The Improvement of LRU Liao Yansong

The Weakness of LRU “Only Time, No Frequency”

Oracle Present a New One

Crate a LRU List

‘V’ Replace ‘U’

‘V’ ‘L’

Set a Mark for each Block

When the value of last Mark is greater than two

‘S’ ‘A’

Insert a New ‘Y’

If ‘Y’ is Visited again

‘Y’ Won’t Be Put in Hot Edge until …… Decrease Operation Times

But Another Question Arises…… Dirty Block

Dirty Block Won’t Be Wrote Back until…… Decrease Operation Times

But If Dirty Blocks Are Too More, the Cost of Finding a Clean Block Is Too High

Create a Dirty LRU List

Of Course, the Size of Dirty LRU List is Limited When It Reaches 40% of the Whole Cache, DBWn Will Refresh It

The Improvement of LRU “Both Time And Frequency”

Thanks~