Garbage Collection

Sanitation services still not fully cover the urban population and this leads to different types of pollution and affects the urban
landscape. This paper aims a geographical approach by highlighting territorial disparities in the Romanian counties regarding the urban population access to waste collection services and to examine the environmental issues. Statistical database processed by ascending hierarchical cluster analysis are mapped at the level of Romanian counties achieving a spatial-temporal analysis for the period 2003-2008. The paper also discuss about the current dysfunctions existing in urban waste management from Romania. Development of waste
management facilities are in the process of transition from a traditional system based only on landfilling towards an integrated waste management system which develops the recycling and recovery of waste generated. Romania as an EU member country must improve the quality of sanitation services. Each city must provide the full collection of municipal waste generated in order to eliminate the illegal dumping.
Keywords: waste management, sanitation services, urban population, territorial disparities

Low coverage of urban and rural population to waste collection services leads to various environmental threats caused by uncontrolled waste disposal. New EU regulations on waste management issues transposed into national laws have improved this sector, but, the population access to such services is still low compared to others new EU members. A multi-scale approach of this indicator is a necessary tool
for a proper analysis of this environmental issue. The maps reveal that Romanian development regions (NUTS 2) have the lowest coverage rates at EU level in 2008. Furthermore, major disparities are reflected between Romanian counties in 2010. Thematic maps outline a comparative analysis at national and regional scale (Romanian counties & cities and communes of North-East Region) between urban vs rural areas in 2010. These geographical approaches are necessary for a better
monitoring process of waste management sector.

O presente artigo analisou as circunstancias que levaram a cidade de Antofagasta, capital da Segunda Região no Chile, a uma situação crítica de saúde ambiental e conflito socioambiental. Se analisam as consequências
de como um má gestão dos resíduos sólidos urbanos (RSU) na cidade durante anos, derivou numa crise de saúde pública com presença e aumento de casos de cólera y norovirus. A partir dos fatos surgem movimentos sociais que procuram uma mudança estrutural da gestão do lixo, contrapondo os interesses do poder público. A pesquisa articulou a informação obtida de um levantamento bibliográfico de documentação cientifica, jornalística e a entrevista em profundidade de informante chave, que faz parte dos movimentos sociais aqui mencionados. A discussão pretende ser um aporte com uma visão diferente, a solução de um conflito que ainda esta em curso, dando tanto uma mirada crítica da situação como prática para as propostas, desde uma visão ecológica e social.

This paper elaborates the idea for building a self-sustained sensor system, a network composed of nodes implementing the Riemann Garbage Bin (RGB) model. Hence, the case study explores the potential of employing sensor enabled systems to improve on waste monitoring and management in public waste bins. The network consists of wireless nodes that use ultrasonic sensors to measure the empty space in the bins. The sensors periodically report the fill rate of the waste bins to a sensor gateway that is based on Long Rage Wide Area Network (LoRaWAN) protocol. For our LoRaWAN server and network cover we choose to use The Things Network (TTN). These fill rates would be monitored by a mobile or web application connected to the network server. The goal of this project is through the Internet of Things (IoT) to monitor all the waste bins in one city, to improve the garbage management by relocating resources and by giving insight to the public about this global health threating problem.

Public-private partnerships are increasingly being promoted in Tanzania and the central argument of this paper is that institutional framework of a given local authority determines the nature and character of the formation and operational performance of such partnerships. The paper focuses on the public-private partnerships established in the area of solid waste management in the City of Dar-es-Salaam, and more specifically on the incentives, constraints and transaction costs that affect garbage collection and disposal in the City. The paper concludes that there has been noticeable, albeit constrained, improvement in garbage collection and disposal in Dar-es-Salaam. The public-private partnerships would, however, benefit from improvements in by-laws, contractual arrangements, enforcement of by-laws and higher public awareness.

This study aims to examine Mamak Garbage Area and the residents in that neighbourhood within ecophobic discourse in terms of analysing why and how they have become the target of ecophobic psyche. Garbage areas in general constitute elemental bodies combining natural elements and human influences since these areas are human-made natural storage yards. Moreover, junkyards reflect the relationship between human and nonhuman encounters. However, when disastrous results are experienced, human beings simply blame nature itself for the wrongdoings of the human practices. Furthermore, ecophobia is also targeted towards the human bodies residing in the garbage areas and depending on garbage for their living. Moreover, similar to wild nature, those human bodies are also excluded from the civil order, contributing to the discursive deep clash between nature and culture.

The life cycle of basic food items was studied in order to discover the reasons for low landfill diversion rates of this material. Management failures at key points of the cycle were identified. Subjects of study were commercialization procedures of fruit and vegetables before consumption, consumption proper and after-consumption disposal procedures for food scraps in the Brazilian context. Before consumption, the rate of lost fruit and vegetables stood at 16 wt.% of the total quantity commercialized. During consumption by residents, the waste rate of food amounted to 9 wt.% of all collected household garbage. In the after-consumption sector of the cycle, biodegradables represented 72 wt.% of all household garbage collected by official means in a typical Brazilian town. The numbers produced clearly identified landfill diversion of biodegradables as a management problem. The authors experimented with original proactive administrative procedures designed to set landfill diversion targets. The occurrence of wasted fruit and vegetables at the wholesaler and retailer levels was identified. Remedies were proposed and tested to reduce this waste by at least 50%. In the after-consumption sector, the notion of divided garbage collection was developed and applied to test communities. It was shown that biodegradables may be collected separately from the rest of household waste. This resulted in a diversion potential of 100% for biodegradables alone and 77 wt.% for all collected household waste. The study produced a formal policy proposal to municipal administrations to avoid the need for tipping of biodegradable material.

This paper examines and analyses the historical development of Zimbabwean towns and cities with a view to tracing and understanding policy directions, urban spatial development trends and other factors such as population dynamics that may have led to the development of the present-day urban settlements in the country. The paper observes that whilst pre-colonial cities existed during the golden age of the Munhumutapa dynasty and empire, these had no influence on the modern town and city because they were too distant and their experiences had long been lost by the time the colonial town was introduced in the country, some four centuries later. Furthermore the paper observes that whilst policy may easily be changed or even reversed, it is a near impossibility to do the same with the spatial physical developments such as buildings and infrastructure – roads, water reticulation, sewerage reticulation and treatment works, railway lines, telecommunication lines and power lines. As a result...

THE WORLD BANK were collecting over 1,000 indicators, only three of which were common to all cities. This lack of standardization limits the ability of cities to observe trends, monitor process improvements, establish benchmarks, share best practices, or learn from each other. Moreover, data collection costs are often considerable for municipalities. T he Global City Indicators Program (GCIP) is a decentralized, city-led initiative that enables cities to measure, report, and improve their performance and quality of life, facilitate capacity building, and share best practices through an easy-to-use web portal. GCIP assists cities in providing support to decision makers in making informed policy decisions, in addition to enhancing government accountability to the public. An ISO standard for city indicators, which is currently in development, will facilitate comparability and verification across cities and over time. The GCIP was initiated by the World Bank and its partners and is now run by the Global City Indicators Facility, based at the University of Toronto, which oversees the development of indicators and assists cities to join the Program.

The paper explores the solid waste management issues in Bengaluru city. As of 2014, Bengaluru is the third most populous city of India, experiencing a huge growth in its massive population. The present population of Bengaluru city is 1,01,78,146 (As per 2011 census-males 4,401,299 and females 4,024,671 totalling 84,25, 970). There are 198 wards under the Bruhat Bengaluru Mahanagara Palike (BBMP). Every day Bangaloreans produce 35,000 metric tons of solid waste. There are different ways and means to collect the solid waste in the city. In Bengaluru city, every day 16,000 Garbage Disposal workers are paid by the BBMP. At present, many private agencies are also working in managing solid waste. The present study is exploring about the opinions of the municipal workers regarding the public's Municipal solid waste management practices in Bengaluru city. Introduction Urban centers are becoming a hub of wastes. Due to speedy urbanization and industrialization, urban wastes are increasing rampantly. Solid waste management is the basic service provided by the municipal administration. The quantity of waste generation in India is comparatively less than other under developed countries and much lower than the developed countries. Population size and geographical characteristics determine the waste production in India. The major reasons for the inadequacy and inefficiency in the waste management services are apathy of municipal authorities, no system of primary collection from the doorstep, irregular street sweeping (the sanitary workers have been forced to follow traditional method of short broom usage, hand carts, tricycle, etc.), waste storage depots (the traditional methods do not match with the primary collection and secondary waste storage system), improper waste transportation, and absence of community participation. The Energy and Resources Institute (TERI) has estimated that waste generation will exceed 260 million tons / year by 2047, and it will be more than five times the present level. Only in a few cities of India, the waste processing done properly. The majority of Indian cities do not follow the waste processing scientifically. The processing is done without segregation. In some of the towns, it would be appreciated that vermicompost is being produced from the processed waste. In fact, neglect of waste disposal leads to environment pollution and health hazards to the community. Various techniques and technologies exist for proper solid waste management in India. One of the oldest method followed in India is composting or vermin composting (through this natural organic manure is produced). The largest vermin compost plant in India is located in Bengaluru and produces 100 metric ton /day. The household collection of garbage and disposal is the long-term responsibility of the Bengaluru City Corporation. However, from the year 2000 onwards, Bengaluru City Corporation has instituted door-to-door collection of garbage by sanitary workers. In some localities, both door-to-door collection as well as municipal bin system is followed. To avoid garbage collecting on the roads, it is removed to the dustbins in the localities and door-to-door collection of garbage is encouraged. The latter practice has been made mandatory by the BBMP. Therefore, majority of the household waste is collected on a daily basis.

We present a novel dynamic analysis technique that finds real deadlocks in multi-threaded programs. Our technique runs in two stages. In the first stage, we use an imprecise dynamic analysis technique to find potential deadlocks in a multi-threaded program by observing an execution of the program. In the second stage, we control a random thread scheduler to create the potential deadlocks with high probability. Unlike other dynamic analysis techniques, our approach has the advantage that it does not give any false warnings. We have implemented the technique in a prototype tool for Java, and have experimented on a number of large multi-threaded Java programs. We report a number of previously known and unknown real deadlocks that were found in these benchmarks.

The effects of offering monetary incentives for performing environmentally desirable behaviours are investigated in the context of a pay-by-weight scheme for garbage collection. Effects on different types of recycling and on the motivation behind recycling are investigated in a field setting based on a random sample ( n = 1,955) drawn from two groups of three matched municipalities, where households in one group pay a fixed fee for garbage collection and in the other a fee depending on the weight of their garbage. The study shows that the latter group delivers more material to recycling and composts more in the garden. A substantial proportion of the effect is mediated through perceived self-efficacy and personal norms. The results are consistent with the proposition that government regulation communicates norms and responsibilities and therefore can enhance internalized motivation in the form of a moral norm.

Reversible logic is one of the most vital issue at present time and it has different areas for its application, those are low power CMOS, quantum computing, nanotechnology, cryptography, optical computing, DNA computing, digital signal processing (DSP), quantum dot cellular automata, communication, computer graphics. It is not possible to realize quantum computing without implementation of reversible logic. The main purposes of designing reversible logic are to decrease quantum cost, depth of the circuits and the number of garbage outputs. In this paper, we have proposed a new reversible gate. And we have designed RS flip flop and D flip flop by using our proposed gate and Peres gate. The proposed designs are better than the existing proposed ones in terms of number of reversible gates and garbage outputs. So, this realization is more efficient and less costly than other realizations.

Dynamic storage allocation is an important part of a large class of computer programs written in C and C++. High-performance algorithms for dynamic storage allocation have been, and will continue to be, of considerable interest. This paper presents detailed measurements of the cost of dynamic storage allocation in 11 diverse C and C++ programs using ve very di erent dynamic storage allocation implementations, including a conservative garbage collection algorithm. Four of the allocator implementations measured are publicly-available on the Internet. A number of the programs used in these measurements are also available on the Internet to facilitate further research in dynamic storage allocation. Finally, the data presented in this paper is an abbreviated version of more extensive statistics that are also publically-available on the Internet.

The availability of high-speed solid-state storage has introduced a new tier into the storage hierarchy. Low-latency and high-IOPS solid-state drives (SSDs) cache data in front of high-capacity disks. However, most existing SSDs are designed to be a drop-in disk replacement, and hence are mismatched for use as a cache.

A real-time garbage collector has to fulfill two conflicting properties: avoid heap fragmentation and provide short blocking time. The heap needs to be compacted to avoid probably unbounded fragmentation. During compaction all objects are copied; copying is usually performed atomically to avoid interference with mutator threads. Copying of large objects and especially large arrays introduces long blocking times that are unacceptable for real-time systems.

Lebanon has witnessed in 2015 a severe trash crisis that had serious health and environmental impacts. Trash crisis has recently evolved, and is mostly related to inefficiency in networking, political leadership, and strategic management system and information flow. Trash crisis can be avoided with effective crisis management plan and waste management strategies. The latter is gaining broader attention , especially in the developing countries, with waste management being not well implemented. Until now, no studies have been conducted to measure and evaluate the impacts of the garbage crisis on the Lebanese tourism industry, which is a main income generator sector. Therefore, this research seeks to examine how tourism organizations, especially hotels as main producer of solid waste, are managing their waste to reduce the impacts of the crisis and to understand visitors' perceptions of solid waste management strategies adopted by hotels. 18 hotels' managers in Beirut were interviewed and 124 questionnaires were filled by hotels' guests, who were randomly selected in different areas of the capital. Results revealed that large hotels tend to effectively manage their solid waste which allowed them to overcome the crisis with minimal negative impacts. For the majority of respondents, selecting hotels is not primarily influenced by the implementation of solid waste management strategies. Moreover, results showed that 46% of respondents have hesitated to visit Lebanon during the crisis.

Garbage Collection (GC) is a core feature of multiple modern technologies (e.g., Java, Android). On one hand, it offers significant software engineering benefits over explicitly memory management, like preventing most types of memory leaks. On the other hand, GC is a known cause of performance degradation. However, it is considerably challenging to understand its exact impact on the overall application performance. This is because the non-deterministic nature of GC makes very complex to properly model it and evaluate its performance impacts. To help tackling these problems, we present an engine to generate realistic GC benchmarks by enabling to effectively capture the GC/memory behaviours experienced by real-world Java applications. We also demonstrate, through a comprehensive experimental evaluation, how such benchmarks can be useful to strengthen the evaluation of GC-related advancements.

Programmers are writing a large and rapidly growing number of programs in object-oriented languages such as Java that require garbage collection (GC). To explore the design and evaluation of GC algorithms quickly, researchers are using simulation based on traces of object allocation and lifetime behavior. The brute force method generates perfect traces using a whole-heap GC at every potential GC point in the program. Because this process is prohibitively expensive, researchers often use granulated traces by collecting only periodically, e.g., every 32K bytes of allocation.

Squeak is an open, highly-portable Smalltalk implementation whose virtual machine is written entirely in Smalltalk, making it easy to debug, analyze, and change. To achieve practical performance, a translator produces an equivalent C program whose performance is comparable to commercial Smalltalks.

Implementing a new programming language by the means of a translator to an existing language is attractive as it provides portability over all platforms supported by the host language and reduces the development time as many low-level tasks can be delegated to the host compiler. The C and C++ programming languages are popular choices for many language implementations due to the availability of efficient compilers on many platforms, and good portability. For garbage-collected languages, however, they are not a perfect match as they provide no support for accurately discovering pointers to heap-allocated data. We evaluate the published techniques, and propose a new mechanism, lazy pointer stacks, for performing accurate garbage collection in such uncooperative environments. We implemented the new technique in the Ovm Java virtual machine with our own Java-to-C++ compiler and GCC as a back-end, and found that our technique outperforms existing approaches.

A Java virtual machine (JVM) typically manages large amounts of class metadata (e.g. class descriptors, methods, byte codes) in main-memory. In this paper, we analyze the impact of metadata memory management on garbage collection costs in an industrialstrength JVM. We show that, for most applications in the latest DaCapo benchmark suite, the tracing of class metadata accounts for a significant part of full collection time.

Garbage collection yields numerous software engineering benefits, but its quantitative impact on performance remains elusive. One can compare the cost of conservative garbage collection to explicit memory management in C/C++ programs by linking in an appropriate collector. This kind of direct comparison is not possible for languages designed for garbage collection (e.g., Java), because programs in these languages naturally do not contain calls to free. Thus, the actual gap between the time and space performance of explicit memory management and precise, copying garbage collection remains unknown.

This paper objective to show the project standards concepts, being emphasize out its great importance and applicability in the software area. A case study it is carried through on four different applied project standards to the Garbage Collector. This paper is divided of the following form: in section 1, the basic concepts on Patterns and Design Patterns with emphasis in the solutions of project for software are introduced; in section 2 the Garbage Collector is described, in whose solution the use of standards can be applied; in section 3 the four standards used in the solution are described on the proposal solution: adapter, facade, iterator and proxy and; in the fourth and last section is described an a proposal of standards application on the solution of the described problem in section 2.

Java is a strong player in the application server market and thus the performance of its virtual machine is an important aspect of a server's performance. One of the components that affect the performance of a JVM is the memory manager, which also includes the garbage collector. Modern virtual machines offer a multitude of options for tuning the memory manager, which can have a significant impact on server application performance. In this paper, we examine the effect of tuning the garbage collection in an application server ...

Current FTL schemes have inevitable limitations in terms of memory requirement, performance, garbage collection overhead, and scalability. To overcome these limitations, we propose a workload adaptive flash translation layer referred to as WAFTL. WAFTL explores either page-level or block-level address mapping for normal data block based on access patterns. Page Mapping Block (PMB) is used to store random data and handle large number of partial updates. Block Mapping Block (BMB) is utilized to store sequential data and lower overall mapping table. PMB or BMB is allocated on demand and the number of PMB or BMB eventually depends on workload. An efficient address mapping is designed to reduce overall mapping table and quickly conduct address translation. WAFTL explores a small part of flash space as Buffer Zone to log writes sequentially and migrate data into BMB or PMB based on threshold. Static and dynamic threshold setting are proposed to balance performance and mapping table size. WAFTL has been extensively evaluated under various enterprise workloads. Benchmark results conclusively demonstrate that proposed WAFTL is workload adaptive and achieves up to 80% performance improvement, 83% garbage collection overhead reduction and 50% mapping table reduction compared to existing FTL schemes.

Today more and more functionality is packed into all kinds of embedded systems, making high-level languages, such as Java, increasingly attractive as implementation languages. However, certain aspects, essential to high-level languages are much harder to address in a low performance, small embedded system than on a desktop computer. One of these aspects is memory management with garbage collection. This paper describes the design process behind a concurrent, garbage collector unit (GCU), a coprocessor to the Java Optimised Processor. The GCU, targeting small embedded real-time applications, implements a markcompact algorithm, extended with concurrency support, and tuned for improved performance.

Concurrent and incremental collectors require barriers to ensure correct synchronisation between mutator and collector. The over- heads imposed by particular barriers on particular systems have been widely studied. Somewhat fewer studies have also compared barriers in terms of their termination properties or the volume of floating garbage they generate. Until now, the consequences for lo- cality of different barrier choices has not been studied, although lo- cality will be of increasing importance for emerging architectures. This paper provides a study of the locality of concurrent write bar- riers, independent of the processor architecture, virtual machine, compiler or garbage collection algorithm.

This paper presents an approach for performance analysis of modern enterprise-class server applications. In our experience, performance bottlenecks in these applications differ qualitatively from bottlenecks in smaller, stand-alone systems. Small applications and benchmarks often suffer from CPU-intensive hot spots. In contrast, enterprise-class multi-tier applications often suffer from problems that manifest not as hot spots, but as idle time indicating a lack of forward motion. Many factors can contribute to undesirable idle time, including locking problems, excessive system-level activities like garbage collection, various resource constraints, and problems driving load.

We present a memory management scheme for Java based on thread-local heaps. Assuming most objects are created and used by a single thread, it is desirable to free the memory manager from redundant synchronization for thread-local objects. Therefore, in our scheme each thread receives a partition of the heap in which it allocates its objects and in which it does local garbage collection without synchronization with other threads. We dynamically monitor to determine which objects are local and which are global. Furthermore, we suggest using profiling to identify allocation sites that almost exclusively allocate global objects, and allocate objects at these sites directly in a global area.

The Real-time Specification for Java and the upcoming, and more restricted, Safety Critical Java standard have been designed to allow programmers to avoid pauses caused by automatic memory management algorithms. Dynamic memory is user-managed using a region-based allocation scheme known as scoped memory areas. However, usage of those scoped memories is cumbersome and often leads to runtime errors. In this paper we focus on the safety critical subset of the Real-time Specification for Java and propose a real-time garbage collector that can be scheduled like a normal real-time thread with a deadline monotonic assigned priority. The restricted programming model offered by Safety Critical Java allows us to substantially simplify the collector. Our proposal has been implemented and evaluated in the context of the JOP project. JOP is a Java processor especially designed for embedded real-time systems. The architecture is optimized for worst-case execution time (WCET) instead of the usual optimization for average case execution time. Execution time of bytecodes is known cycle accurate.

One of the problems facing the use of Java for real-time environments with limited memory such as embedded systems is the unpredictability of running garbage collection. This introduces unexpected load on the system and causes undesirable delay for the real-time applications. In this ...

Solid-State Drives (SSDs) offer significant performance improvements over hard disk drives (HDD) on a number of workloads. The frequency of garbage collection (GC) activity is directly correlated with the pattern, frequency, and volume of write requests, and scheduling of GC is controlled by logic internal to the SSD. SSDs can exhibit significant performance degradations when garbage collection (GC) conflicts with an ongoing I/O request stream. When using SSDs in a RAID array, the lack of coordination of the local GC processes amplifies these performance degradations. No RAID controller or SSD available today has the technology to overcome this limitation. This paper presents Harmonia, a Global Garbage Collection (GGC) mechanism to improve response times and reduce performance variability for a RAID array of SSDs. Our proposal includes a high-level design of SSD-aware RAID controller and GGC-capable SSD devices, as well as algorithms to coordinate the global GC cycles. Our simulations show that this design improves response time and reduces performance variability for a wide variety of enterprise workloads. For bursty, write dominant workloads response time was improved by 69% while performance variability was reduced by 71%.

Heap size has a huge impact on the performance of garbage collected applications. A heap that barely meets the application's needs causes excessive GC overhead, while a heap that exceeds physical memory induces paging. Choosing the best heap size a priori is impossible in multiprogrammed environments, where physical memory allocations to processes change constantly. We present an automatic heap-sizing algorithm applicable to different garbage collectors with only modest changes. It relies on an analytical model and on detailed information from the virtual memory manager. The model characterizes the relation between collection algorithm, heap size, and footprint. The virtual memory manager tracks recent reference behavior, reporting the current footprint and allocation to the collector. The collector uses those values as inputs to its model to compute a heap size that maximizes throughput while minimizing paging. We show that our adaptive heap sizing algorithm can substantially reduce running time over fixed-sized heaps. total allocation of M pages, we define c § © max c M 2 , h § min h M 2 , and f i i h c .

CIDA-AIT Partnership, SEA-UEMA Project Asian Institute of Technology Pathumthani, Thailand iv Preface This publication is a summary of learnings of the gender mainstreaming process under the Southeast Asia Urban Environmental Management Applications (SEA-UEMA) project, implemented by Asian Institute of Technology (AIT) and supported by the Canadian International Development Agency (CIDA). SEA-UEMA supported a number of community-based demonstration projects and action research and conducted capacity building and networking activities. This publication describes the gender mainstreaming strategies and processes that were implemented during the seven years of the project and analyzes the successes achieved and challenges faced. Collections of project descriptions and cases where our analysis and learning have been most evident are included. Although most projects attempted to integrate gender perspectives, the results varied. The cases that have been included here are those that had clear evidence of the application of gender analysis and outcomes regarding gender equality. We found it important to highlight the gendered outcomes from different projects, since often times gendered outcomes were not noticed even by the project implementers.

Region-based memory management can offer improved time performance, relatively good memory locality and reuse, and also provide better adherence to real-time constraints during execution, when compared against traditional garbage collection. We have implemented a region-memory subsystem into the SSCLI 2.0 platform and also adapted an inference system to region-enable CIL programs, with the aid of newly introduced instructions. Results seem promising, as the programs running with regions have considerably smaller interrupting delays, compared to those running with garbage collection. Regions can bring runtime speed improvement of up to 50%, depending on how complicated are the data structures used in execution. The present work can also be viewed as an experience report based on our initiatory attempt at integrating a new region memory subsystem into a commercially developed shared source platform.

This paper studies the level 1 cache performance of Java programs by analyzing memory reference traces of the SPECjvm98 applications executed by the Latte Java Virtual Machine. We study in detail Java programs' cache performance of different access types in three JVM phases, under two execution modes, using three cache configurations and two application data sets. We observe that the poor data cache performance in the JIT execution mode is caused by code installation, when the data write miss rate in the execution engine can be as high as 70%. In addition, code installation also deteriorates instruction cache performance during execution of translated code. High cache miss rate in garbage collection is mainly caused by large working set and pointer chasing of the garbage collector. A larger data cache works better on eliminating data cache read misses than write misses, and is more efficient on improving cache performance in the execution engine than in the garbage collection. As application data set increases in the JIT execution mode, instruction cache and data cache write miss rates of the execution engine decrease, while data cache read miss rate of the execution engine increases. On the other hand, impact of varying data set on cache performance is not as pronounced in the interpreted mode as in the JIT mode.

Traditional approaches to enforcing memory safety of programs rely heavily on run-time checks of memory accesses and on garbage collection, both of which are unattractive for embedded applications. The goal of our work is to develop advanced compiler techniques for enforcing memory safety with minimal run-time overheads. In this paper, we describe a set of compiler techniques that, together with minor semantic restrictions on C programs and no new syntax, ensure memory safety and provide most of the error-detection capabilities of type-safe languages, without using garbage collection, and with no run-time software checks, (on systems with standard hardware support for memory management). The language permits arbitrary pointer-based data structures, explicit deallocation of dynamically allocated memory, and restricted array operations. One of the key results of this paper is a compiler technique that ensures that dereferencing dangling pointers to freed memory does not violate memory safety, without annotations, run-time checks, or garbage collection, and works for arbitrary type-safe C programs. Furthermore, we present a new interprocedural analysis for static array bounds checking under certain assumptions. For a diverse set of embedded C programs, we show that we are able to ensure memory safety of pointer and dynamic memory usage in all these programs with no run-time software checks (on systems with standard hardware memory protection), requiring only minor restructuring to conform to simple type restrictions. Static array bounds checking fails for roughly half the programs we study due to complex array references, and these are the only cases where explicit run-time software checks would be needed under our language and system assumptions.