Caching Hit&;未命中使用4路关联缓存
问题:Caching Hit&;未命中使用4路关联缓存,caching,memory-management,Caching,Memory Management,问题: Given a computer ,where were made the following memory accesses (from left to right) : 5 ,10 ,2 ,34 ,18 ,4 ,22 ,21 ,11 ,2 * Decide if we have a HIT or MISS when dealing with a 4-way associative mapping , when the total size of the cache is
Given a computer ,where were made the following memory accesses
(from left to right) :
5 ,10 ,2 ,34 ,18 ,4 ,22 ,21 ,11 ,2
* Decide if we have a HIT or MISS when dealing with a 4-way associative mapping ,
when the total size of the cache is 32 blocks of 2 bytes !
* When you're done , write the final map of the cache
我的答覆是:
集合的大小为4,因此:
(区块数量)/(通道数量)=32/4=8
然后我们有一个缓存,它有八个单元格,从0到7(如果我错了,请纠正我!!?)
现在:5:(4,5)→5/2=2→2 % 8=2→第2单元→错过
10:(10,11)→10/2=5→5 % 8=5→第5单元→错过
2:(2,3)→2/2=1→1 %8=1→第1单元→错过
34:(34,35)→34/2=17→17 % 8=1→第1单元→错过
18:(18,19)→18/2=9→9 % 8=1→第1单元→错过
4:在第二单元中击中
22:(22,23)→22/2=11→11 % 8=3→第三单元→错过
21:(20,21)→21/2=10→10 % 8=2→第2单元→错过
11:在第5单元中击中
2:在第1单元中击中
现在,缓存的最终映射是:
0: empty
1: (2,3) (34,35) (18,19)
2: (4,5) (20,21)
3: (22,23)
4: empty
5: (10,11)
6: empty
7: empty
from collections import defaultdict
d = defaultdict(list)
for item in (5 ,10 ,2 ,34 ,18 ,4 ,22 ,21 ,11 ,2):
value = item // 2 * 2, item // 2 * 2 + 1
cell = item // 2 % 8
if value in d[cell]:
print "HIT", cell
else:
d[cell].append(value)
print "MISS", cell
for i in range(8):
print i, d[i]
--
MISS 2
MISS 5
MISS 1
MISS 1
MISS 1
HIT 2
MISS 3
MISS 2
HIT 5
HIT 1
0 []
1 [(2, 3), (34, 35), (18, 19)]
2 [(4, 5), (20, 21)]
3 [(22, 23)]
4 []
5 [(10, 11)]
6 []
7 []