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mem-cache: Use SatCounter for prefetchers

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Many prefetchers re-implement saturating counters with ints. Make
them use SatCounters instead.

Added missing operators and constructors to SatCounter for that to
be possible and their respective tests.

Change-Id: I36f10c89c27c9b3d1bf461e9ea546920f6ebb888
Signed-off-by: Daniel <odanrc@yahoo.com.br>
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/17995
Tested-by: kokoro <noreply+kokoro@google.com>
Reviewed-by: Javier Bueno Hedo <javier.bueno@metempsy.com>
Maintainer: Jason Lowe-Power <jason@lowepower.com>
This commit is contained in:
Daniel
2019-04-11 08:37:56 +02:00
committed by Daniel Carvalho
parent 50a533f101
commit c1bd27907d
10 changed files with 76 additions and 91 deletions
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26
src/mem/cache/prefetch/irregular_stream_buffer.cc vendored
View File

@@ -36,7 +36,7 @@
IrregularStreamBufferPrefetcher::IrregularStreamBufferPrefetcher(
const IrregularStreamBufferPrefetcherParams *p)
: QueuedPrefetcher(p), maxCounterValue(p->max_counter_value),
: QueuedPrefetcher(p),
chunkSize(p->chunk_size),
prefetchCandidatesPerEntry(p->prefetch_candidates_per_entry),
degree(p->degree),
@@ -47,12 +47,14 @@ IrregularStreamBufferPrefetcher::IrregularStreamBufferPrefetcher(
p->address_map_cache_entries,
p->ps_address_map_cache_indexing_policy,
p->ps_address_map_cache_replacement_policy,
AddressMappingEntry(prefetchCandidatesPerEntry)),
AddressMappingEntry(prefetchCandidatesPerEntry,
p->num_counter_bits)),
spAddressMappingCache(p->address_map_cache_assoc,
p->address_map_cache_entries,
p->sp_address_map_cache_indexing_policy,
p->sp_address_map_cache_replacement_policy,
AddressMappingEntry(prefetchCandidatesPerEntry)),
AddressMappingEntry(prefetchCandidatesPerEntry,
p->num_counter_bits)),
structuralAddressCounter(0)
{
assert(isPowerOf2(prefetchCandidatesPerEntry));
@@ -100,30 +102,29 @@ IrregularStreamBufferPrefetcher::calculatePrefetch(const PrefetchInfo &pfi,
if (mapping_A.counter > 0 && mapping_B.counter > 0) {
// Entry for A and B
if (mapping_B.address == (mapping_A.address + 1)) {
if (mapping_B.counter < maxCounterValue) {
mapping_B.counter += 1;
}
mapping_B.counter++;
} else {
if (mapping_B.counter == 1) {
// counter would hit 0, reassign address
mapping_B.counter = 1;
// Counter would hit 0, reassign address while keeping
// counter at 1
mapping_B.address = mapping_A.address + 1;
addStructuralToPhysicalEntry(mapping_B.address, is_secure,
correlated_addr_B);
} else {
mapping_B.counter -= 1;
mapping_B.counter--;
}
}
} else {
if (mapping_A.counter == 0) {
// if A is not valid, generate a new structural address
mapping_A.counter = 1;
mapping_A.counter++;
mapping_A.address = structuralAddressCounter;
structuralAddressCounter += chunkSize;
addStructuralToPhysicalEntry(mapping_A.address,
is_secure, correlated_addr_A);
}
mapping_B.counter = 1;
mapping_B.counter.reset();
mapping_B.counter++;
mapping_B.address = mapping_A.address + 1;
// update SP-AMC
addStructuralToPhysicalEntry(mapping_B.address, is_secure,
@@ -203,7 +204,8 @@ IrregularStreamBufferPrefetcher::addStructuralToPhysicalEntry(
}
AddressMapping &mapping = sp_entry->mappings[map_index];
mapping.address = physical_address;
mapping.counter = 1;
mapping.counter.reset();
mapping.counter++;
}
IrregularStreamBufferPrefetcher*