Simulator

This program, malloc.py, allows you to see how a simple memory allocator works. Here are the options that you have at your disposal:

  -h, --help            show this help message and exit
  -s SEED, --seed=SEED  the random seed
  -S HEAPSIZE, --size=HEAPSIZE
                        size of the heap
  -b BASEADDR, --baseAddr=BASEADDR
                        base address of heap
  -H HEADERSIZE, --headerSize=HEADERSIZE
                        size of the header
  -a ALIGNMENT, --alignment=ALIGNMENT
                        align allocated units to size; -1->no align
  -p POLICY, --policy=POLICY
                        list search (BEST, WORST, FIRST)
  -l ORDER, --listOrder=ORDER
                        list order (ADDRSORT, SIZESORT+, SIZESORT-, INSERT-FRONT, INSERT-BACK)
  -C, --coalesce        coalesce the free list?
  -n OPSNUM, --numOps=OPSNUM
                        number of random ops to generate
  -r OPSRANGE, --range=OPSRANGE
                        max alloc size
  -P OPSPALLOC, --percentAlloc=OPSPALLOC
                        percent of ops that are allocs
  -A OPSLIST, --allocList=OPSLIST
                        instead of random, list of ops (+10,-0,etc)
  -c, --compute         compute answers for me

One way to use it is to have the program generate some random allocation/free operations and for you to see if you can figure out what the free list would look like, as well as the success or failure of each operation.

Here is a simple example:

prompt> ./malloc.py -S 100 -b 1000 -H 4 -a 4 -l ADDRSORT -p BEST -n 5 

ptr[0] = Alloc(3)  returned ?
List?

Free(ptr[0]) returned ?
List?

ptr[1] = Alloc(5)  returned ?
List?

Free(ptr[1]) returned ?
List?

ptr[2] = Alloc(8)  returned ?
List?

Try it out yourself in the terminal below!