Calculating cache global miss rate....

[fbrdphreak]

Anyone wanna give me the 411 on calculating cache global miss rate? All I can find is something that says "#L2 misses / # of ref's made by processor"

But then isn't that the same as local cache miss rate for the L2 cache? Local cache miss rate --> "# misses experienced by cache / # of incoming references"

😕

HLPLZ! thanks

 

[Reel]

global cache miss rate = 1 - global cache hit rate

 

[fbrdphreak]

I need to be able to calculate it from memory references made by a computer running a certain program & number of L1 or L2 cache misses.

 

[Reel]

If it misses L1 then it can look in L2. If it misses L2 AND L1 (which is essentially a miss in L2 since it looks in L1 first), then it would be a global cache miss. So every time that happens summed and then divided by the total number of cache accesses should yield the global cache miss rate.

 

[fbrdphreak]

Makes sense. So essential local miss rate for L2 is the same as global miss rate then. I figured it was something like that, I just couldn't find anything that spelled it out like that. Thanks!

 

[mugs]

You'll get better help if you post in the right forum.

 

[Reel]

I'd suggest verifying it with someone else in the class since you aren't getting a second opinion from ATOT. I hated that part of my education but it seems logical to me.

 

[mugs]

Originally posted by: fbrdphreak
Makes sense. So essential local miss rate for L2 is the same as global miss rate then. I figured it was something like that, I just couldn't find anything that spelled it out like that. Thanks!

No, because if you get a hit in the L1 cache you don't need to go to the L2 cache.

 

[fbrdphreak]

So if global miss rate is the number of L2 cache misses divided by the memory references, is the local miss rate for L2 then (#L1 misses + #L2 misses) / (mem references) ?