Macro/Micro architectural imporvements of K8L(K10) over K8
Quad-core
- Native quad-core design
- Redesigned and improved crossbar(northbridge)
- Improved power management
- New level of cache added, L3 VICTIM
Power management - DICE(Dynamic Independent Core Engagement)
- Supports separate CPU core and memory controller power planes to allow CPU to lower its power state while the memory controller is running full bore
- Enhanced AMD's PowerNow allows individual core frequencies to lower while other cores may be running full bore
Virtualization improvements
- Nested Paging(NP):
* Guest and Host page tables both exist in memory.(The CPU walks both page tables)
* Nested walk can have up to 24 memory acesses! (Hardware caching accelerates the walk)
* "Wire-to-wire" translations are cached in TLBs
* NP eliminates Hypervisor cycles spent managing shadow pages(As much as 75% Hypervisor time)
- Reduced world-switch time by 25%:
* World-switch time: round-trup to Hypervisor and back
Dedicated L1 cache
- 256bit 64kB (32kB instruction/32kB data)
- 2 x 128bit loads/cycle
- lowest latency
Dedicated L2 cache
- 128bit 512kB
- 128bit bus to northbridge
- reduced latency
- eliminates conflicts common in shared caches - better for virtualization
Shared L3 cache
- 128bit 2MB
- Victim-cache architecture maximizes efficiency of cache hierarchy
- Fills from L3 leave likely shared lines in the L3
- Sharing-aware replacement policy
- Expandable
Independent DRAM controllers
- Concurrency
- More DRAM banks reduces page conflicts
- Longer burst length improves command efficiency
- Dual channel unbuffered 1066 support(applies to socket AM2+ and s1207+ QFX only)
- Channel Interleaving
Optimized DRAM paging
- Increase page hits
- Decrease page conflicts
Re-architect northbridge for higher bandwidth
- Increase buffer sizes
- Optimize schedulers
- Ready to support future DRAM technologies
Write bursting
- Minimize Rd/Wr Turnaround
DRAM prefetcher
- Track positive and negative, unit and non-unit strides
- Dedicated buffer for prefetched data
- Aggressively fill idle DRAM cycles
Core prefetchers
- DC Prefetcher fills directly to L1 Cache
- IC Prefetcher more flexible
* 2 outstanding requests to any address
HyperTransport 3
- up to four 16bit cHT links
- up to 5200MT/s per link
- un-ganging mode: each 16bit HT link can be divided in two 8bit virutal links
CPU Core IPC Enhancements:
Advanced branch prediction
- Dedicated 512-entry Indirect Predictor
- Double return stacksize
- More branch history bits and improved branch hashing
History-based pattern predictor
32B instruction fetch
- Benefits integer code too
- Reduced split-fetch instruction cases
Sideband Stack Optimizer
- Perform stack adjustments for PUSH/POP operations “on the side”
- Stack adjustments don’t occupy functional unit bandwidth
- Breaks serial dependence chains for consecutive PUSH/POPs
Out-of-order load execution
- New technology allows load instructions to bypass:
* Other loads
* Other stores which are known not to alias with the load
- Significantly mitigates L2 cache latency
TLB Optimisations
- Support for 1G pages
- 48bit physical address (256TB)
- Larger TLBs key for:
* Virtualized workloads
* Large-footprint databases and
* transaction processing
- DTLB:
* Fully-associative 48-way TLB (4K, 2M, 1G)
* Backed by L2 TLBs: 512 x 4K, 128 x 2M
- ITLB:
* 16 x 2M entries
Data-dependent divide latency
Additional fastpath instructions
– CALL and RET-Imm instructions
– Data movement between FP & INT
Bit Manipulation extensions
- LZCNT/POPCNT
SSE extensions
- EXTRQ/INSERTQ (SSE4A)
- MOVNTSD/MOVNTSS (SSE4A)
- MWAIT/MONITOR (SSE3)
Comprehensive Upgrades for SSE
- Dual 128-bit SSE dataflow
- Up to 4 dual precision FP OPS/cycle
- Dual 128-bit loads per cycle
- New vector code, SSE128
- Can perform SSE MOVs in the FP “store” pipe
- Execute two generic SSE ops + SSE MOV each cycle (+ two 128-bit SSE loads)
- FP Scheduler can hold 36 Dedicated x 128-bit ops
- SSE Unaligned Load-Execute mode:
* Remove alignment requirements for SSE ld-op instructions
* Eliminate awkward pairs of separate load and compute instructions
* To improve instruction packing and decoding efficiency
K8L(K10) large die Shot
Source: AMD slides, and other sources from Internet
P.S. Any additional data or informations will be highly appreciated
