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cpu-o3: remove false dummy entry in LSQ

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The constructor of the LoadQueue and StoreQueue were adding
an additional entry compared to the given configuration.

The removed comment was saying that this additional entry was
used as a dummy entry.
This is not necessary anymore with the current structure.
It was even leading to incorrect behavior as a loadQueue
could have one more outstanding load than specified
by the configuration.

Valgrind does not spot any illegal access.

Change-Id: I41507d003e4d55e91215e21f57119af7b3e4d465
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/50732
Reviewed-by: Bobby R. Bruce <bbruce@ucdavis.edu>
Maintainer: Bobby R. Bruce <bbruce@ucdavis.edu>
Tested-by: kokoro <noreply+kokoro@google.com>
This commit is contained in:
Tom Rollet
2021-09-09 15:09:20 +02:00
parent 43b8a93748
commit f61818b370
1 changed files with 3 additions and 7 deletions
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10
src/cpu/o3/lsq_unit.cc
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@@ -200,7 +200,7 @@ LSQUnit::completeDataAccess(PacketPtr pkt)
}
LSQUnit::LSQUnit(uint32_t lqEntries, uint32_t sqEntries)
: lsqID(-1), storeQueue(sqEntries+1), loadQueue(lqEntries+1),
: lsqID(-1), storeQueue(sqEntries), loadQueue(lqEntries),
storesToWB(0),
htmStarts(0), htmStops(0),
lastRetiredHtmUid(0),
@@ -417,20 +417,16 @@ LSQUnit::getMemDepViolator()
unsigned
LSQUnit::numFreeLoadEntries()
{
//LQ has an extra dummy entry to differentiate
//empty/full conditions. Subtract 1 from the free entries.
DPRINTF(LSQUnit, "LQ size: %d, #loads occupied: %d\n",
1 + loadQueue.capacity(), loadQueue.size());
loadQueue.capacity(), loadQueue.size());
return loadQueue.capacity() - loadQueue.size();
}
unsigned
LSQUnit::numFreeStoreEntries()
{
//SQ has an extra dummy entry to differentiate
//empty/full conditions. Subtract 1 from the free entries.
DPRINTF(LSQUnit, "SQ size: %d, #stores occupied: %d\n",
1 + storeQueue.capacity(), storeQueue.size());
storeQueue.capacity(), storeQueue.size());
return storeQueue.capacity() - storeQueue.size();
}