Feature Request: Get loaded cache lines about pycachesim

[JanLJL]

Hi @stettberger,

sorry for the delayed reply!
I am not sure if my suggested solution fully meets your requirements, but maybe it is a first step in the right direction.

The cleanest way would be check against cache.backend.cached for a specific cache if a cache line ID is in the cache, but due to the fact this is a set and quite expensive in terms of computation, I would recommend introducing another dictionary data structure like this:

from cachesim import CacheSimulator, Cache, MainMemory
import collections
import itertools


def load_and_track_cl(CacheSimulator: cs, addr, length):
    cl_ids = set()
    # make sure to have one address per CL in case length > cl_size
    addresses = itertools.chain(range(addr, addr+length, cs.last_level.backend.cl_size), [addr+length-1])
    for ad in addresses:
        cl_id = ad >> cs.last_level.backend.cl_bits
        if cl_id not in cs.cache_dict:
            cl_ids.add(cl_id)
            cs.cache_dict[cl_id] = True
    # do actual load
    cs.load(addr, length)
    return cl_ids


mem = MainMemory()
l1 = Cache("L1", 128, 4, 32, "LRU")
mem.load_to(l1)
mem.store_from(l1)
cs = CacheSimulator(l1, mem)
# create additional data structure in CacheSimulator
cs.cache_dict = collections.OrderedDict()

print("Loaded CL_ids: {}".format(load_and_track_cl(cs, 16, 4)))
print("Loaded CL_ids: {}".format(load_and_track_cl(cs, 20, 4)))
print("Loaded CL_ids: {}".format(load_and_track_cl(cs, 32, 4)))
print("Loaded CL_ids: {}".format(load_and_track_cl(cs, 127, 4)))
print("Loaded CL_ids: {}".format(load_and_track_cl(cs, 192, 80)))

Result:

Loaded CL_ids: {0}
Loaded CL_ids: set()
Loaded CL_ids: {1}
Loaded CL_ids: {3, 4}
Loaded CL_ids: {8, 6, 7}

I checked this against your code snippet and validated it with a few hundred thousands randomly generated memory addresses and timed it, which gave me an approx. speedup of 3x.
Please keep in mind that there are cases in which this doesn't work , for example, if you have a victim cache.
I hope this helps nonetheless!

[JanLJL]

Closing this issue for now, but I am happy to further discuss the topic!
Therefore, feel free to reopen.