Modern Garbage Collectors provide performance improvements by increasing program locality to utilize the faster CPU cache. A common approach is to move objects together according to the mutators’ access order, which brings more relocations during GC. In most cases, more relocations would not impact performance when using concurrent Garbage Collectors such as ZGC. However, in constrained environments with fewer CPU cores or less memory, bad relocation performance will cause overall performance degradation. In this thesis, we investigated why larger objects do not benefit from better program locality, then proposed a new design to reduce the number of relocations by efficiently identifying and ignoring larger objects. As a result, the relocation performance can be improved. In constrained environments, this can lead to an increase in overall throughput. In the new design, we introduce an extra page type, the tiny page. If an object is considerably small that it could benefit from relocation, it will be placed on the tiny page when allocating. As a result, we could replace the time‐consuming size check of objects with a faster page type check. Memory fragmentation also can be reduced by this design. To evaluate this design, we add the size identification procedure into a locality improvement implementation named HCSGC. The results of benchmarks show a slight improvement in constrained environments. In the JGraphT benchmark, we see a 3‐5% speedup in different configurations with memory limitations. In the SPECjbb2015 benchmark, we see a ~1% increase in performance on average, but with overlapping confidence intervals. In the DaCapo benchmark suite, we see a 1% improvement in the sunflow benchmark with CPU constraint. For other benchmarks in DaCapo, no significant difference is discovered. The results suggest that the proposed new design is a feasible way of filtering out larger objects, and doing so can further improve the relocation and overall performance. / Modern Garbage Collector ger prestandaförbättringar genom att öka programplatsen för att använda den snabbare CPU‐cachen. En vanlig metod är att flytta fler objekt baserat på mutators åtkomstorder. I de flesta fall skulle fler omplaceringar inte påverka prestanda vid användning av samtidiga Garbage Collector som ZGC. Men i begränsade miljöer med färre CPU‐kärnor eller mindre minne kommer dålig flyttningsprestanda att leda till övergripande prestandaförsämring. I denna avhandling undersökte vi varför större objekt inte gynnas av bättre programplats, och föreslog sedan en ny design för att minska antalet flyttningar genom att effektivt identifiera och ignorera större objekt. Som ett resultat kan flyttningsprestandan förbättras. I begränsade miljöer kan detta leda till en ökning av den totala genomströmningen. I den nya designen introducerade vi en extra sidtyp, den lilla sidan. Om ett objekt är avsevärt litet som kan ha nytta av omplacering, kommer det att placeras på den lilla sidan vid allokeringen. Som ett resultat kan vi ersätta den tidskrävande storlekskontrollen av objekt med en snabbare sidtypskontroll. Minnesfragmentering kan också reduceras med denna design. För att utvärdera denna design lägger vi till storleksidentifieringsproceduren i en implementering av lokaliseringsförbättring som heter HCSGC. Resultaten av riktmärken visar en liten förbättring i begränsade miljöer. I JGraphT‐riktmärket ser vi en hastighet på 3‐ 5% i olika konfigurationer med minnesbegränsningar. I riktmärket SPECjbb2015 ser vi i genomsnitt en ~1% prestationsökning, men med överlappande konfidensintervall. I DaCapo ‐riktmärket ser vi en förbättring på 1% i solflödesriktmärket med CPU‐begränsning. För andra riktmärken i DaCapo upptäcks ingen signifikant skillnad. Resultaten tyder på att den föreslagna nya designen är ett genomförbart sätt att filtrera bort större objekt, och det kan ytterligare förbättra flytten och den övergripande prestandan.

Pointers in 64-bit architectures are unlikely to exhaust their vast address range, and are as such needlessly big. Reducing the amount of memory a pointer occupies leads to reduced memory demands, better usage of memory, and better locality. Pointer compression is a term that encompasses techniques that aim to make pointers occupy less memory, often to 32-bit for the sake of word alignment. Pointers that are 32-bit embody the opposite problem of having too restricted of an address range, being able to address only 4 GB. Z is a garbage collector in the HotSpot JVM which does not support pointer compression. Partly because the aforementioned address range restriction, and partly because the implementation of compressed pointers which exist in HotSpot would clash with the goals of the garbage collector. This project explores ways of implementing pointer compression for Z that isn't detrimental to the goals of the garbage collector, and aims to find where problems may occur. The outset was to explore compressing speculatively during runtime. The result is a design that relies on a custom bit layout for compressed pointers, inspecting bit layouts of the pointers on each read and write to detect the compression status. This seems to be the most promising in terms of code maintainability and ease of implementation.

As the development of hardware progresses, computers are expected to solve increasingly complex problems. However, solving more complex problems requires more complex software. To be able to develop these software systems, new programming languages with new features and higher abstraction levels are introduced. These features are designed to ease development, but sometimes they also make the runtime behavior unpredictable. Such features can not be used in real-time systems. A feature that traditionally has been unpredictable is garbage collection. Moreover, even though a garbage collector frees unused memory, almost all such methods require large amounts of additional memory. Garbage collection relieves developers of the responsibility to reclaim memory that is no longer used by the application. This is very tedious and error prone if done manually. Since garbage collection increases productivity and decreases programming errors, developers find it attractive, also in the real-time domain. This thesis presents a predictable garbage collection method, real-time reference counting, that increases memory efficiency by about 50 % compared to the most memory efficient previously presented predictable garbage collector. To increase performance, an optimization technique called object ownership that eliminates redundant reference count updates is presented. Object ownership is designed for reference counters, but can also be used to increase the performance of other incremental garbage collectors. Finally, a static garbage collector is presented. The static garbage collector can allocate objects statically or on the runtime stack, and insert explicit instructions to reclaim memory allocated on the heap. It makes it possible to eliminate the need for runtime garbage collection for a large class of Java applications. The static garbage collection method can also be used to remove costly synchronization instructions. Competing static garbage collection methods with reasonable analysis time are restricted to stack allocation, and thus handle a smaller class of applications.

This thesis deals with the designing of a garbage collector for the PNtalk virtual machine. It describes and rates the approaches and algorithms for an automatic memory management. Four algorithm families ale presented: mark-sweep, mark-compact, copying algorithms and reference counting. At first it describes sequential forms, that pauses running of the main program (mutator), then it describes parallel and concurent forms, that do not pauses the mutator. The thesis also presents generational model of garbage collecting. The following sections briefly introduces object orientated Petri nets. The result of this thesis is the design of the generational garbage collector for the PNtalk virtual machine.

The aim of this master's thesis is to design and implement JavaScript interpreter which is designed for purposes of avoiding obfuscation code of various types of computer viruses. This master's thesis also comprises a detailed view into the inner mechanism of the ECMAScript standard.

Java is one of the more recent programming languages that in runtime free applications from manual memory management by using automatic Garbage collector (GC) threads. Although, at the cost of stop-the-world pauses that pauses the whole application. Since the initial GC algorithms new collectors has been developed to improve the performance of Java applications. Still, memory related errors occurs and developers struggle to pick the correct GC for each specific case. Since the concept of microservices were established the benefits of using it over a monolith system has been brought to attention but there are still problems to solve, some associated to garbage collectors. In this study the performance of garbage collectors are evaluated and compared in a microservice environment. The measurements were conducted in a Java SpringBoot application using Docker and a docker compose file to simulate a microservice environment. The application outputted log files that were parsed into reports which were used as a basis for the analysis. The tests were conducted both with and without a database connection. Final evaluations show that one GC does not fit all application environments. ZGC and Shenandoah GC was proven to perform very good regarding lowering latency, although not being able to handle the a microservice environment as good as CMS. ZGC were not able to handle the database connection tests at all while CMS performed unexpectedly well. Finally, the study enlightens the importance of balancing between memory and hardware usage when choosing what GC to use for each specific case.

O problema de investigação que originou esta tese foi o questionamento acerca de quais competências devem constituir o perfil de empreendedores dedicados à gestão de empreendimentos populares solidários. O estudo foi realizado com participantes de cooperativas de coleta e tratamentos de resíduos sólidos, buscando identificar, descrever e analisar as competências que melhor contribuem para que essas pessoas consigam dedicar-se aos processos de trabalho próprios dessas cooperativas, mas também exercerem funções administrativas e gerenciais que são essenciais à sobrevivência do empreendimento. Essas cooperativas integraram o Projeto de Implantação da Incubadora de Empreendimentos Solidários de São Bernardo do Campo, o que permitiu analisar se e como esse processo de incubação contribuiu para o desenvolvimento do perfil de competências desses empreendedores. O objeto de pesquisa dessa investigação foram os catadores participantes dessas cooperativas de coleta e tratamento de resíduos sólidos recicláveis que são acompanhadas pelo projeto, na região do Grande ABC Paulista. Foi realizada uma pesquisa de caráter exploratório e descritivo, com a utilização do método qualitativo do estudo de caso, com análise documental, entrevistas e a técnica etnográfica da observação participante. A problemática da pobreza, a desigualdade social e as iniciativas públicas, privadas e do terceiro setor visando criar oportunidades de trabalho e renda para os mais pobres no Brasil, constituem o pano de fundo dessa pesquisa. Os resultados apontam que as organizações solidárias necessitam das competências individuais para sua sustentação e que essas competências podem ser desenvolvidas em processos de incubação como esse que é apresentado no presente estudo. Os empreendimentos solidários são organizações que não possuem como objetivo estratégico o lucro e sim a remuneração regular daqueles que neles trabalham como associados e o fortalecimento das relações intragrupais com o desenvolvimento da confiança e da cooperação. Nesse sentido, para compreender esses empreendimentos e o desempenho de seus integrantes é necessário considerar duas dimensões da sua dinâmica, o empreendedorismo e a solidariedade que se sustentam sobre as competências das pessoas que lá trabalham. / The research problem that gave rise to this thesis was the question about which competencies should be the profile of entrepreneurs dedicated to the management of popular solidarity enterprises. The study was conducted with participants from the collection and treatment of solid waste cooperatives , seeking to identify, describe and analyze the capacities that better contribute to that these people are able to devote himself to the work processes of these cooperatives , but also exercise administrative and managerial functions that are essential to the survival of the enterprise . These cooperatives have integrated the Project Implementation of the Entrepreneurial Incubator Solidarity of São Bernardo do Campo , which allowed us to analyze if and how this incubation process contributed to the development of the competencies profile of these entrepreneurs. The research object of this investigation were the participants collectors such collection and processing of recyclable solid waste cooperative that is accompanied by the project, in the Greater ABC Paulista region. An exploratory and descriptive research, using the qualitative method of case study to document analysis, interviews and ethnographic technique of participant observation was conducted. The problems of poverty, social inequality and public, private and third sector initiatives aimed at creating job opportunities and income for the poorest people in Brazil, is the background of this research. The results indicate that the solidarity organizations require individual competences for their support and that these capacities can be developed in incubation processes like this that is presented in this study. The solidarity enterprises are organizations that do not have as a strategic motive the profit, but the regular remuneration of those who work in them as associates and strengthening of intragroup relationships with the development of trust and cooperation. Accordingly, to study them is necessary to consider a dimension of entrepreneurship and other associations of which they sustained on the skills of the people working there.

A geração indiscriminada dos resíduos sólidos urbanos pode ser considerada como um dos grandes problemas das sociedades contemporâneas. Por meio deles se identificam os hábitos de consumo e as relações de produção da sociedade, bem como, constata-se que parcelas significativas da população buscam aí a sua fonte de sobrevivência. Entre essas pessoas, encontram-se os catadores de materiais recicláveis que, atualmente, na cidade de Porto Alegre, podem ser divididos em 2 categorias: os catadores dos galpões de reciclagem ou catadores formais, e os catadores de rua ou catadores informais, que carregam além das suas próprias histórias, a história do destino dos resíduos gerados pela sociedade. Esta pesquisa aborda a temática da gestão dos resíduos sólidos urbanos, enfatizando o papel dos catadores de materiais recicláveis, na cidade de Porto Alegre, considerando a necessidade de dar visibilidade a esses sujeitos como protagonistas dentro do processo de gerenciamento dos resíduos sólidos urbanos. As ferramentas teóricas utilizadas para aprofundar e refletir acerca desse contexto utilizam-se de conceitos como: espaço urbano, cidade, redes, relações de poder, movimentos sociais e os circuitos da economia, buscando promover um diálogo entre as mesmas, na perspectiva de compreender a complexa realidade na qual estão imersos os catadores de materiais recicláveis nos grandes centros urbanos. No sentido de contemplar o exposto anteriormente, realizou-se uma contextualização dos resíduos sólidos urbanos, enfocando os catadores de materiais recicláveis, por meio de uma revisão bibliográfica. Posteriormente foi proposta a análise de um dos atores, também centrais, nessa temática, representado pelo poder público. Realizou-se, também, um estudo de caso junto à Associação de Reciclagem Ecológica da Vila dos Papeleiros (AREVIPA), entendendo ser esse espaço diferenciado, na medida em que congrega, ao mesmo tempo, a existência dos dois grupos de catadores mencionados: os formais e os informais e a interferência direta dos atravessadores e o poder público nesse local. Concluiu-se demarcando algumas sugestões e reflexões, na perspectiva de responder aos objetivos propostos na pesquisa, inserindo o sujeito-catador como protagonista, no cenário dos resíduos sólidos urbanos, no sentido de colaborar com a construção de políticas públicas nesta área. / The wholesale production of urban solid residues can be consider as one of the big problems of the contemporary societies. Through these problems it´s possible identify the consumption habities and the society´s production relations, as well as, evidence that meaning allotments of the population look for here their source of survival. Among these people find the of recyclable materials collectors that, nowadays, in the Porto Alegre city, can be divided in 2 categories: the collectors of sheds or formal collectors and the street collectors or informal collectors, who carry besides their own history, the destination residues history produced by society. This research contemplate the urban solid residues management thematic, emphasizing the recyclable materials collectors, in Porto Alegre city, considering need to give visibility to this people as principa, inside of the urban solid residues management process. The theoretical tools used to deepen and thinking over this context using conceptions as: space, urban space, city, nets, power relations, social movements and the circuits of economy, looking for promoving a dialog among the sames, in perspective of understanding tha complex reality in what are immersed tha recyclable materials collectors in big urban centers. On sense of contemplating what was previously showed, realized a contextualization of tha urban solid residues, focusing the recyclable material collectors, through a bibliografic revision. Afterwards it was proposed the analysis of tha actors, also important, on this thematic, represented by power public. Realized, also, a study of case together with Vila dos Papeleiros Ecological Recycling Association (AREVIPA), understanding to be this a differentiated space, insofar as congregates, at the same time, the existence of two groups of mentioned collectors: the formal and informal collectors and the direct interference of crossers and public power on this place. Marking out some suggestions and thought, concluded, in so far as answering to objects proposed on resourch, inserting the customer-catador as principal, in urban solid residues scenery, in sense of colaborating with the construction of public policies in this area.

A geração indiscriminada dos resíduos sólidos urbanos pode ser considerada como um dos grandes problemas das sociedades contemporâneas. Por meio deles se identificam os hábitos de consumo e as relações de produção da sociedade, bem como, constata-se que parcelas significativas da população buscam aí a sua fonte de sobrevivência. Entre essas pessoas, encontram-se os catadores de materiais recicláveis que, atualmente, na cidade de Porto Alegre, podem ser divididos em 2 categorias: os catadores dos galpões de reciclagem ou catadores formais, e os catadores de rua ou catadores informais, que carregam além das suas próprias histórias, a história do destino dos resíduos gerados pela sociedade. Esta pesquisa aborda a temática da gestão dos resíduos sólidos urbanos, enfatizando o papel dos catadores de materiais recicláveis, na cidade de Porto Alegre, considerando a necessidade de dar visibilidade a esses sujeitos como protagonistas dentro do processo de gerenciamento dos resíduos sólidos urbanos. As ferramentas teóricas utilizadas para aprofundar e refletir acerca desse contexto utilizam-se de conceitos como: espaço urbano, cidade, redes, relações de poder, movimentos sociais e os circuitos da economia, buscando promover um diálogo entre as mesmas, na perspectiva de compreender a complexa realidade na qual estão imersos os catadores de materiais recicláveis nos grandes centros urbanos. No sentido de contemplar o exposto anteriormente, realizou-se uma contextualização dos resíduos sólidos urbanos, enfocando os catadores de materiais recicláveis, por meio de uma revisão bibliográfica. Posteriormente foi proposta a análise de um dos atores, também centrais, nessa temática, representado pelo poder público. Realizou-se, também, um estudo de caso junto à Associação de Reciclagem Ecológica da Vila dos Papeleiros (AREVIPA), entendendo ser esse espaço diferenciado, na medida em que congrega, ao mesmo tempo, a existência dos dois grupos de catadores mencionados: os formais e os informais e a interferência direta dos atravessadores e o poder público nesse local. Concluiu-se demarcando algumas sugestões e reflexões, na perspectiva de responder aos objetivos propostos na pesquisa, inserindo o sujeito-catador como protagonista, no cenário dos resíduos sólidos urbanos, no sentido de colaborar com a construção de políticas públicas nesta área. / The wholesale production of urban solid residues can be consider as one of the big problems of the contemporary societies. Through these problems it´s possible identify the consumption habities and the society´s production relations, as well as, evidence that meaning allotments of the population look for here their source of survival. Among these people find the of recyclable materials collectors that, nowadays, in the Porto Alegre city, can be divided in 2 categories: the collectors of sheds or formal collectors and the street collectors or informal collectors, who carry besides their own history, the destination residues history produced by society. This research contemplate the urban solid residues management thematic, emphasizing the recyclable materials collectors, in Porto Alegre city, considering need to give visibility to this people as principa, inside of the urban solid residues management process. The theoretical tools used to deepen and thinking over this context using conceptions as: space, urban space, city, nets, power relations, social movements and the circuits of economy, looking for promoving a dialog among the sames, in perspective of understanding tha complex reality in what are immersed tha recyclable materials collectors in big urban centers. On sense of contemplating what was previously showed, realized a contextualization of tha urban solid residues, focusing the recyclable material collectors, through a bibliografic revision. Afterwards it was proposed the analysis of tha actors, also important, on this thematic, represented by power public. Realized, also, a study of case together with Vila dos Papeleiros Ecological Recycling Association (AREVIPA), understanding to be this a differentiated space, insofar as congregates, at the same time, the existence of two groups of mentioned collectors: the formal and informal collectors and the direct interference of crossers and public power on this place. Marking out some suggestions and thought, concluded, in so far as answering to objects proposed on resourch, inserting the customer-catador as principal, in urban solid residues scenery, in sense of colaborating with the construction of public policies in this area.

A geração indiscriminada dos resíduos sólidos urbanos pode ser considerada como um dos grandes problemas das sociedades contemporâneas. Por meio deles se identificam os hábitos de consumo e as relações de produção da sociedade, bem como, constata-se que parcelas significativas da população buscam aí a sua fonte de sobrevivência. Entre essas pessoas, encontram-se os catadores de materiais recicláveis que, atualmente, na cidade de Porto Alegre, podem ser divididos em 2 categorias: os catadores dos galpões de reciclagem ou catadores formais, e os catadores de rua ou catadores informais, que carregam além das suas próprias histórias, a história do destino dos resíduos gerados pela sociedade. Esta pesquisa aborda a temática da gestão dos resíduos sólidos urbanos, enfatizando o papel dos catadores de materiais recicláveis, na cidade de Porto Alegre, considerando a necessidade de dar visibilidade a esses sujeitos como protagonistas dentro do processo de gerenciamento dos resíduos sólidos urbanos. As ferramentas teóricas utilizadas para aprofundar e refletir acerca desse contexto utilizam-se de conceitos como: espaço urbano, cidade, redes, relações de poder, movimentos sociais e os circuitos da economia, buscando promover um diálogo entre as mesmas, na perspectiva de compreender a complexa realidade na qual estão imersos os catadores de materiais recicláveis nos grandes centros urbanos. No sentido de contemplar o exposto anteriormente, realizou-se uma contextualização dos resíduos sólidos urbanos, enfocando os catadores de materiais recicláveis, por meio de uma revisão bibliográfica. Posteriormente foi proposta a análise de um dos atores, também centrais, nessa temática, representado pelo poder público. Realizou-se, também, um estudo de caso junto à Associação de Reciclagem Ecológica da Vila dos Papeleiros (AREVIPA), entendendo ser esse espaço diferenciado, na medida em que congrega, ao mesmo tempo, a existência dos dois grupos de catadores mencionados: os formais e os informais e a interferência direta dos atravessadores e o poder público nesse local. Concluiu-se demarcando algumas sugestões e reflexões, na perspectiva de responder aos objetivos propostos na pesquisa, inserindo o sujeito-catador como protagonista, no cenário dos resíduos sólidos urbanos, no sentido de colaborar com a construção de políticas públicas nesta área. / The wholesale production of urban solid residues can be consider as one of the big problems of the contemporary societies. Through these problems it´s possible identify the consumption habities and the society´s production relations, as well as, evidence that meaning allotments of the population look for here their source of survival. Among these people find the of recyclable materials collectors that, nowadays, in the Porto Alegre city, can be divided in 2 categories: the collectors of sheds or formal collectors and the street collectors or informal collectors, who carry besides their own history, the destination residues history produced by society. This research contemplate the urban solid residues management thematic, emphasizing the recyclable materials collectors, in Porto Alegre city, considering need to give visibility to this people as principa, inside of the urban solid residues management process. The theoretical tools used to deepen and thinking over this context using conceptions as: space, urban space, city, nets, power relations, social movements and the circuits of economy, looking for promoving a dialog among the sames, in perspective of understanding tha complex reality in what are immersed tha recyclable materials collectors in big urban centers. On sense of contemplating what was previously showed, realized a contextualization of tha urban solid residues, focusing the recyclable material collectors, through a bibliografic revision. Afterwards it was proposed the analysis of tha actors, also important, on this thematic, represented by power public. Realized, also, a study of case together with Vila dos Papeleiros Ecological Recycling Association (AREVIPA), understanding to be this a differentiated space, insofar as congregates, at the same time, the existence of two groups of mentioned collectors: the formal and informal collectors and the direct interference of crossers and public power on this place. Marking out some suggestions and thought, concluded, in so far as answering to objects proposed on resourch, inserting the customer-catador as principal, in urban solid residues scenery, in sense of colaborating with the construction of public policies in this area.