With the addition of the compute shader stage for GPGPU hardware it has becomepossible to run CPU like programs on modern GPU hardware. The greatest benefit can be seen for algorithms that are of highly parallel nature and in the case of volume rendering the Marching cubes algorithm makes for a great candidate due to its simplicity and parallel nature. For this thesis the Marching cubes algorithm was implemented on a compute shader and used in a DirectX 12 framework to determine if GPU frametime performance can be improved by executing the compute command queue parallell to the graphics command queue. Results from performance benchmarks show that a gain is present for each benchmarked configuration and the largest gains are seen for smaller workloads with up to 52%. This information could therefore prove useful for game developers who want to improve framerates or decrease development time but also in other fields such as volume rendering for medical images.

[pt] Este trabalho propõe a criação de um ambiente que dê suporte computacional ao desenvolvimento de sistemas multi- agentes, auxiliando o desenvolvedor durante o ciclo de vida de construção (da modelagem à implementação) destes sistemas. Estaremos utilizando o ANote como linguagem de modelagem para especificação e análise de sistemas multi-agentes e a arquitetura ASYNC para o processo de desenvolvimento. Ocorrendo assim, uma transformação dos diagramas do ANote para a arquitetura ASYNC. / [en] This work considers the creation of an environment that gives to computational support to the development of multi-agents systems, assisting the developer during the cycle of life of construction (the modeling to the implementation) of these systems. We will be using ANote as modeling language for specification and analysis of multi-agents systems and architecture ASYNC for the development process. Thus occurring, a transformation of the diagrams of ANote for architecture ASYNC.

Background. With the introduction of the compute shader, followed by the application programming interface (API) DirectX 12, the modern GPU is now going through a transformation. Previously the GPU was used as a massive computational tool for running a single task at unparalleled speed. The compute shader made it possible to run CPU like programs on the GPU, DirectX 12 takes this even further by introducing a multi-engine architecture. Multi-engine architecture unlocks the possibility of running the compute shader alongside the regular graphical stages, this concept is called asynchronous compute. Objectives. This thesis aims to investigate if asynchronous compute can be used to increase the performance of particle simulations. The key metrics being studied are total frame time, rendered frames per second, and overlap time. The frst two are used to determine if asynchronous compute improves performance or not, while the last is used to determine if the particle simulation is running asynchronous compute or not.Methods. For this thesis, the particle simulation used is the N-body particle simulation.The N-body particle simulation is implemented using a compute shader and is part of a larger DirectX 12 framework. One application is implemented that run two different execution models, one is the standard sequential execution model and one is the asynchronous compute model. The main difference between the two execution models is that the sequential execution model will be using only one command queue, this being a 3D command queue. The asynchronous compute model will be running a separate compute command queue alongside the 3D command queue. The performance metrics being studied are all collected using a custom-built GPU profiler. Results. The results indicate that it is possible to increase the performance of particle simulations using asynchronous compute. The registered performance gain reaches as high as 34% on hardware that supports asynchronous compute while hardware that according to NVIDIA does not support asynchronous compute registered performance gains up towards 11%. In terms of overlap time between the compute workload and the graphical workload, the AMD GPU showed an overlap time that matched the frame time. However, NVIDIA GPUs did not show the expected overlap time. Conclusions. It can be determined that asynchronous compute provide benefits when compared to the sequential execution model, it can be used to increase the performance of particle simulations. However, since the research in this thesis only made use of a single particle simulation, more work needs to be done, for example, work to test if the performance gain can be improved even further using different methods like, workload pairing or utilizing multiple GPUs, however that kind of work requires the use of a larger-scale application that consists of multiple different tasks other than just a single particle simulation. / Bakgrund. I och med Introduktionen av compute shadern, tätt följd av DirectX12, så genomgår den moderna GPUn en förvandling. Tidigare användes GPUn som ett massivt uträkningsverktyg ämnat att utföra en enda uppgift med en enastående hastighet. Compute shadern gjorde det möjligt at köra CPU liknande program på GPUn, DirectX 12 tar detta ett steg längre genom att introducera en multi-engine arkitektur. Denna arkitektur låser upp möjligheten att köra compute shadern samtidigt som de vanliga grafiska shader stadigerna, detta konceptet kallas asynchronous compute.Syfte. Syftet med denna avhandling är att undersöka om asynchronous compute kan användas för att öka prestandan på en partikel simulering. Den viktigaste data som kommer studeras är den totala frame tiden, antalet renderade frames varje sekund och överlapp tiden. Den totala frame tiden och antalet renderade frames varje sekund används för att bestämma om asynchronous compute faktiskt ökar prestandan eller inte, medan överlapp tiden används för att bestämma om partikel simuleringen kör asynchronous compute eller inte.Metod. Partikel simuleringen som används i denna avhandling är en N-body partikel simulering. N-body partikel simuleringen är implementerad i en compute shader och är en del av en större DirectX 12 applikation. En applikation implementeras som kör två olika exekverings modeller, den ena är den vanliga sekventiella exekverings modellen och den andra är asynchronous compute modellen. Den primära skillnaden mellan exekverings modellerna är att den sekventiella exekverings modellen bara använder sig av en kommando kö, vilken är en 3D kommando kö. Asynchronous compute modellen kommer använda sig av en separat compute kommando kö tillsammans med 3D kommando kön. Den metriska datan samlas in med hjälp av enegen byggd GPU profilerare.Resultat. Resultatet indikerar att det är möjligt att öka prestandan hos en partikelsimulering som använder sig av asynchronous compute. Den registrerade prestandaökningen når så högt som till 34% på hårdvara som stödjer asynchronous compute, medan hårdvara som inte stödjer asynchronous compute registrerade en prestandaökning upp till 11%. När det kommer till överlapp tiden mellan compute delen och den grafiska delen så visar GPUn från AMD en överlapp tid som matchar frame tiden. När det kommer till GPUerna från NVIDIA så visade dessa inte en förväntad överlapp tid.Slutsatser. Det kan fastställas att asynchronous compute har vissa fördelar jämfört med den sekventiella exekverings modellen. Asynchronous compute kan användas för att öka prestanda hos partikel simuleringar, men eftersom undersökningen i denna avhandling bara använder en enda partikel simulering så krävs ännu mera forskning. Exempelvis forskning som undersöker om prestanda ökningen kan bli ännu bättre, genom att applicera olika metoder som workload pairing och användingen av fera GPUer, detta krväver också att en större application för testing används, som består av fera olika typer av simuleringar och inte bara en enda partikel simuleing.

This study presents a hybrid concurrent programming model combining the previously developed Fork-Join model (FJM) and Actor model (AM). With the advent of multi-core computers, there is a renewed interest in programming models that reduce the burden of reasoning about and writing efficient concurrent programs. The proposed hybrid model shows how the divide-and-conquer approach of the FJM and the no-shared mutable state and event-driven philosophy of the AM can be combined to solve certain classes of problems more efficiently and productively than either of the aforementioned models individually. The hybrid model adds actor creation and coordination to into the FJM, while also enabling parallelization within actors. This study uses the Habanero-Java and Scala programming languages as the base for the FJM and AM respectively, and provides an implementation of the hybrid model as an extension of the Scala language called Habanero-Scala. The hybrid model adds to the foundations of parallel programs, and to the tools available for the programmer to aid in productivity and performance while developing parallel software.

The aim of my thesis is to provide a collection of examples about document oriented MongoDB database using Node.js platform, specifically using the Mongoose program, for object-document mapping (ODM). The aim is met by analysis of Mongoose and Async module, which provides functions for more comprehensive asynchronous querying, needed for working with input/output to the MongoDB database in Node.js. The main merit of this thesis is (in the general sense) a demonstration of how to create a administration part of web application (backend) in Node.js, applying document oriented MongoDB database. The thesis discusses, in the theoretical part, about characteristics and significance of document oriented MongoDB database, about characteristics and architecture of Node.js platform employing untyped and multiplatform JavaScript language and about object document mapping (ODM) programs for Node.js on MongoDB. The practical part contains a collection of examples, where in the first chapter introduces an instalation and execution manual of necessary programs. The next chapter is dedicated to simple examples of Mongoose module and in the last chapter there are stated the complex examples of Mongoose and Async modules, which are the main merits of this thesis.

Flaky tests are defined as tests that show non-deterministic outcomes, meaning they can show both passing and failing results without changes to the code. These tests cause a major problem in the software development process since it can be difficult to know if the cause of a failure originates from the production- or test code. Developers may choose to ignore failing tests known to be flaky when they might actually hide real bugs in the production code. This thesis investigates a specific category of flaky tests known as "Async Wait", which are tests that makes asynchronous calls to servers and other remote resources and fails to properly wait for the results to be returned. There are tools available for detecting flaky tests, but most of these need the test to be executed and operate on run time information. In order to detect potential flakiness in an even earlier state, this thesis looks in to if it is possible to predict flaky outcomes by analyzing only at the test code itself without running it. The scope is limited to the Async Wait only to determine in which cases and under what circumstances developing an algorithm to automatically detect these flaky tests would be possible in this category. Commits from open source projects on GitHub were scanned for Async Wait flaky tests with the intention of finding the characteristics of the asynchronous calls and how the waiting for them is handled as well as how the flakiness is resolved by developers in practice in order to see if the information in only the test code is enough to predict flaky behavior.

This thesis presents an algorithm for solving a subset of static analysis data flow problems known as Interprocedural Finite Distribute Subset problems. The algorithm, called IFDS-RA, is an implementation of the IFDS algorithm which is an algorithm for solving such problems. IFDS-RA is implemented using Reactive Async which is a deterministic, concurrent, programming model. The scalability of IFDS-RA is compared to the state-of-the-art Heros implementation of the IFDS algorithm and evaluated using three different taint analyses on one to eight processing cores. The results show that IFDS-RA performs better than Heros when using multiple cores. Additionally, the results show that Heros does not take advantage of multiple cores even if there are multiple cores available on the system. / Detta examensarbete presenterar en algoritm för att lösa en klass av problem i statisk analys känd som Interprocedural Finite Distribute Subset problem.  Algoritmen, IFDS-RA, är en implementation av IFDS algoritmen som är utvecklad för att lösa denna typ av problem. IFDS-RA använder sig av Reactive Async som är en deterministisk programmeringsmodell för samtida exekvering av program.  Prestendan evalueras genom att mäta exekveringstid för tre stycken taint analyser med en till åtta processorkärnor och jämförs med state-of-the-art implementationen Heros. Resultaten visar att IFDS-RA presterar bättre än Heros när de använder sig av flera processorkärnor samt att Heros inte använder sig av flera processorkärnor även om de finns tillgängliga.

This report discloses the implementation of a collaboration tool in the form of action plans and discussion functionality in behalf of the company ZonderaCom AB (Zondera). The current tool used for this purpose is inflexible, have a hard time meeting customer requirements and therefore needs to be replaced. The new application is part of a larger entity where user management and database schemas are already in place. The functionality of this application consists of issue management, chat/discussion, document management, notes, sharing and printing. For users with higher permissions a summary view will also be available. The application is implemented using ASP.NET Core MVC, Entity Framework (EF) and SQL Server as the database engine. A SPA-based approach is used where the UI (User Interface) is dynamically rendered and loaded via Ajax and partial views. The source code for the application is largely omitted from this report due to business reasons. Interface’s and database schemas are used to display code and database structure. / Denna rapport behandlar implementeringen av ett samarbetsverktyg i form av handlingsplaner och diskussion till företaget ZonderaCom AB (Zondera). Det verktyg som använts tidigare i detta syfta är oflexibelt, har svårt att uppnå återkommande kundkrav och behöver därför bytas ut. Applikationen är en del av en större helhet där användarhantering och databas redan finns på plats. I applikationen ska funktionalitet för aktivitetshantering, chatt/diskussion, dokumentuppladdning, anteckningar, delning och utskrift implementeras. För användare med högre behörighet ska även en administrativ översikt finnas tillgänglig. Applikationen implementeras med hjälp av ASP.NET Core MVC, Entity Framework (EF) och SQL Server som databasmotor. Ett SPA-baserat angreppsätt används där gränssnitt laddas dynamiskt via Ajax och partial views. Källkod för applikationen och implementering på detaljnivå har till största del utelämnats ur denna rapport av affärsmässiga skäl. Interface och databasscheman används för att visa kod- och databasstruktur.