch occurs only i