In memory 7 handler returns to original process

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Unformatted text preview: r data references And a hit in the L1 cache sKll requires 1-­‐3 cycles What can we do to make this faster? Address TranslaMon University of Washington Speeding up TranslaMon with a TLB ¢  SoluMon: add another cache! ¢  TranslaKon Lookaside Buffer (TLB): §  Small hardware cache in MMU §  Maps virtual page numbers to physical page numbers §  Contains complete page table entries for small number of pages §  Modern Intel processors: 128 or 256 entries in TLB Address TranslaMon University of Washington TLB Hit CPU Chip TLB 2 VPN CPU PTE 3 1 VA MMU Data 5 A TLB hit eliminates a memory access Address TranslaMon PA 4 Cache/ Memory University of Washington TLB Miss CPU Chip TLB 2 4 PTE VPN CPU 1 VA MMU 3 PTEA PA Cache/ Memory 5 Data 6 A TLB miss incurs an addiMonal memory access (the PTE) Fortunately, TLB misses are rare Address TranslaMon University of Washington Virtual Memory (VM) ¢  ¢  ¢  ¢  ¢  Overview and moMvaMon IndirecMon VM as a tool for caching Memory management/protecMon and address translaMon Virtual memory example Virtual Memory Example University of Washington Simple Memory System Example ¢  Addressing §  14-­‐bit virtual addresses §  12-­‐bit physical address §  Page size = 64 bytes 13 12 11 10 9 8 7 6 5 4 3 2 1 VPN VPO Virtual Page Number 0 Virtual Page Offset 11 10 9 8 7 6 5 4 3 2 1 PPN PPO Physical Page Number Physical Page Offset Virtual Memory Example 0 University of Washington Simple Memory System Page T...
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