Processor that uses 32-bit virtual addresses

Assignment 10

Note: Make reasonable assumptions where necessary and clearly state them. Feel free to
discuss problems with classmates, but the only written material that you may consult while
writing your solutions are the textbook and lecture slides/videos. Solutions should be
uploaded as a single pdf file on Canvas. Show your solution steps so you receive partial
credit for incorrect answers and we know you have understood the material. Don't just
show us the final answer.
1. Consider a processor that uses 32-bit virtual addresses and a 36-bit physical address.
Assume that the system uses 4KB pages.
What is the size of a program's virtual memory? (5 points)
What is the size of the system's physical memory? (5 points)
How many virtual pages does a program have? (5 points)
How many physical pages does the system have? (5 points)
2. Consider a 3-processor multiprocessor connected with a shared bus that has the
following properties: (i) centralized shared memory accessible with the bus, (ii)
snooping-based MSI cache coherence protocol, (iii) write-invalidate policy. Also
assume that the caches have a writeback policy. Initially, the caches all have invalid
data. The processors issue the following five requests, one after the other. Create a
table similar to that in slide 6 of lecture 25 to indicate what happens for every request.
(35 points)
P1: Read X
P1: Write X
P3: Read X
P2: Read X
P3: Write X
3. Consider a 3-processor multiprocessor connected with a scalable network that has the
following properties: (i) distributed memory organization, (ii) directory-based cache
coherence protocol, (iii) write-invalidate policy. Also assume that the caches have a
writeback policy. Initially, the caches all have invalid data. Assume that data X is stored
in the memory connected to processor P2. Create a table similar to that in slide 13 of
lecture 25 to indicate what happens for every request. (35 points)
P1: Read X
P1: Write X
P3: Read X
P2: Read X
P3: Write X
4. How can processors defend against the Meltdown attack? (10 points)