“Prefetching” is a technique that leverages predictable address patterns to speculatively bring in additional cache blocks when a particular cache block is accessed. One example of prefetching is a stream buff er that prefetches sequentially adjacent cache blocks into a separate buff er when a particular cache block is brought in. If the data is found in the prefetch buff er, it is considered as a hit and moved into the cache and the next cache block is prefetched. Assume a two-entry stream buff er and assume that the cache latency is such that a cache block can be loaded before the computation on the previous cache block is completed. What is the miss rate for the address stream above?Cache block size (B) can aff ect both miss rate and miss latency. Assuming a 1-CPI machine with an average of 1.35 references (both instruction and data) per instruction, help find the optimal block size given the following miss rates for various block sizes. 8: 4% 16: 3% 32: 2% 64: 1.5% 128: 1% What is the optimal block size for a miss latency of 20×B cycles?What is the optimal block size for a miss latency of 24+B cycles?For constant miss latency, what is the optimal block size?
“Prefetching” is a technique that leverages predictable address patterns to speculatively bring in additional cache blocks when a particular cache block is accessed. One example of prefetching is a stream buff er that prefetches sequentially adjacent cache blocks into a separate buff er when a particular cache block is brought in. If the data is found in the prefetch buff er, it is considered as a hit and moved into the cache and the next cache block is prefetched. Assume a two-entry stream buff er and assume that the cache latency is such that a cache block can be loaded before the computation on the previous cache block is completed. What is the miss rate for the address stream above?
Cache block size (B) can aff ect both miss rate and miss latency. Assuming a 1-CPI machine with an average of 1.35 references (both instruction and data) per instruction, help find the optimal block size given the following miss rates for various block sizes.
| 8: 4% | 16: 3% | 32: 2% | 64: 1.5% | 128: 1% |
What is the optimal block size for a miss latency of 20×B cycles?
What is the optimal block size for a miss latency of 24+B cycles?
For constant miss latency, what is the optimal block size?
To improve the system performance prefetching technique is used. In this technique, the required data is stored in the buffer memory so that when the processor needs that data it can be processed speedily. It is used to speed up the data fetching process. A miss rate is the ratio of the total number of miss caches and the number of requests made by memory.
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