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Matth · 06-04-2005, 17:55

A loop that is a few bytes smaller than the cache will execute at cache speed.

A loop that is a few bytes larger than the cache, may end up executing entirely at main RAM speed, as both the common rules ... LRU and LFU will both let what's most needed slip away.

Actually, another rule for cache line discarding would work better - RANDOM.

The other problem with caches - their own speed (in the shape of increased latency) tends to fall if the size of cache is increased wiithout improving the cache architecture.

I did learn about tags, dirty bits and all that.

06-04-2005, 17:55	#6
Matth Inactive Join Date: Mar 2004 Services: BB:M, TV:XL, Phone:M, Loyalty Posts: 2,516	Re: L2 cache question A loop that is a few bytes smaller than the cache will execute at cache speed. A loop that is a few bytes larger than the cache, may end up executing entirely at main RAM speed, as both the common rules ... LRU and LFU will both let what's most needed slip away. Actually, another rule for cache line discarding would work better - RANDOM. The other problem with caches - their own speed (in the shape of increased latency) tends to fall if the size of cache is increased wiithout improving the cache architecture. I did learn about tags, dirty bits and all that.