diff options
Diffstat (limited to 'src')
-rw-r--r-- | src/mem/simple_dram.cc | 96 | ||||
-rw-r--r-- | src/mem/simple_dram.hh | 6 |
2 files changed, 48 insertions, 54 deletions
diff --git a/src/mem/simple_dram.cc b/src/mem/simple_dram.cc index 69209fb8a..46e81f564 100644 --- a/src/mem/simple_dram.cc +++ b/src/mem/simple_dram.cc @@ -791,34 +791,7 @@ SimpleDRAM::chooseNextWrite() if (memSchedPolicy == Enums::fcfs) { // Do nothing, since the correct request is already head } else if (memSchedPolicy == Enums::frfcfs) { - // Only determine bank availability when needed - uint64_t earliest_banks = 0; - - auto i = writeQueue.begin(); - bool foundRowHit = false; - while (!foundRowHit && i != writeQueue.end()) { - DRAMPacket* dram_pkt = *i; - const Bank& bank = dram_pkt->bankRef; - if (bank.openRow == dram_pkt->row) { - DPRINTF(DRAM, "Write row buffer hit\n"); - writeQueue.erase(i); - writeQueue.push_front(dram_pkt); - foundRowHit = true; - } else { - // No row hit, go for first ready - if (earliest_banks == 0) - earliest_banks = minBankFreeAt(writeQueue); - - // Bank is ready or is one of the first available bank - if (bank.freeAt <= curTick() || - bits(earliest_banks, dram_pkt->bankId, dram_pkt->bankId)) { - writeQueue.erase(i); - writeQueue.push_front(dram_pkt); - break; - } - } - ++i; - } + reorderQueue(writeQueue); } else panic("No scheduling policy chosen\n"); @@ -845,32 +818,7 @@ SimpleDRAM::chooseNextRead() // Do nothing, since the request to serve is already the first // one in the read queue } else if (memSchedPolicy == Enums::frfcfs) { - // Only determine this when needed - uint64_t earliest_banks = 0; - - for (auto i = readQueue.begin(); i != readQueue.end() ; ++i) { - DRAMPacket* dram_pkt = *i; - const Bank& bank = dram_pkt->bankRef; - // Check if it is a row hit - if (bank.openRow == dram_pkt->row) { - DPRINTF(DRAM, "Row buffer hit\n"); - readQueue.erase(i); - readQueue.push_front(dram_pkt); - break; - } else { - // No row hit, go for first ready - if (earliest_banks == 0) - earliest_banks = minBankFreeAt(readQueue); - - // Bank is ready or is the first available bank - if (bank.freeAt <= curTick() || - bits(earliest_banks, dram_pkt->bankId, dram_pkt->bankId)) { - readQueue.erase(i); - readQueue.push_front(dram_pkt); - break; - } - } - } + reorderQueue(readQueue); } else panic("No scheduling policy chosen!\n"); @@ -879,6 +827,46 @@ SimpleDRAM::chooseNextRead() } void +SimpleDRAM::reorderQueue(std::deque<DRAMPacket*>& queue) +{ + // Only determine this when needed + uint64_t earliest_banks = 0; + + // Search for row hits first, if no row hit is found then schedule the + // packet to one of the earliest banks available + bool found_earliest_pkt = false; + auto selected_pkt_it = queue.begin(); + + for (auto i = queue.begin(); i != queue.end() ; ++i) { + DRAMPacket* dram_pkt = *i; + const Bank& bank = dram_pkt->bankRef; + // Check if it is a row hit + if (bank.openRow == dram_pkt->row) { + DPRINTF(DRAM, "Row buffer hit\n"); + selected_pkt_it = i; + break; + } else if (!found_earliest_pkt) { + // No row hit, go for first ready + if (earliest_banks == 0) + earliest_banks = minBankFreeAt(queue); + + // Bank is ready or is the first available bank + if (bank.freeAt <= curTick() || + bits(earliest_banks, dram_pkt->bankId, dram_pkt->bankId)) { + // Remember the packet to be scheduled to one of the earliest + // banks available + selected_pkt_it = i; + found_earliest_pkt = true; + } + } + } + + DRAMPacket* selected_pkt = *selected_pkt_it; + queue.erase(selected_pkt_it); + queue.push_front(selected_pkt); +} + +void SimpleDRAM::accessAndRespond(PacketPtr pkt, Tick static_latency) { DPRINTF(DRAM, "Responding to Address %lld.. ",pkt->getAddr()); diff --git a/src/mem/simple_dram.hh b/src/mem/simple_dram.hh index a7a100d7c..535e3a8c5 100644 --- a/src/mem/simple_dram.hh +++ b/src/mem/simple_dram.hh @@ -398,6 +398,12 @@ class SimpleDRAM : public AbstractMemory void chooseNextWrite(); /** + * For FR-FCFS policy reorder the read/write queue depending on row buffer + * hits and earliest banks available in DRAM + */ + void reorderQueue(std::deque<DRAMPacket*>& queue); + + /** * Looking at all banks, determine the moment in time when they * are all free. * |