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Main Files:
- mm.{c,h}
- The malloc package
- mdriver.c
- The malloc driver that tests mm.c file
- Makefile
- Builds the driver
Approach:
- MALLOC: A dynamic memory allocator that maintains an area of a process's virtual memory known as the heap. In this approach, blocks are allocated by traversing an explicit, doubly linked list consisted of only free blocks to optimize search time. The first free block that will accomodate the requested size is chosen to be allocated.
- FREE: When the program frees a block, the explicit free list will add that block to the head of its list using doubly linked list node insertion methods.
- BLOCKS: The heap is 8-byte aligned. Each block begins with a header and ends with a footer that holds information on the size of the block and if it is free. To implement an explicit free list, each block also holds the address of the next and previous free block if it is free.
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free block: [header|previous_free_block|next_free_block|some_data|footer] - allocated block: [header|-------------------some_data-----------------|footer]
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- O(K) time, where k is the number of free blocks in the free list.
Evaluation:
- Performance Index = 0.6(Space Utilization) + 0.4 * min(1, throughput/throughput of libc malloc)
- Performance of this approach: 90/100
Other support files for the driver
- config.h
- Configures the malloc lab driver
- fsecs.{c,h}
- Wrapper function for the different timer packages
- clock.{c,h}
- Routines for accessing the Pentium and Alpha cycle counters
- fcyc.{c,h}
- Timer functions based on cycle counters
- ftimer.{c,h}
- Timer functions based on interval timers and gettimeofday()
- memlib.{c,h}
- Models the heap and sbrk function
Building and running the driver
- To build the driver, type "make" to the shell.
- To run the driver on a tiny test trace:
- unix> mdriver -V -f short1-bal.rep
- The -V option prints out helpful tracing and summary information.
- To get a list of the driver flags:
- unix> mdriver -h