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Which cache replacement algorithm is better?
Optimal Replacement: The best algorithm is called Bélády’s algorithm because it’ll always discard an item from the cache if it is no longer needed in future. Of course this is theoretical and can’t be implemented in real-life since it is generally impossible to predict how far in the future information will be needed.
Why do we need a cache replacement policy?
In computing, cache algorithms (also frequently called cache replacement algorithms or cache replacement policies) are optimizing instructions, or algorithms, that a computer program or a hardware-maintained structure can utilize in order to manage a cache of information stored on the computer.
What is a FIFO algorithm?
First In First Out (FIFO) – This is the simplest page replacement algorithm. In this algorithm, the operating system keeps track of all pages in the memory in a queue, the oldest page is in the front of the queue. When a page needs to be replaced page in the front of the queue is selected for removal.
Does FIFO approximate LRU?
Hit Rate Comparison. FIFO attempts to approximate LRU behavior and the simulation results show that it is doing so relatively well.
Why is LRU better than FIFO in Stack Overflow?
Treat the RAM as a cache. In order to be an effective cache, it needs to keep the items most likely to be requested in memory. LRU keeps the things that were most recently used in memory. FIFO keeps the things that were most recently added.
Which is better FIFO or unknown code Random?
Unknown code RANDOM is better for 4 way or above. If it’s single function or you want the most speed from something your willing to optimise, and or you don’t care about worst case, then LRU is probably what you want. If you have very few way’s LRU is likely what you want unless you have a very specific scenario then FIFO might be OK.
Which is worse a random policy or a LRU policy?
A random replacement policy would on random cause a worst case hit every 1024 replacements (ie. 99.9% hit), in either LRU or FIFO I could always write a programme which would “thrash” ie. always cause a worst case behavouir (ie. 0% hit).
Which is better, unknown code random or LRU?
Consider if writethrough might be better than writeback. Unknown code RANDOM is better for 4 way or above. If it’s single function or you want the most speed from something your willing to optimise, and or you don’t care about worst case, then LRU is probably what you want.