Caches

A quick overview of how caches work, given at PyLadies Boston.

Transcript

1. CACHES the reason your computer is so darn fast
2. BASIC IDEA
3. BASIC IDEA Processor Bus Main Memory
4. BASIC IDEA Processor Bus* Main Memory *communication system that transfers data between components inside a computer*
5. BASIC IDEA Processor Cache Bus Main Memory
6. BASIC IDEA Processor Cache Bus Main Memory
7. BASIC IDEA Processor Cache Bus Main Memory
8. BASIC IDEA Processor Cache Bus Main Memory
9. BASIC IDEA Processor Cache Bus Main Memory
10. HOW DO THEY WORK?
11. DIRECT MAPPED Slot Valid Block Blocks Copied 0 0 1 0 2 0 3 0 4 0 0 5 0 6 0 7 0 8 0 Main Mem Addresses: 438 439 534 473 434 535
12. DIRECT MAPPED Tag Slot Block Offset 4 3 8 4 3 9 5 3 4 4 7 3 4 3 4 5 3 5 Main Mem Addresses: 438 439 534 473 434 535 First, we split the addresses:
13. DIRECT MAPPED Slot Valid Block Blocks Copied 0 0 1 0 2 0 3 1 4 430-439 4 0 0 5 0 6 0 7 0 8 0 Main Mem Addresses: 438 439 534 473 434 535 miss!
14. DIRECT MAPPED Slot Valid Block Blocks Copied 0 0 1 0 2 0 3 1 4 430-439 4 0 0 5 0 6 0 7 0 8 0 Main Mem Addresses: 438 439 534 473 434 535 miss! hit!
15. DIRECT MAPPED Slot Valid Block Blocks Copied 0 0 1 0 2 0 3 1 5 530-539 4 0 0 5 0 6 0 7 0 8 0 Main Mem Addresses: 438 439 534 473 434 535 miss! hit! miss!
16. DIRECT MAPPED Slot Valid Block Blocks Copied 0 0 1 0 2 0 3 1 5 530-539 4 0 0 5 0 6 0 7 1 4 470-479 8 0 Main Mem Addresses: 438 439 534 473 434 535 miss! hit! miss! miss!
17. DIRECT MAPPED Slot Valid Block Blocks Copied 0 0 1 0 2 0 3 1 4 430-439 4 0 0 5 0 6 0 7 1 4 470-479 8 0 Main Mem Addresses: 438 439 534 473 434 535 miss! hit! miss! miss! miss!
18. DIRECT MAPPED Slot Valid Block Blocks Copied 0 0 1 0 2 0 3 1 5 530-539 4 0 0 5 0 6 0 7 1 4 470-479 8 0 Main Mem Addresses: 438 439 534 473 434 535 miss! hit! miss! miss! miss! miss!
19. SET ASSOCIATIVE Slot Valid Block Blocks Copied 0 0 0 0 1 0 1 0 2 0 2 0 3 0 3 0 4 0 4 0 Main Mem Addresses: 438 439 534 403 434 535
20. SET ASSOCIATIVE Slot Valid Block Blocks Copied 0 0 0 0 1 0 1 0 2 0 2 0 3 1 4 430-439 3 0 4 0 4 0 Main Mem Addresses: 438 439 534 403 434 535 miss!
21. SET ASSOCIATIVE Slot Valid Block Blocks Copied 0 0 0 0 1 0 1 0 2 0 2 0 3 1 4 430-439 3 0 4 0 4 0 Main Mem Addresses: 438 439 534 403 434 535 miss! hit!
22. SET ASSOCIATIVE Slot Valid Block Blocks Copied 0 0 0 0 1 0 1 0 2 0 2 0 3 1 4 430-439 3 1 5 530-539 4 0 4 0 Main Mem Addresses: 438 439 534 403 434 535 miss! hit! miss!
23. SET ASSOCIATIVE Slot Valid Block Blocks Copied 0 0 4 400-409 0 0 1 0 1 0 2 0 2 0 3 1 4 430-439 3 1 5 530-539 4 0 4 0 Main Mem Addresses: 438 439 534 403 434 535 miss! hit! miss! miss!
24. SET ASSOCIATIVE Slot Valid Block Blocks Copied 0 0 4 400-409 0 0 1 0 1 0 2 0 2 0 3 1 4 430-439 3 1 5 530-539 4 0 4 0 Main Mem Addresses: 438 439 534 403 434 535 miss! hit! miss! miss! hit!
25. SET ASSOCIATIVE Slot Valid Block Blocks Copied 0 0 4 400-409 0 0 1 0 1 0 2 0 2 0 3 1 4 430-439 3 1 5 530-539 4 0 4 0 Main Mem Addresses: 438 439 534 403 434 535 miss! hit! miss! miss! hit! hit!