Changeset 70df5f3 for doc/theses
- Timestamp:
- Jul 26, 2021, 11:08:22 PM (3 years ago)
- Branches:
- ADT, ast-experimental, enum, forall-pointer-decay, jacob/cs343-translation, master, new-ast-unique-expr, pthread-emulation, qualifiedEnum
- Children:
- 04141f8
- Parents:
- 866cad3
- File:
-
- 1 edited
Legend:
- Unmodified
- Added
- Removed
-
doc/theses/mubeen_zulfiqar_MMath/intro.tex
r866cad3 r70df5f3 24 24 \noindent 25 25 ==================== 26 27 \section{Introduction} 28 Dynamic memory allocation and management is one of the core features of C. It gives programmer the freedom to allocate, free, use, and manage dynamic memory himself. The programmer is not given the complete control of the dynamic memory management instead an interface of memory allocator is given to the progrmmer that can be used to allocate/free dynamic memory for the application's use. 29 30 Memory allocator is a layer between thr programmer and the system. Allocator gets dynamic memory from the system in heap/mmap area of application storage and manages it for programmer's use. 31 32 GNU C Library (FIX ME: cite this) provides an interchangeable memory allocator that can be replaced with a custom memory allocator that supports required features and fulfills application's custom needs. It also allows others to innovate in memory allocation and design their own memory allocator. GNU C Library has set guidelines that should be followed when designing a standalone memory allocator. GNU C Library requires new memory allocators to have atlease following set of functions in their allocator's interface: 33 34 \begin{itemize} 35 \item 36 malloc: it allocates and returns a chunk of dynamic memory of requested size (FIX ME: cite man page). 37 \item 38 calloc: it allocates and returns an array in dynamic memory of requested size (FIX ME: cite man page). 39 \item 40 realloc: it reallocates and returns an already allocated chunk of dynamic memory to a new size (FIX ME: cite man page). 41 \item 42 free: it frees an already allocated piece of dynamic memory (FIX ME: cite man page). 43 \end{itemize} 44 45 In addition to the above functions, GNU C Library also provides some more functions to increase the usability of the dynamic memory allocator. Most standalone allocators also provide all or some of the above additional functions. 46 47 \begin{itemize} 48 \item 49 aligned_alloc 50 \item 51 malloc_usable_size 52 \item 53 memalign 54 \item 55 posix_memalign 56 \item 57 pvalloc 58 \item 59 valloc 60 \end{itemize} 61 62 With the rise of concurrent applications, memory allocators should be able to fulfill dynamic memory requests from multiple threads in parallel without causing contention on shared resources. There needs to be a set of a standard benchmarks that can be used to evaluate an allocator's performance in different scenerios. 63 64 \section{Background} 65 66 \subsection{Memory Allocation} 67 With dynamic allocation being an important feature of C, there are many standalone memory allocators that have been designed for different purposes. For this thesis, we chose 7 of the most popular and widely used memory allocators. 68 69 \paragraph{dlmalloc} 70 dlmalloc (FIX ME: cite allocator) is a thread-safe allocator that is single threaded and single heap. dlmalloc maintains free-lists of different sizes to store freed dynamic memory. (FIX ME: cite wasik) 71 72 \paragraph{hoard} 73 Hoard (FIX ME: cite allocator) is a thread-safe allocator that is multi-threaded and using a heap layer framework. It has per-thred heaps that have thread-local free-lists, and a gloabl shared heap. (FIX ME: cite wasik) 74 75 \paragraph{jemalloc} 76 jemalloc (FIX ME: cite allocator) is a thread-safe allocator that uses multiple arenas. Each thread is assigned an arena. Each arena has chunks that contain contagious memory regions of same size. An arena has multiple chunks that contain regions of multiple sizes. 77 78 \paragraph{ptmalloc} 79 ptmalloc (FIX ME: cite allocator) is a modification of dlmalloc. It is a thread-safe multi-threaded memory allocator that uses multiple heaps. ptmalloc heap has similar design to dlmalloc's heap. 80 81 \paragraph{rpmalloc} 82 rpmalloc (FIX ME: cite allocator) is a thread-safe allocator that is multi-threaded and uses per-thread heap. Each heap has multiple size-classes and each size-calss contains memory regions of the relevant size. 83 84 \paragraph{tbb malloc} 85 tbb malloc (FIX ME: cite allocator) is a thread-safe allocator that is multi-threaded and uses private heap for each thread. Each private-heap has multiple bins of different sizes. Each bin contains free regions of the same size. 86 87 \paragraph{tc malloc} 88 tcmalloc (FIX ME: cite allocator) is a thread-safe allocator. It uses per-thread cache to store free objects that prevents contention on shared resources in multi-threaded application. A central free-list is used to refill per-thread cache when it gets empty. 89 90 \subsection{Benchmarks} 91 There are multiple benchmarks that are built individually and evaluate different aspects of a memory allocator. But, there is not standard set of benchamrks that can be used to evaluate multiple aspects of memory allocators. 92 93 \paragraph{threadtest} 94 (FIX ME: cite benchmark and hoard) Each thread repeatedly allocates and then deallocates 100,000 objects. Runtime of the benchmark evaluates its efficiency. 95 96 \paragraph{shbench} 97 (FIX ME: cite benchmark and hoard) Each thread allocates and randomly frees a number of random-sized objects. It is a stress test that also uses runtime to determine efficiency of the allocator. 98 99 \paragraph{larson} 100 (FIX ME: cite benchmark and hoard) Larson simulates a server environment. Multiple threads are created where each thread allocator and free a number of objects within a size range. Some objects are passed from threads to the child threads to free. It caluculates memory operations per second as an indicator of memory allocator's performance. 101 102 \section{Research Objectives} 103 Our research objective in this thesis is to: 104 105 \begin{itemize} 106 \item 107 Design a lightweight concurrent memory allocator with added features and usability that are currently not present in the other memory allocators. 108 \item 109 Design a suite of benchmarks to evalute multiple aspects of a memory allocator. 110 \end{itemize} 111 112 \section{An outline of the thesis} 113 LAST FIX ME: add outline at the end
Note: See TracChangeset
for help on using the changeset viewer.