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From CompArch

Contents 1 L1, L2, L3, ... Ln 2 $ notation 3 Intel's MLC, LLC notation 4 Andy Glew's inner/outer terminology 5 Split I & D

L1, L2, L3, ... Ln

L1, L2, L3, ... Ln

Ln

n-th level of a multilevel data structure. Often specifically an n-th level cache.

L0

0-th level of a multilevel data structure. Usually arises because you start with an L1 data structure, and then add a smaller, faster, cache level. E.g. L0$. Some people get quite irritated by this term, insisting on renumbering everything starting at L1. Myself, I'm used to starting counting from 0: I program in C and C++. :-)

L1

1st level of a multilevel data structure. Often specifically means an L1$.

L2

2nd level of a multilevel data structure. Often specifically means an L2$.

L3

3rd level of a multilevel data structure. Often specifically means an L3$.

$ notation

$

A cute symbol for cache, used in acronyms such as I$, D$, L1$, etc.

$$

A cute symbol for L2 cache.

$$$

A cute symbol for L3 cache.

L1$

1st level cache; often specifically an L1 data cache. To distinguish, see I1$ and D1$.

L2$

2nd level cache; usually a unified cache, although more and more there are L2 I$ and D$. See UL2, MLC.

L3$

3rd level cache; usually unified. See LLC.

L0$

0-th level of a multilevel cache hierarchy. Usually arises because you start with an L1 data structure, and then add a smaller, faster, cache level. E.g. Pentium 4. I try to use the term innermost cache when numbering gets awkward.

Intel's MLC, LLC notation

FLC, MLC, LLC

Respectively the first level cache, second level cache, and last level cache of a hierarchy.

FLC

First level cache. "FLC" is rarely used, since there are usually split L1 I$ and D$. The innermost cache.

MLC

Middle level cache. Usually an L2$.

LLC

Last level cache. Usually an L3$. The outermost cache.

Andy Glew's inner/outer terminology

innermost cache

The innermost cache, closest to the processor. See FLC, L1$.

outermost cache

The outermost cache, furthest away from the processor. See LLC.

inner cache

A cache closer to the processor than the point of reference; a relative term.

outer cache

A cache further from the processor than the point of reference; a relative term.

Split I & D

I$

Instruction cache.

I1$

1st level instruction cache.

I2$

2nd level instruction cache.

D$

Data cache. Emphasizes distinction from I$.

D1$

1st level data cache. Often called simply an L1$. Emphasizes distinction from I1$.

D2$

2nd level data cache.

UL1$

Unified L1$, used to emphasize that there is no I1$ or D1$.

UL2$

Unified L2$. Often called simply L2$.

UL1

UL1$, without the $.

UL2

UL2$, without the $.