f16c0a4a90
Draining is currently done by traversing the SimObject graph and calling drain()/drainResume() on the SimObjects. This is not ideal when non-SimObjects (e.g., ports) need draining since this means that SimObjects owning those objects need to be aware of this. This changeset moves the responsibility for finding objects that need draining from SimObjects and the Python-side of the simulator to the DrainManager. The DrainManager now maintains a set of all objects that need draining. To reduce the overhead in classes owning non-SimObjects that need draining, objects inheriting from Drainable now automatically register with the DrainManager. If such an object is destroyed, it is automatically unregistered. This means that drain() and drainResume() should never be called directly on a Drainable object. While implementing the new functionality, the DrainManager has now been made thread safe. In practice, this means that it takes a lock whenever it manipulates the set of Drainable objects since SimObjects in different threads may create Drainable objects dynamically. Similarly, the drain counter is now an atomic_uint, which ensures that it is manipulated correctly when objects signal that they are done draining. A nice side effect of these changes is that it makes the drain state changes stricter, which the simulation scripts can exploit to avoid redundant drains.
332 lines
12 KiB
C++
332 lines
12 KiB
C++
/*
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* Copyright (c) 2011-2015 ARM Limited
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* All rights reserved
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*
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* The license below extends only to copyright in the software and shall
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* not be construed as granting a license to any other intellectual
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* property including but not limited to intellectual property relating
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* to a hardware implementation of the functionality of the software
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* licensed hereunder. You may use the software subject to the license
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* terms below provided that you ensure that this notice is replicated
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* unmodified and in its entirety in all distributions of the software,
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* modified or unmodified, in source code or in binary form.
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*
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* Copyright (c) 2006 The Regents of The University of Michigan
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions are
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* met: redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer;
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* redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution;
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* neither the name of the copyright holders nor the names of its
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* contributors may be used to endorse or promote products derived from
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* this software without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
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* A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
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* OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
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* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
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* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
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* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*
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* Authors: Ali Saidi
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* Andreas Hansson
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* William Wang
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*/
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/**
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* @file
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* Definition of a non-coherent crossbar object.
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*/
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#include "base/misc.hh"
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#include "base/trace.hh"
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#include "debug/NoncoherentXBar.hh"
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#include "debug/XBar.hh"
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#include "mem/noncoherent_xbar.hh"
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NoncoherentXBar::NoncoherentXBar(const NoncoherentXBarParams *p)
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: BaseXBar(p)
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{
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// create the ports based on the size of the master and slave
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// vector ports, and the presence of the default port, the ports
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// are enumerated starting from zero
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for (int i = 0; i < p->port_master_connection_count; ++i) {
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std::string portName = csprintf("%s.master[%d]", name(), i);
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MasterPort* bp = new NoncoherentXBarMasterPort(portName, *this, i);
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masterPorts.push_back(bp);
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reqLayers.push_back(new ReqLayer(*bp, *this,
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csprintf(".reqLayer%d", i)));
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}
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// see if we have a default slave device connected and if so add
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// our corresponding master port
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if (p->port_default_connection_count) {
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defaultPortID = masterPorts.size();
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std::string portName = name() + ".default";
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MasterPort* bp = new NoncoherentXBarMasterPort(portName, *this,
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defaultPortID);
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masterPorts.push_back(bp);
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reqLayers.push_back(new ReqLayer(*bp, *this, csprintf(".reqLayer%d",
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defaultPortID)));
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}
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// create the slave ports, once again starting at zero
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for (int i = 0; i < p->port_slave_connection_count; ++i) {
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std::string portName = csprintf("%s.slave[%d]", name(), i);
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QueuedSlavePort* bp = new NoncoherentXBarSlavePort(portName, *this, i);
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slavePorts.push_back(bp);
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respLayers.push_back(new RespLayer(*bp, *this,
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csprintf(".respLayer%d", i)));
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}
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clearPortCache();
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}
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NoncoherentXBar::~NoncoherentXBar()
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{
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for (auto l: reqLayers)
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delete l;
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for (auto l: respLayers)
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delete l;
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}
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bool
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NoncoherentXBar::recvTimingReq(PacketPtr pkt, PortID slave_port_id)
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{
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// determine the source port based on the id
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SlavePort *src_port = slavePorts[slave_port_id];
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// we should never see express snoops on a non-coherent crossbar
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assert(!pkt->isExpressSnoop());
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// determine the destination based on the address
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PortID master_port_id = findPort(pkt->getAddr());
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// test if the layer should be considered occupied for the current
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// port
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if (!reqLayers[master_port_id]->tryTiming(src_port)) {
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DPRINTF(NoncoherentXBar, "recvTimingReq: src %s %s 0x%x BUSY\n",
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src_port->name(), pkt->cmdString(), pkt->getAddr());
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return false;
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}
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DPRINTF(NoncoherentXBar, "recvTimingReq: src %s %s 0x%x\n",
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src_port->name(), pkt->cmdString(), pkt->getAddr());
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// store size and command as they might be modified when
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// forwarding the packet
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unsigned int pkt_size = pkt->hasData() ? pkt->getSize() : 0;
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unsigned int pkt_cmd = pkt->cmdToIndex();
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// store the old header delay so we can restore it if needed
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Tick old_header_delay = pkt->headerDelay;
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// a request sees the frontend and forward latency
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Tick xbar_delay = (frontendLatency + forwardLatency) * clockPeriod();
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// set the packet header and payload delay
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calcPacketTiming(pkt, xbar_delay);
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// determine how long to be crossbar layer is busy
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Tick packetFinishTime = clockEdge(Cycles(1)) + pkt->payloadDelay;
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// before forwarding the packet (and possibly altering it),
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// remember if we are expecting a response
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const bool expect_response = pkt->needsResponse() &&
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!pkt->memInhibitAsserted();
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// since it is a normal request, attempt to send the packet
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bool success = masterPorts[master_port_id]->sendTimingReq(pkt);
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if (!success) {
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// inhibited packets should never be forced to retry
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assert(!pkt->memInhibitAsserted());
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DPRINTF(NoncoherentXBar, "recvTimingReq: src %s %s 0x%x RETRY\n",
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src_port->name(), pkt->cmdString(), pkt->getAddr());
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// restore the header delay as it is additive
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pkt->headerDelay = old_header_delay;
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// occupy until the header is sent
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reqLayers[master_port_id]->failedTiming(src_port,
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clockEdge(Cycles(1)));
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return false;
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}
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// remember where to route the response to
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if (expect_response) {
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assert(routeTo.find(pkt->req) == routeTo.end());
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routeTo[pkt->req] = slave_port_id;
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}
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reqLayers[master_port_id]->succeededTiming(packetFinishTime);
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// stats updates
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pktCount[slave_port_id][master_port_id]++;
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pktSize[slave_port_id][master_port_id] += pkt_size;
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transDist[pkt_cmd]++;
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return true;
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}
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bool
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NoncoherentXBar::recvTimingResp(PacketPtr pkt, PortID master_port_id)
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{
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// determine the source port based on the id
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MasterPort *src_port = masterPorts[master_port_id];
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// determine the destination
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const auto route_lookup = routeTo.find(pkt->req);
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assert(route_lookup != routeTo.end());
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const PortID slave_port_id = route_lookup->second;
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assert(slave_port_id != InvalidPortID);
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assert(slave_port_id < respLayers.size());
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// test if the layer should be considered occupied for the current
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// port
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if (!respLayers[slave_port_id]->tryTiming(src_port)) {
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DPRINTF(NoncoherentXBar, "recvTimingResp: src %s %s 0x%x BUSY\n",
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src_port->name(), pkt->cmdString(), pkt->getAddr());
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return false;
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}
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DPRINTF(NoncoherentXBar, "recvTimingResp: src %s %s 0x%x\n",
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src_port->name(), pkt->cmdString(), pkt->getAddr());
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// store size and command as they might be modified when
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// forwarding the packet
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unsigned int pkt_size = pkt->hasData() ? pkt->getSize() : 0;
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unsigned int pkt_cmd = pkt->cmdToIndex();
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// a response sees the response latency
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Tick xbar_delay = responseLatency * clockPeriod();
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// set the packet header and payload delay
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calcPacketTiming(pkt, xbar_delay);
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// determine how long to be crossbar layer is busy
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Tick packetFinishTime = clockEdge(Cycles(1)) + pkt->payloadDelay;
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// send the packet through the destination slave port, and pay for
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// any outstanding latency
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Tick latency = pkt->headerDelay;
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pkt->headerDelay = 0;
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slavePorts[slave_port_id]->schedTimingResp(pkt, curTick() + latency);
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// remove the request from the routing table
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routeTo.erase(route_lookup);
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respLayers[slave_port_id]->succeededTiming(packetFinishTime);
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// stats updates
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pktCount[slave_port_id][master_port_id]++;
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pktSize[slave_port_id][master_port_id] += pkt_size;
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transDist[pkt_cmd]++;
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return true;
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}
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void
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NoncoherentXBar::recvReqRetry(PortID master_port_id)
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{
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// responses never block on forwarding them, so the retry will
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// always be coming from a port to which we tried to forward a
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// request
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reqLayers[master_port_id]->recvRetry();
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}
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Tick
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NoncoherentXBar::recvAtomic(PacketPtr pkt, PortID slave_port_id)
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{
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DPRINTF(NoncoherentXBar, "recvAtomic: packet src %s addr 0x%x cmd %s\n",
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slavePorts[slave_port_id]->name(), pkt->getAddr(),
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pkt->cmdString());
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unsigned int pkt_size = pkt->hasData() ? pkt->getSize() : 0;
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unsigned int pkt_cmd = pkt->cmdToIndex();
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// determine the destination port
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PortID master_port_id = findPort(pkt->getAddr());
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// stats updates for the request
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pktCount[slave_port_id][master_port_id]++;
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pktSize[slave_port_id][master_port_id] += pkt_size;
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transDist[pkt_cmd]++;
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// forward the request to the appropriate destination
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Tick response_latency = masterPorts[master_port_id]->sendAtomic(pkt);
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// add the response data
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if (pkt->isResponse()) {
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pkt_size = pkt->hasData() ? pkt->getSize() : 0;
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pkt_cmd = pkt->cmdToIndex();
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// stats updates
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pktCount[slave_port_id][master_port_id]++;
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pktSize[slave_port_id][master_port_id] += pkt_size;
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transDist[pkt_cmd]++;
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}
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// @todo: Not setting first-word time
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pkt->payloadDelay = response_latency;
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return response_latency;
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}
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void
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NoncoherentXBar::recvFunctional(PacketPtr pkt, PortID slave_port_id)
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{
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if (!pkt->isPrint()) {
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// don't do DPRINTFs on PrintReq as it clutters up the output
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DPRINTF(NoncoherentXBar,
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"recvFunctional: packet src %s addr 0x%x cmd %s\n",
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slavePorts[slave_port_id]->name(), pkt->getAddr(),
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pkt->cmdString());
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}
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// since our slave ports are queued ports we need to check them as well
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for (const auto& p : slavePorts) {
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// if we find a response that has the data, then the
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// downstream caches/memories may be out of date, so simply stop
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// here
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if (p->checkFunctional(pkt)) {
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if (pkt->needsResponse())
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pkt->makeResponse();
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return;
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}
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}
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// determine the destination port
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PortID dest_id = findPort(pkt->getAddr());
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// forward the request to the appropriate destination
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masterPorts[dest_id]->sendFunctional(pkt);
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}
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NoncoherentXBar*
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NoncoherentXBarParams::create()
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{
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return new NoncoherentXBar(this);
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}
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void
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NoncoherentXBar::regStats()
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{
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// register the stats of the base class and our layers
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BaseXBar::regStats();
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for (auto l: reqLayers)
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l->regStats();
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for (auto l: respLayers)
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l->regStats();
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}
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