diff options
author | Nuwan Jayasena <Nuwan.Jayasena@amd.com> | 2012-07-10 22:51:53 -0700 |
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committer | Nuwan Jayasena <Nuwan.Jayasena@amd.com> | 2012-07-10 22:51:53 -0700 |
commit | 1740c4c448a65dee8b27dcdcdccdc1a6e8b4d6b6 (patch) | |
tree | f804e0cbaae1e2bf7b0037e1b88851c2b64dfd60 /src/mem/ruby/system/MemoryControl.cc | |
parent | 4a52a6ea2d84933a1ac8418fe2ba9222832a690d (diff) | |
download | gem5-1740c4c448a65dee8b27dcdcdccdc1a6e8b4d6b6.tar.xz |
ruby: memory controllers now inherit from an abstract "MemoryControl" class
Diffstat (limited to 'src/mem/ruby/system/MemoryControl.cc')
-rw-r--r-- | src/mem/ruby/system/MemoryControl.cc | 641 |
1 files changed, 9 insertions, 632 deletions
diff --git a/src/mem/ruby/system/MemoryControl.cc b/src/mem/ruby/system/MemoryControl.cc index 4e5ebdbe9..cf6a618e0 100644 --- a/src/mem/ruby/system/MemoryControl.cc +++ b/src/mem/ruby/system/MemoryControl.cc @@ -1,5 +1,6 @@ /* * Copyright (c) 1999-2008 Mark D. Hill and David A. Wood + * Copyright (c) 2012 Advanced Micro Devices, Inc. * All rights reserved. * * Redistribution and use in source and binary forms, with or without @@ -26,86 +27,9 @@ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. */ -/* - * Description: This module simulates a basic DDR-style memory controller - * (and can easily be extended to do FB-DIMM as well). - * - * This module models a single channel, connected to any number of - * DIMMs with any number of ranks of DRAMs each. If you want multiple - * address/data channels, you need to instantiate multiple copies of - * this module. - * - * Each memory request is placed in a queue associated with a specific - * memory bank. This queue is of finite size; if the queue is full - * the request will back up in an (infinite) common queue and will - * effectively throttle the whole system. This sort of behavior is - * intended to be closer to real system behavior than if we had an - * infinite queue on each bank. If you want the latter, just make - * the bank queues unreasonably large. - * - * The head item on a bank queue is issued when all of the - * following are true: - * the bank is available - * the address path to the DIMM is available - * the data path to or from the DIMM is available - * - * Note that we are not concerned about fixed offsets in time. The bank - * will not be used at the same moment as the address path, but since - * there is no queue in the DIMM or the DRAM it will be used at a constant - * number of cycles later, so it is treated as if it is used at the same - * time. - * - * We are assuming closed bank policy; that is, we automatically close - * each bank after a single read or write. Adding an option for open - * bank policy is for future work. - * - * We are assuming "posted CAS"; that is, we send the READ or WRITE - * immediately after the ACTIVATE. This makes scheduling the address - * bus trivial; we always schedule a fixed set of cycles. For DDR-400, - * this is a set of two cycles; for some configurations such as - * DDR-800 the parameter tRRD forces this to be set to three cycles. - * - * We assume a four-bit-time transfer on the data wires. This is - * the minimum burst length for DDR-2. This would correspond - * to (for example) a memory where each DIMM is 72 bits wide - * and DIMMs are ganged in pairs to deliver 64 bytes at a shot. - * This gives us the same occupancy on the data wires as on the - * address wires (for the two-address-cycle case). - * - * The only non-trivial scheduling problem is the data wires. - * A write will use the wires earlier in the operation than a read - * will; typically one cycle earlier as seen at the DRAM, but earlier - * by a worst-case round-trip wire delay when seen at the memory controller. - * So, while reads from one rank can be scheduled back-to-back - * every two cycles, and writes (to any rank) scheduled every two cycles, - * when a read is followed by a write we need to insert a bubble. - * Furthermore, consecutive reads from two different ranks may need - * to insert a bubble due to skew between when one DRAM stops driving the - * wires and when the other one starts. (These bubbles are parameters.) - * - * This means that when some number of reads and writes are at the - * heads of their queues, reads could starve writes, and/or reads - * to the same rank could starve out other requests, since the others - * would never see the data bus ready. - * For this reason, we have implemented an anti-starvation feature. - * A group of requests is marked "old", and a counter is incremented - * each cycle as long as any request from that batch has not issued. - * if the counter reaches twice the bank busy time, we hold off any - * newer requests until all of the "old" requests have issued. - * - * We also model tFAW. This is an obscure DRAM parameter that says - * that no more than four activate requests can happen within a window - * of a certain size. For most configurations this does not come into play, - * or has very little effect, but it could be used to throttle the power - * consumption of the DRAM. In this implementation (unlike in a DRAM - * data sheet) TFAW is measured in memory bus cycles; i.e. if TFAW = 16 - * then no more than four activates may happen within any 16 cycle window. - * Refreshes are included in the activates. - * - */ - #include "base/cast.hh" #include "base/cprintf.hh" +#include "mem/ruby/common/Address.hh" #include "mem/ruby/common/Consumer.hh" #include "mem/ruby/common/Global.hh" #include "mem/ruby/network/Network.hh" @@ -113,564 +37,17 @@ #include "mem/ruby/slicc_interface/NetworkMessage.hh" #include "mem/ruby/slicc_interface/RubySlicc_ComponentMapping.hh" #include "mem/ruby/system/MemoryControl.hh" +#include "mem/ruby/system/RubyMemoryControl.hh" +#include "mem/ruby/system/System.hh" using namespace std; +MemoryControl::MemoryControl(const Params *p) : SimObject(p), m_event(this) {}; +MemoryControl::~MemoryControl() {}; -class Consumer; - -// Value to reset watchdog timer to. -// If we're idle for this many memory control cycles, -// shut down our clock (our rescheduling of ourselves). -// Refresh shuts down as well. -// When we restart, we'll be in a different phase -// with respect to ruby cycles, so this introduces -// a slight inaccuracy. But it is necessary or the -// ruby tester never terminates because the event -// queue is never empty. -#define IDLECOUNT_MAX_VALUE 1000 - -// Output operator definition - -ostream& -operator<<(ostream& out, const MemoryControl& obj) -{ - obj.print(out); - out << flush; - return out; -} - - -// **************************************************************** - -// CONSTRUCTOR -MemoryControl::MemoryControl(const Params *p) - : SimObject(p), m_event(this) -{ - m_mem_bus_cycle_multiplier = p->mem_bus_cycle_multiplier; - m_banks_per_rank = p->banks_per_rank; - m_ranks_per_dimm = p->ranks_per_dimm; - m_dimms_per_channel = p->dimms_per_channel; - m_bank_bit_0 = p->bank_bit_0; - m_rank_bit_0 = p->rank_bit_0; - m_dimm_bit_0 = p->dimm_bit_0; - m_bank_queue_size = p->bank_queue_size; - m_bank_busy_time = p->bank_busy_time; - m_rank_rank_delay = p->rank_rank_delay; - m_read_write_delay = p->read_write_delay; - m_basic_bus_busy_time = p->basic_bus_busy_time; - m_mem_ctl_latency = p->mem_ctl_latency; - m_refresh_period = p->refresh_period; - m_tFaw = p->tFaw; - m_mem_random_arbitrate = p->mem_random_arbitrate; - m_mem_fixed_delay = p->mem_fixed_delay; - - m_profiler_ptr = new MemCntrlProfiler(name(), - m_banks_per_rank, - m_ranks_per_dimm, - m_dimms_per_channel); -} - -void -MemoryControl::init() -{ - m_msg_counter = 0; - - assert(m_tFaw <= 62); // must fit in a uint64 shift register - - m_total_banks = m_banks_per_rank * m_ranks_per_dimm * m_dimms_per_channel; - m_total_ranks = m_ranks_per_dimm * m_dimms_per_channel; - m_refresh_period_system = m_refresh_period / m_total_banks; - - m_bankQueues = new list<MemoryNode> [m_total_banks]; - assert(m_bankQueues); - - m_bankBusyCounter = new int [m_total_banks]; - assert(m_bankBusyCounter); - - m_oldRequest = new int [m_total_banks]; - assert(m_oldRequest); - - for (int i = 0; i < m_total_banks; i++) { - m_bankBusyCounter[i] = 0; - m_oldRequest[i] = 0; - } - - m_busBusyCounter_Basic = 0; - m_busBusyCounter_Write = 0; - m_busBusyCounter_ReadNewRank = 0; - m_busBusy_WhichRank = 0; - - m_roundRobin = 0; - m_refresh_count = 1; - m_need_refresh = 0; - m_refresh_bank = 0; - m_idleCount = 0; - m_ageCounter = 0; - - // Each tfaw shift register keeps a moving bit pattern - // which shows when recent activates have occurred. - // m_tfaw_count keeps track of how many 1 bits are set - // in each shift register. When m_tfaw_count is >= 4, - // new activates are not allowed. - m_tfaw_shift = new uint64[m_total_ranks]; - m_tfaw_count = new int[m_total_ranks]; - for (int i = 0; i < m_total_ranks; i++) { - m_tfaw_shift[i] = 0; - m_tfaw_count[i] = 0; - } -} - -MemoryControl::~MemoryControl() -{ - delete [] m_bankQueues; - delete [] m_bankBusyCounter; - delete [] m_oldRequest; - delete m_profiler_ptr; -} - -// enqueue new request from directory -void -MemoryControl::enqueue(const MsgPtr& message, int latency) -{ - Time current_time = g_eventQueue_ptr->getTime(); - Time arrival_time = current_time + latency; - const MemoryMsg* memMess = safe_cast<const MemoryMsg*>(message.get()); - physical_address_t addr = memMess->getAddress().getAddress(); - MemoryRequestType type = memMess->getType(); - bool is_mem_read = (type == MemoryRequestType_MEMORY_READ); - MemoryNode thisReq(arrival_time, message, addr, is_mem_read, !is_mem_read); - enqueueMemRef(thisReq); -} - -// Alternate entry point used when we already have a MemoryNode -// structure built. -void -MemoryControl::enqueueMemRef(MemoryNode& memRef) -{ - m_msg_counter++; - memRef.m_msg_counter = m_msg_counter; - physical_address_t addr = memRef.m_addr; - int bank = getBank(addr); - - DPRINTF(RubyMemory, - "New memory request%7d: %#08x %c arrived at %10d bank = %3x sched %c\n", - m_msg_counter, addr, memRef.m_is_mem_read ? 'R':'W', - memRef.m_time * g_eventQueue_ptr->getClock(), - bank, m_event.scheduled() ? 'Y':'N'); - - m_profiler_ptr->profileMemReq(bank); - m_input_queue.push_back(memRef); - - if (!m_event.scheduled()) { - schedule(m_event, curTick() + 1); - } -} - -// dequeue, peek, and isReady are used to transfer completed requests -// back to the directory -void -MemoryControl::dequeue() -{ - assert(isReady()); - m_response_queue.pop_front(); -} - -const Message* -MemoryControl::peek() -{ - MemoryNode node = peekNode(); - Message* msg_ptr = node.m_msgptr.get(); - assert(msg_ptr != NULL); - return msg_ptr; -} - -MemoryNode -MemoryControl::peekNode() -{ - assert(isReady()); - MemoryNode req = m_response_queue.front(); - DPRINTF(RubyMemory, "Peek: memory request%7d: %#08x %c sched %c\n", - req.m_msg_counter, req.m_addr, req.m_is_mem_read ? 'R':'W', - m_event.scheduled() ? 'Y':'N'); - - return req; -} - -bool -MemoryControl::isReady() -{ - return ((!m_response_queue.empty()) && - (m_response_queue.front().m_time <= g_eventQueue_ptr->getTime())); -} - -void -MemoryControl::setConsumer(Consumer* consumer_ptr) -{ - m_consumer_ptr = consumer_ptr; -} - -void -MemoryControl::print(ostream& out) const -{ -} - -void -MemoryControl::printConfig(ostream& out) -{ - out << "Memory Control " << name() << ":" << endl; - out << " Ruby cycles per memory cycle: " << m_mem_bus_cycle_multiplier - << endl; - out << " Basic read latency: " << m_mem_ctl_latency << endl; - if (m_mem_fixed_delay) { - out << " Fixed Latency mode: Added cycles = " << m_mem_fixed_delay - << endl; - } else { - out << " Bank busy time: " << m_bank_busy_time << " memory cycles" - << endl; - out << " Memory channel busy time: " << m_basic_bus_busy_time << endl; - out << " Dead cycles between reads to different ranks: " - << m_rank_rank_delay << endl; - out << " Dead cycle between a read and a write: " - << m_read_write_delay << endl; - out << " tFaw (four-activate) window: " << m_tFaw << endl; - } - out << " Banks per rank: " << m_banks_per_rank << endl; - out << " Ranks per DIMM: " << m_ranks_per_dimm << endl; - out << " DIMMs per channel: " << m_dimms_per_channel << endl; - out << " LSB of bank field in address: " << m_bank_bit_0 << endl; - out << " LSB of rank field in address: " << m_rank_bit_0 << endl; - out << " LSB of DIMM field in address: " << m_dimm_bit_0 << endl; - out << " Max size of each bank queue: " << m_bank_queue_size << endl; - out << " Refresh period (within one bank): " << m_refresh_period << endl; - out << " Arbitration randomness: " << m_mem_random_arbitrate << endl; -} - -void -MemoryControl::clearStats() const -{ - m_profiler_ptr->clearStats(); -} - -void -MemoryControl::printStats(ostream& out) const -{ - m_profiler_ptr->printStats(out); -} - -// Queue up a completed request to send back to directory -void -MemoryControl::enqueueToDirectory(MemoryNode req, int latency) -{ - Time arrival_time = g_eventQueue_ptr->getTime() - + (latency * m_mem_bus_cycle_multiplier); - req.m_time = arrival_time; - m_response_queue.push_back(req); - - DPRINTF(RubyMemory, "Enqueueing msg %#08x %c back to directory at %15d\n", - req.m_addr, req.m_is_mem_read ? 'R':'W', - arrival_time * g_eventQueue_ptr->getClock()); - - // schedule the wake up - g_eventQueue_ptr->scheduleEventAbsolute(m_consumer_ptr, arrival_time); -} - -// getBank returns an integer that is unique for each -// bank across this memory controller. -int -MemoryControl::getBank(physical_address_t addr) -{ - int dimm = (addr >> m_dimm_bit_0) & (m_dimms_per_channel - 1); - int rank = (addr >> m_rank_bit_0) & (m_ranks_per_dimm - 1); - int bank = (addr >> m_bank_bit_0) & (m_banks_per_rank - 1); - return (dimm * m_ranks_per_dimm * m_banks_per_rank) - + (rank * m_banks_per_rank) - + bank; -} - -// getRank returns an integer that is unique for each rank -// and independent of individual bank. -int -MemoryControl::getRank(int bank) -{ - int rank = (bank / m_banks_per_rank); - assert (rank < (m_ranks_per_dimm * m_dimms_per_channel)); - return rank; -} - -// queueReady determines if the head item in a bank queue -// can be issued this cycle -bool -MemoryControl::queueReady(int bank) -{ - if ((m_bankBusyCounter[bank] > 0) && !m_mem_fixed_delay) { - m_profiler_ptr->profileMemBankBusy(); - - DPRINTF(RubyMemory, "bank %x busy %d\n", bank, m_bankBusyCounter[bank]); - return false; - } - - if (m_mem_random_arbitrate >= 2) { - if ((random() % 100) < m_mem_random_arbitrate) { - m_profiler_ptr->profileMemRandBusy(); - return false; - } - } - - if (m_mem_fixed_delay) - return true; - - if ((m_ageCounter > (2 * m_bank_busy_time)) && !m_oldRequest[bank]) { - m_profiler_ptr->profileMemNotOld(); - return false; - } - - if (m_busBusyCounter_Basic == m_basic_bus_busy_time) { - // Another bank must have issued this same cycle. For - // profiling, we count this as an arb wait rather than a bus - // wait. This is a little inaccurate since it MIGHT have also - // been blocked waiting for a read-write or a read-read - // instead, but it's pretty close. - m_profiler_ptr->profileMemArbWait(1); - return false; - } - - if (m_busBusyCounter_Basic > 0) { - m_profiler_ptr->profileMemBusBusy(); - return false; - } - - int rank = getRank(bank); - if (m_tfaw_count[rank] >= ACTIVATE_PER_TFAW) { - m_profiler_ptr->profileMemTfawBusy(); - return false; - } - - bool write = !m_bankQueues[bank].front().m_is_mem_read; - if (write && (m_busBusyCounter_Write > 0)) { - m_profiler_ptr->profileMemReadWriteBusy(); - return false; - } - - if (!write && (rank != m_busBusy_WhichRank) - && (m_busBusyCounter_ReadNewRank > 0)) { - m_profiler_ptr->profileMemDataBusBusy(); - return false; - } - - return true; -} - -// issueRefresh checks to see if this bank has a refresh scheduled -// and, if so, does the refresh and returns true -bool -MemoryControl::issueRefresh(int bank) -{ - if (!m_need_refresh || (m_refresh_bank != bank)) - return false; - if (m_bankBusyCounter[bank] > 0) - return false; - // Note that m_busBusyCounter will prevent multiple issues during - // the same cycle, as well as on different but close cycles: - if (m_busBusyCounter_Basic > 0) - return false; - int rank = getRank(bank); - if (m_tfaw_count[rank] >= ACTIVATE_PER_TFAW) - return false; - - // Issue it: - DPRINTF(RubyMemory, "Refresh bank %3x\n", bank); - - m_profiler_ptr->profileMemRefresh(); - m_need_refresh--; - m_refresh_bank++; - if (m_refresh_bank >= m_total_banks) - m_refresh_bank = 0; - m_bankBusyCounter[bank] = m_bank_busy_time; - m_busBusyCounter_Basic = m_basic_bus_busy_time; - m_busBusyCounter_Write = m_basic_bus_busy_time; - m_busBusyCounter_ReadNewRank = m_basic_bus_busy_time; - markTfaw(rank); - return true; -} - -// Mark the activate in the tFaw shift register -void -MemoryControl::markTfaw(int rank) -{ - if (m_tFaw) { - m_tfaw_shift[rank] |= (1 << (m_tFaw-1)); - m_tfaw_count[rank]++; - } -} - -// Issue a memory request: Activate the bank, reserve the address and -// data buses, and queue the request for return to the requesting -// processor after a fixed latency. -void -MemoryControl::issueRequest(int bank) -{ - int rank = getRank(bank); - MemoryNode req = m_bankQueues[bank].front(); - m_bankQueues[bank].pop_front(); - - DPRINTF(RubyMemory, "Mem issue request%7d: %#08x %c " - "bank=%3x sched %c\n", req.m_msg_counter, req.m_addr, - req.m_is_mem_read? 'R':'W', - bank, m_event.scheduled() ? 'Y':'N'); - - if (req.m_msgptr) { // don't enqueue L3 writebacks - enqueueToDirectory(req, m_mem_ctl_latency + m_mem_fixed_delay); - } - m_oldRequest[bank] = 0; - markTfaw(rank); - m_bankBusyCounter[bank] = m_bank_busy_time; - m_busBusy_WhichRank = rank; - if (req.m_is_mem_read) { - m_profiler_ptr->profileMemRead(); - m_busBusyCounter_Basic = m_basic_bus_busy_time; - m_busBusyCounter_Write = m_basic_bus_busy_time + m_read_write_delay; - m_busBusyCounter_ReadNewRank = - m_basic_bus_busy_time + m_rank_rank_delay; - } else { - m_profiler_ptr->profileMemWrite(); - m_busBusyCounter_Basic = m_basic_bus_busy_time; - m_busBusyCounter_Write = m_basic_bus_busy_time; - m_busBusyCounter_ReadNewRank = m_basic_bus_busy_time; - } -} - -// executeCycle: This function is called once per memory clock cycle -// to simulate all the periodic hardware. -void -MemoryControl::executeCycle() -{ - // Keep track of time by counting down the busy counters: - for (int bank=0; bank < m_total_banks; bank++) { - if (m_bankBusyCounter[bank] > 0) m_bankBusyCounter[bank]--; - } - if (m_busBusyCounter_Write > 0) - m_busBusyCounter_Write--; - if (m_busBusyCounter_ReadNewRank > 0) - m_busBusyCounter_ReadNewRank--; - if (m_busBusyCounter_Basic > 0) - m_busBusyCounter_Basic--; - - // Count down the tFAW shift registers: - for (int rank=0; rank < m_total_ranks; rank++) { - if (m_tfaw_shift[rank] & 1) m_tfaw_count[rank]--; - m_tfaw_shift[rank] >>= 1; - } - - // After time period expires, latch an indication that we need a refresh. - // Disable refresh if in mem_fixed_delay mode. - if (!m_mem_fixed_delay) m_refresh_count--; - if (m_refresh_count == 0) { - m_refresh_count = m_refresh_period_system; - - // Are we overrunning our ability to refresh? - assert(m_need_refresh < 10); - m_need_refresh++; - } - - // If this batch of requests is all done, make a new batch: - m_ageCounter++; - int anyOld = 0; - for (int bank=0; bank < m_total_banks; bank++) { - anyOld |= m_oldRequest[bank]; - } - if (!anyOld) { - for (int bank=0; bank < m_total_banks; bank++) { - if (!m_bankQueues[bank].empty()) m_oldRequest[bank] = 1; - } - m_ageCounter = 0; - } - - // If randomness desired, re-randomize round-robin position each cycle - if (m_mem_random_arbitrate) { - m_roundRobin = random() % m_total_banks; - } - - // For each channel, scan round-robin, and pick an old, ready - // request and issue it. Treat a refresh request as if it were at - // the head of its bank queue. After we issue something, keep - // scanning the queues just to gather statistics about how many - // are waiting. If in mem_fixed_delay mode, we can issue more - // than one request per cycle. - int queueHeads = 0; - int banksIssued = 0; - for (int i = 0; i < m_total_banks; i++) { - m_roundRobin++; - if (m_roundRobin >= m_total_banks) m_roundRobin = 0; - issueRefresh(m_roundRobin); - int qs = m_bankQueues[m_roundRobin].size(); - if (qs > 1) { - m_profiler_ptr->profileMemBankQ(qs-1); - } - if (qs > 0) { - // we're not idle if anything is queued - m_idleCount = IDLECOUNT_MAX_VALUE; - queueHeads++; - if (queueReady(m_roundRobin)) { - issueRequest(m_roundRobin); - banksIssued++; - if (m_mem_fixed_delay) { - m_profiler_ptr->profileMemWaitCycles(m_mem_fixed_delay); - } - } - } - } - - // memWaitCycles is a redundant catch-all for the specific - // counters in queueReady - m_profiler_ptr->profileMemWaitCycles(queueHeads - banksIssued); - - // Check input queue and move anything to bank queues if not full. - // Since this is done here at the end of the cycle, there will - // always be at least one cycle of latency in the bank queue. We - // deliberately move at most one request per cycle (to simulate - // typical hardware). Note that if one bank queue fills up, other - // requests can get stuck behind it here. - if (!m_input_queue.empty()) { - // we're not idle if anything is pending - m_idleCount = IDLECOUNT_MAX_VALUE; - MemoryNode req = m_input_queue.front(); - int bank = getBank(req.m_addr); - if (m_bankQueues[bank].size() < m_bank_queue_size) { - m_input_queue.pop_front(); - m_bankQueues[bank].push_back(req); - } - m_profiler_ptr->profileMemInputQ(m_input_queue.size()); - } -} - -unsigned int -MemoryControl::drain(Event *de) -{ - DPRINTF(RubyMemory, "MemoryController drain\n"); - if(m_event.scheduled()) { - deschedule(m_event); - } - return 0; -} - -// wakeup: This function is called once per memory controller clock cycle. -void -MemoryControl::wakeup() -{ - DPRINTF(RubyMemory, "MemoryController wakeup\n"); - // execute everything - executeCycle(); - - m_idleCount--; - if (m_idleCount > 0) { - assert(!m_event.scheduled()); - schedule(m_event, curTick() + m_mem_bus_cycle_multiplier); - } -} - -MemoryControl * +RubyMemoryControl * RubyMemoryControlParams::create() { - return new MemoryControl(this); + return new RubyMemoryControl(this); } + |