21 07 2022 E TS Silvano

Pagina 1

NAME SURNAME PERSONAL CODE ACA2022_EXAM_FORM2 Data: 21/07/2022 ACA2022_FORM2_21July2022_SILVANO ACA Course -- Prof. SILVANO FORM2 is composed of 6 QUESTIONS to get UP TO 12 POINTS Duration is 24 minutes! Question 1 (complete table format) 2 points Let’s consider the following access patterns on a 4-processor system with a direct-mapped, write-back cache with one cache block per processor and a two-cache block memory. Assume the MESI protocol is used, with write-back caches, write-allocate, and write-invalidate of other caches. Please COMPLETE the following table: Cycle After Operation P0 cache block state P1 cache block state P2 cache block state P3 cache block state Memory at bl. 0 up to date? Memory at bl. 1 up to date? 0 Initial state Invalid Invalid Invalid Invalid Yes Yes 1 P0: Read Bl. 1 Excl (1) Invalid Invalid Invalid Yes Yes 2 P2: Read Bl. 0 Excl (1) Invalid Excl (0) Invalid Yes Yes 3 P3: Read Bl. 0 4 P1: Write Bl. 0 5 P0: Write Bl. 1 6 P3: Read Bl. 1 7 P2: Read Bl. 0 NAME SURNAME PERSONAL CODE ACA2022_EXAM_FORM2 Data: 21/07/2022 Feedback Cycle After Operation P0 cache block state P1 cache block state P2 cache block state P3 cache block state Memory at bl. 0 up to date? Memory at bl. 1 up to date? 0 Initial state Invalid Invalid Invalid Invalid Yes Yes 1 P0: Read Bl. 1 Excl (1) Invalid Invalid Invalid Yes Yes 2 P2: Read Bl. 0 Excl (1) Invalid Excl (0) Invalid Yes Yes 3 P3: Read Bl. 0 Excl (1) Invalid Shared (0) Shared (0) Yes Yes 4 P1: Write Bl. 0 Excl (1) Mod (0) Invalid Invalid No Yes 5 P0: Write Bl. 1 Mod (1) Mod (0) Invalid Invalid No No 6 P3: Read Bl. 1 Shared (1) Mod (0) Invalid Shared (1) No Yes 7 P2: Read Bl. 0 Shared (1) Shared (0) Shared (0) Shared (1) Yes Yes See MESI protocols on the slides on L13: Multiprocessors. NAME SURNAME PERSONAL CODE…