L1 cache vs l2 cache

[mananap2010]

Hello,
what is the function of l1 & l2 cache memory?

 

[Timop]

Its a fast small storage for data used by the CPU.

L1 is usually used as a storage for decoded instructions, while L2 is a general cache for a single core.

Even-though you haven't mentioned it, There's also a higher level of cached called L3 cache which is a general cache for the whole chip.

 

[MarkG]

L1 is usually used as a storage for decoded instructions, while L2 is a general cache for a single core.

And L2 is usually much larger and much slower than L1, though still much faster than going out to RAM .

 

[rohn_avni]

And L2 is usually much larger and much slower than L1, though still much faster than going out to RAM .

cache memory is the fastest memory in the whole setup......

 

[Guest]

cache memory is the fastest memory in the whole setup......

I'm seeing chip block diagrams showing "internal" L2 cache. ie. The ARM processor in the Droid. I thought L1 was internal and L2 external (expandable.) EC

 

[Emperus]

A processor cache memory is not user expandable.. Refer to wikipedia or google it to know more about cache memory.. Give a read here too-

http://www.wisegeek.com/what-is-cache-memory.htm

 

[gamerk316]

As a rule, the CPU cache is basically REALLY fast access high speed memory. Each level is slightly larger then the last, but also slightly slower. In a multiple-core environment, one or multiple levels of cache may be dedicated to either a specific core, or for the entire CPU as a whole.

As a general rule:
L1 Cache: 2-3 clcok cycle access
L2 Cache: ~10 clockcycle access
L3 Cache: ~20-30 clockcycle access
Main Memory: ~100 clock cycle access; > 100,000 cycle access if a new page must be loaded. (Hence why more RAM increases speed: Fewer page faults).