Parallel_Systems_3 Shared Memory Machines 3. [2 points] Consider a shared address space architecture.  The address space is divided into two partitions:  Partition A is NCC-NUMA  Partition B is CC-NUMA  What guarantees are needed from the architecture to ensure that it provides sequential consistency memory model to the programmer? 

Potpourri_6a Potpourri 6. I/O ring data structures can be used to facilitate data transfer between paravirtualized guest OSs and the hypervisor. Consider a guest OS making a hypercall to the hypervisor to write some data to disk. The process begins with the guest making the write request, followed by the hypervisor processing the request and responding. Finally, the guest consumes this response.          a. [2 points] What information is conveyed by the guest OS via the I/O ring data structure when making the write request?

Parallel_Systems_8a LRPC 8. Consider a single processor machine running a client and server. The client calls a procedure ‘foo’ on the server with the following declaration:   void foo(data_structure a, data_structure b);     The server always expects the actual parameters of the call to be in its stack.     Consider the following variables representing average times to complete the described operations.  T1: Average time to copy a variable of type ‘data_structure’ from user space to kernel space and vice versa.  T2: Average time to copy a variable of type ‘data_structure’ from user space to user space.  T3: Average time the server takes to execute the procedure ‘foo’.  T4: Average time to switch between user-space domains (averaged over thread-doctored and normal thread-scheduled workflows).  T5: Average time for a kernel trap and associated validation (averaged over binding object and non-binding object workflows).     Answer the questions below based on the information and average times given above. You should give an explanation of the component times that make up your answer to get any credit. Consider any other time that is not mentioned above as negligible.    a. [2 point] Calculate the total client wait time after calling the procedure ‘foo’, if the server and client were collocated in the same process. 

Parallel_Systems_8b LRPC The context for this question is the same as the previous question. 8. Consider a single processor machine running a client and server. The client calls a procedure ‘foo’ on the server with the following declaration:   void foo(data_structure a, data_structure b);     The server always expects the actual parameters of the call to be in its stack.     Consider the following variables representing average times to complete the described operations.  T1: Average time to copy a variable of type ‘data_structure’ from user space to kernel space and vice versa.  T2: Average time to copy a variable of type ‘data_structure’ from user space to user space.  T3: Average time the server takes to execute the procedure ‘foo’.  T4: Average time to switch between user-space domains (averaged over thread-doctored and normal thread-scheduled workflows).  T5: Average time for a kernel trap and associated validation (averaged over binding object and non-binding object workflows).     Answer the questions below based on the information and average times given above. You should give an explanation of the component times that make up your answer to get any credit. Consider any other time that is not mentioned above as negligible.    b. [3 points] Calculate the total client wait time after calling the procedure ‘foo’, if the server and client were two different processes, and the OS does not optimize the RPC workflow for processes running on the same machine. 

Solve the proportion for the given variable. Round the solution where indicated.

Parallel_Systems_7 LRPC 7. [2 points] (Answer True/ False with justification) The kernel holds two procedure descriptors associated with Server A; one for procedure ‘foo’ with total number of simultaneous calls set to 5 and the other for procedure ‘bar’ with total number of simultaneous calls set to 6. Given that these are the only 2 procedures registered by this server, the total number of simultaneous RPCs that the server can field is max(5, 6) = 6.

Parallel_Systems_5c M.E.Lock The context for this question is the same as the previous question. 5. Consider the ticket lock algorithm from lecture 4 (slide 108): c. [1.5 points] What are the downsides of the ticket lock algorithm for systems with write-invalidate cache coherence? Briefly explain your answer.

Parallel_Systems_6 Barriers 6. [4 points] Given the following picture of the dissemination algorithm, focusing on node P4, what information does P4 know at the end of round 1?  Explain your answer. 

Virtualization_2 Full Virtualization 2. [4 points] In a fully virtualized environment, consider the following:  Two VMs are currently running. VM1 has 3 processes running; VM2 has 4 processes running.    Assume the size of the hardware page table is 1 MB.    What is the total memory overhead incurred by the Hypervisor for the above configuration? Show your work for any credit.

Parallel_Systems_1 Shared Memory Machines 1. [2 points] Consider a NCC-NUMA architecture for a shared address space multiprocessor.  What guarantees are needed from the architecture to ensure that it provides sequential consistency memory model to the programmer?