From d207e9ccee411877fdeac80bb68a27900560f50f Mon Sep 17 00:00:00 2001 From: "Daniel R. Carvalho" Date: Mon, 19 Feb 2018 15:13:11 +0100 Subject: mem-cache: Split array indexing and replacement policies. Replacement policies (LRU, Random) are currently considered as array indexing methods, but have completely different functionalities: - Array indexers determine the possible locations for block allocation. This information is used to generate replacement candidates when conflicts happen. - Replacement policies determine which of the replacement candidates should be evicted to make room for new allocations. For this reason, they were split into different classes. Advantages: - Easier and more straightforward to implement other replacement policies (RRIP, LFU, ARC, ...) - Allow easier future implementation of cache organization schemes As now we can't assure the use of sets, the previous way to create a true LRU is not viable. Now a timestamp_bits parameter controls how many bits are dedicated for the timestamp, and a true LRU can be achieved through an infinite number of bits (although a few bits suffice in practice). Change-Id: I23750db121f1474d17831137e6ff618beb2b3eda Reviewed-on: https://gem5-review.googlesource.com/8501 Reviewed-by: Nikos Nikoleris Reviewed-by: Jason Lowe-Power Maintainer: Nikos Nikoleris --- src/mem/cache/Cache.py | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) (limited to 'src/mem/cache/Cache.py') diff --git a/src/mem/cache/Cache.py b/src/mem/cache/Cache.py index bac6c73e1..faee0925b 100644 --- a/src/mem/cache/Cache.py +++ b/src/mem/cache/Cache.py @@ -43,6 +43,7 @@ from m5.params import * from m5.proxy import * from MemObject import MemObject from Prefetcher import BasePrefetcher +from ReplacementPolicies import * from Tags import * class BaseCache(MemObject): @@ -74,7 +75,10 @@ class BaseCache(MemObject): prefetch_on_access = Param.Bool(False, "Notify the hardware prefetcher on every access (not just misses)") - tags = Param.BaseTags(LRU(), "Tag store (replacement policy)") + tags = Param.BaseTags(BaseSetAssoc(), "Tag store") + replacement_policy = Param.BaseReplacementPolicy(LRURP(), + "Replacement policy") + sequential_access = Param.Bool(False, "Whether to access tags and data sequentially") -- cgit v1.2.3