One of things we miss in gem5 is the capability to neatly compose the
cache hierarchy of CPUs and clusters of CPUs. The BaseCPU
addPrivateSplitL1Caches and addTwoLevelCacheHierarchy APIs have
historically been used to bind cache levels together.
These APIs have been superseeded by the introduction of the Cache
hierarchy abstraction in the standard library. The standard library
makes it cleaner for a user to quickly instantiate a hierarchy of caches
with few lines of code. While this removes a lot of complexity for a
user, the Hierarchy objects still have little information about their
internal topology.
To address this problem, this patch adds a tree data structure to the
AbstractCacheHierarchy class, where every node of the tree represent
a cache in the hierarchy. In this way we will expose APIs for traversing
and querying the tree.
For example a 2 CPUs system with private L1, private L2 and shared L3
will contain the following tree:
[root]
|
[L3]
/\
/ \
[L2] [L2]
| |
[L1] [L1]
Change-Id: I78fe6ad094f0938ff9bed191fb10b9e841418692
Signed-off-by: Giacomo Travaglini <giacomo.travaglini@arm.com>
d67672facc