coherent_xbar.cc revision 12345
12497SN/A/* 212241Snikos.nikoleris@arm.com * Copyright (c) 2011-2017 ARM Limited 38711SN/A * All rights reserved 48711SN/A * 58711SN/A * The license below extends only to copyright in the software and shall 68711SN/A * not be construed as granting a license to any other intellectual 78711SN/A * property including but not limited to intellectual property relating 88711SN/A * to a hardware implementation of the functionality of the software 98711SN/A * licensed hereunder. You may use the software subject to the license 108711SN/A * terms below provided that you ensure that this notice is replicated 118711SN/A * unmodified and in its entirety in all distributions of the software, 128711SN/A * modified or unmodified, in source code or in binary form. 138711SN/A * 142497SN/A * Copyright (c) 2006 The Regents of The University of Michigan 152497SN/A * All rights reserved. 162497SN/A * 172497SN/A * Redistribution and use in source and binary forms, with or without 182497SN/A * modification, are permitted provided that the following conditions are 192497SN/A * met: redistributions of source code must retain the above copyright 202497SN/A * notice, this list of conditions and the following disclaimer; 212497SN/A * redistributions in binary form must reproduce the above copyright 222497SN/A * notice, this list of conditions and the following disclaimer in the 232497SN/A * documentation and/or other materials provided with the distribution; 242497SN/A * neither the name of the copyright holders nor the names of its 252497SN/A * contributors may be used to endorse or promote products derived from 262497SN/A * this software without specific prior written permission. 272497SN/A * 282497SN/A * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS 292497SN/A * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 302497SN/A * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR 312497SN/A * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT 322497SN/A * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, 332497SN/A * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT 342497SN/A * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 352497SN/A * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 362497SN/A * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 372497SN/A * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE 382497SN/A * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 392665SN/A * 402665SN/A * Authors: Ali Saidi 418715SN/A * Andreas Hansson 428922SN/A * William Wang 432497SN/A */ 442497SN/A 452497SN/A/** 462982SN/A * @file 4710405Sandreas.hansson@arm.com * Definition of a crossbar object. 482497SN/A */ 492497SN/A 5011793Sbrandon.potter@amd.com#include "mem/coherent_xbar.hh" 5111793Sbrandon.potter@amd.com 5212334Sgabeblack@google.com#include "base/logging.hh" 532548SN/A#include "base/trace.hh" 5410405Sandreas.hansson@arm.com#include "debug/AddrRanges.hh" 5510405Sandreas.hansson@arm.com#include "debug/CoherentXBar.hh" 569524SN/A#include "sim/system.hh" 572497SN/A 5810405Sandreas.hansson@arm.comCoherentXBar::CoherentXBar(const CoherentXBarParams *p) 5910719SMarco.Balboni@ARM.com : BaseXBar(p), system(p->system), snoopFilter(p->snoop_filter), 6011334Sandreas.hansson@arm.com snoopResponseLatency(p->snoop_response_latency), 6112341Snikos.nikoleris@arm.com pointOfCoherency(p->point_of_coherency), 6212341Snikos.nikoleris@arm.com pointOfUnification(p->point_of_unification) 637523SN/A{ 648851SN/A // create the ports based on the size of the master and slave 658948SN/A // vector ports, and the presence of the default port, the ports 668948SN/A // are enumerated starting from zero 678851SN/A for (int i = 0; i < p->port_master_connection_count; ++i) { 689095SN/A std::string portName = csprintf("%s.master[%d]", name(), i); 6910405Sandreas.hansson@arm.com MasterPort* bp = new CoherentXBarMasterPort(portName, *this, i); 708922SN/A masterPorts.push_back(bp); 719715SN/A reqLayers.push_back(new ReqLayer(*bp, *this, 729715SN/A csprintf(".reqLayer%d", i))); 7310713Sandreas.hansson@arm.com snoopLayers.push_back(new SnoopRespLayer(*bp, *this, 7410713Sandreas.hansson@arm.com csprintf(".snoopLayer%d", i))); 758851SN/A } 768851SN/A 778948SN/A // see if we have a default slave device connected and if so add 788948SN/A // our corresponding master port 798915SN/A if (p->port_default_connection_count) { 809031SN/A defaultPortID = masterPorts.size(); 819095SN/A std::string portName = name() + ".default"; 8210405Sandreas.hansson@arm.com MasterPort* bp = new CoherentXBarMasterPort(portName, *this, 839036SN/A defaultPortID); 848922SN/A masterPorts.push_back(bp); 859715SN/A reqLayers.push_back(new ReqLayer(*bp, *this, csprintf(".reqLayer%d", 869715SN/A defaultPortID))); 8710713Sandreas.hansson@arm.com snoopLayers.push_back(new SnoopRespLayer(*bp, *this, 8810713Sandreas.hansson@arm.com csprintf(".snoopLayer%d", 8910713Sandreas.hansson@arm.com defaultPortID))); 908915SN/A } 918915SN/A 928948SN/A // create the slave ports, once again starting at zero 938851SN/A for (int i = 0; i < p->port_slave_connection_count; ++i) { 949095SN/A std::string portName = csprintf("%s.slave[%d]", name(), i); 9510888Sandreas.hansson@arm.com QueuedSlavePort* bp = new CoherentXBarSlavePort(portName, *this, i); 968922SN/A slavePorts.push_back(bp); 979715SN/A respLayers.push_back(new RespLayer(*bp, *this, 989715SN/A csprintf(".respLayer%d", i))); 999716SN/A snoopRespPorts.push_back(new SnoopRespPort(*bp, *this)); 1008851SN/A } 1018851SN/A 1027523SN/A clearPortCache(); 1037523SN/A} 1047523SN/A 10510405Sandreas.hansson@arm.comCoherentXBar::~CoherentXBar() 1069715SN/A{ 10710405Sandreas.hansson@arm.com for (auto l: reqLayers) 10810405Sandreas.hansson@arm.com delete l; 10910405Sandreas.hansson@arm.com for (auto l: respLayers) 11010405Sandreas.hansson@arm.com delete l; 11110405Sandreas.hansson@arm.com for (auto l: snoopLayers) 11210405Sandreas.hansson@arm.com delete l; 11310405Sandreas.hansson@arm.com for (auto p: snoopRespPorts) 11410405Sandreas.hansson@arm.com delete p; 1159715SN/A} 1169715SN/A 1172568SN/Avoid 11810405Sandreas.hansson@arm.comCoherentXBar::init() 1192568SN/A{ 12010405Sandreas.hansson@arm.com BaseXBar::init(); 1219278SN/A 1228948SN/A // iterate over our slave ports and determine which of our 1238948SN/A // neighbouring master ports are snooping and add them as snoopers 12410405Sandreas.hansson@arm.com for (const auto& p: slavePorts) { 1259088SN/A // check if the connected master port is snooping 12610405Sandreas.hansson@arm.com if (p->isSnooping()) { 12710405Sandreas.hansson@arm.com DPRINTF(AddrRanges, "Adding snooping master %s\n", 12810405Sandreas.hansson@arm.com p->getMasterPort().name()); 12910405Sandreas.hansson@arm.com snoopPorts.push_back(p); 1308711SN/A } 1318711SN/A } 1322568SN/A 1339036SN/A if (snoopPorts.empty()) 13410405Sandreas.hansson@arm.com warn("CoherentXBar %s has no snooping ports attached!\n", name()); 13511133Sandreas.hansson@arm.com 13611133Sandreas.hansson@arm.com // inform the snoop filter about the slave ports so it can create 13711133Sandreas.hansson@arm.com // its own internal representation 13811133Sandreas.hansson@arm.com if (snoopFilter) 13911133Sandreas.hansson@arm.com snoopFilter->setSlavePorts(slavePorts); 1403244SN/A} 1413244SN/A 1428948SN/Abool 14310405Sandreas.hansson@arm.comCoherentXBar::recvTimingReq(PacketPtr pkt, PortID slave_port_id) 1443244SN/A{ 1458975SN/A // determine the source port based on the id 1469032SN/A SlavePort *src_port = slavePorts[slave_port_id]; 1473244SN/A 1489091SN/A // remember if the packet is an express snoop 1499091SN/A bool is_express_snoop = pkt->isExpressSnoop(); 15011284Sandreas.hansson@arm.com bool cache_responding = pkt->cacheResponding(); 15110656Sandreas.hansson@arm.com // for normal requests, going downstream, the express snoop flag 15211284Sandreas.hansson@arm.com // and the cache responding flag should always be the same 15311284Sandreas.hansson@arm.com assert(is_express_snoop == cache_responding); 1549091SN/A 1559612SN/A // determine the destination based on the address 1569712SN/A PortID master_port_id = findPort(pkt->getAddr()); 1579612SN/A 15810405Sandreas.hansson@arm.com // test if the crossbar should be considered occupied for the current 1599033SN/A // port, and exclude express snoops from the check 1609715SN/A if (!is_express_snoop && !reqLayers[master_port_id]->tryTiming(src_port)) { 16111744Snikos.nikoleris@arm.com DPRINTF(CoherentXBar, "%s: src %s packet %s BUSY\n", __func__, 16211744Snikos.nikoleris@arm.com src_port->name(), pkt->print()); 1633244SN/A return false; 1643244SN/A } 1653244SN/A 16611744Snikos.nikoleris@arm.com DPRINTF(CoherentXBar, "%s: src %s packet %s\n", __func__, 16711744Snikos.nikoleris@arm.com src_port->name(), pkt->print()); 1685197SN/A 1699712SN/A // store size and command as they might be modified when 1709712SN/A // forwarding the packet 1719712SN/A unsigned int pkt_size = pkt->hasData() ? pkt->getSize() : 0; 1729712SN/A unsigned int pkt_cmd = pkt->cmdToIndex(); 1739712SN/A 17410719SMarco.Balboni@ARM.com // store the old header delay so we can restore it if needed 17510719SMarco.Balboni@ARM.com Tick old_header_delay = pkt->headerDelay; 17610719SMarco.Balboni@ARM.com 17710719SMarco.Balboni@ARM.com // a request sees the frontend and forward latency 17810719SMarco.Balboni@ARM.com Tick xbar_delay = (frontendLatency + forwardLatency) * clockPeriod(); 17910719SMarco.Balboni@ARM.com 18010719SMarco.Balboni@ARM.com // set the packet header and payload delay 18110719SMarco.Balboni@ARM.com calcPacketTiming(pkt, xbar_delay); 18210719SMarco.Balboni@ARM.com 18310719SMarco.Balboni@ARM.com // determine how long to be crossbar layer is busy 18410719SMarco.Balboni@ARM.com Tick packetFinishTime = clockEdge(Cycles(1)) + pkt->payloadDelay; 1854912SN/A 18612345Snikos.nikoleris@arm.com const bool snoop_caches = !system->bypassCaches() && 18712345Snikos.nikoleris@arm.com pkt->cmd != MemCmd::WriteClean; 18812345Snikos.nikoleris@arm.com if (snoop_caches) { 18911127Sandreas.hansson@arm.com assert(pkt->snoopDelay == 0); 19011127Sandreas.hansson@arm.com 1918979SN/A // the packet is a memory-mapped request and should be 1928979SN/A // broadcasted to our snoopers but the source 19310402SN/A if (snoopFilter) { 19410402SN/A // check with the snoop filter where to forward this packet 19510402SN/A auto sf_res = snoopFilter->lookupRequest(pkt, *src_port); 19611126Sandreas.hansson@arm.com // the time required by a packet to be delivered through 19711126Sandreas.hansson@arm.com // the xbar has to be charged also with to lookup latency 19811126Sandreas.hansson@arm.com // of the snoop filter 19910719SMarco.Balboni@ARM.com pkt->headerDelay += sf_res.second * clockPeriod(); 20011744Snikos.nikoleris@arm.com DPRINTF(CoherentXBar, "%s: src %s packet %s SF size: %i lat: %i\n", 20111744Snikos.nikoleris@arm.com __func__, src_port->name(), pkt->print(), 20211744Snikos.nikoleris@arm.com sf_res.first.size(), sf_res.second); 20311196Sali.jafri@arm.com 20411199Sandreas.hansson@arm.com if (pkt->isEviction()) { 20511196Sali.jafri@arm.com // for block-evicting packets, i.e. writebacks and 20611196Sali.jafri@arm.com // clean evictions, there is no need to snoop up, as 20711196Sali.jafri@arm.com // all we do is determine if the block is cached or 20811196Sali.jafri@arm.com // not, instead just set it here based on the snoop 20911196Sali.jafri@arm.com // filter result 21011196Sali.jafri@arm.com if (!sf_res.first.empty()) 21111196Sali.jafri@arm.com pkt->setBlockCached(); 21211196Sali.jafri@arm.com } else { 21311196Sali.jafri@arm.com forwardTiming(pkt, slave_port_id, sf_res.first); 21411196Sali.jafri@arm.com } 21510402SN/A } else { 21610402SN/A forwardTiming(pkt, slave_port_id); 21710402SN/A } 21811127Sandreas.hansson@arm.com 21911127Sandreas.hansson@arm.com // add the snoop delay to our header delay, and then reset it 22011127Sandreas.hansson@arm.com pkt->headerDelay += pkt->snoopDelay; 22111127Sandreas.hansson@arm.com pkt->snoopDelay = 0; 2228979SN/A } 2238948SN/A 22411334Sandreas.hansson@arm.com // set up a sensible starting point 22511334Sandreas.hansson@arm.com bool success = true; 22610883Sali.jafri@arm.com 22711284Sandreas.hansson@arm.com // remember if the packet will generate a snoop response by 22811284Sandreas.hansson@arm.com // checking if a cache set the cacheResponding flag during the 22911284Sandreas.hansson@arm.com // snooping above 23011284Sandreas.hansson@arm.com const bool expect_snoop_resp = !cache_responding && pkt->cacheResponding(); 23111334Sandreas.hansson@arm.com bool expect_response = pkt->needsResponse() && !pkt->cacheResponding(); 2328915SN/A 23311334Sandreas.hansson@arm.com const bool sink_packet = sinkPacket(pkt); 23411334Sandreas.hansson@arm.com 23511334Sandreas.hansson@arm.com // in certain cases the crossbar is responsible for responding 23611334Sandreas.hansson@arm.com bool respond_directly = false; 23711544Snikos.nikoleris@arm.com // store the original address as an address mapper could possibly 23811544Snikos.nikoleris@arm.com // modify the address upon a sendTimingRequest 23911544Snikos.nikoleris@arm.com const Addr addr(pkt->getAddr()); 24011334Sandreas.hansson@arm.com if (sink_packet) { 24111744Snikos.nikoleris@arm.com DPRINTF(CoherentXBar, "%s: Not forwarding %s\n", __func__, 24211744Snikos.nikoleris@arm.com pkt->print()); 24311334Sandreas.hansson@arm.com } else { 24411334Sandreas.hansson@arm.com // determine if we are forwarding the packet, or responding to 24511334Sandreas.hansson@arm.com // it 24611334Sandreas.hansson@arm.com if (!pointOfCoherency || pkt->isRead() || pkt->isWrite()) { 24711334Sandreas.hansson@arm.com // if we are passing on, rather than sinking, a packet to 24811334Sandreas.hansson@arm.com // which an upstream cache has committed to responding, 24911334Sandreas.hansson@arm.com // the line was needs writable, and the responding only 25011334Sandreas.hansson@arm.com // had an Owned copy, so we need to immidiately let the 25111334Sandreas.hansson@arm.com // downstream caches know, bypass any flow control 25211334Sandreas.hansson@arm.com if (pkt->cacheResponding()) { 25311334Sandreas.hansson@arm.com pkt->setExpressSnoop(); 25411334Sandreas.hansson@arm.com } 25511334Sandreas.hansson@arm.com 25611334Sandreas.hansson@arm.com // since it is a normal request, attempt to send the packet 25711334Sandreas.hansson@arm.com success = masterPorts[master_port_id]->sendTimingReq(pkt); 25811334Sandreas.hansson@arm.com } else { 25911334Sandreas.hansson@arm.com // no need to forward, turn this packet around and respond 26011334Sandreas.hansson@arm.com // directly 26111334Sandreas.hansson@arm.com assert(pkt->needsResponse()); 26211334Sandreas.hansson@arm.com 26311334Sandreas.hansson@arm.com respond_directly = true; 26411334Sandreas.hansson@arm.com assert(!expect_snoop_resp); 26511334Sandreas.hansson@arm.com expect_response = false; 26611334Sandreas.hansson@arm.com } 26711334Sandreas.hansson@arm.com } 2688948SN/A 26912345Snikos.nikoleris@arm.com if (snoopFilter && snoop_caches) { 27010402SN/A // Let the snoop filter know about the success of the send operation 27111605Snikos.nikoleris@arm.com snoopFilter->finishRequest(!success, addr, pkt->isSecure()); 27210402SN/A } 27310402SN/A 27410656Sandreas.hansson@arm.com // check if we were successful in sending the packet onwards 27510656Sandreas.hansson@arm.com if (!success) { 27611284Sandreas.hansson@arm.com // express snoops should never be forced to retry 27710656Sandreas.hansson@arm.com assert(!is_express_snoop); 27810656Sandreas.hansson@arm.com 27910719SMarco.Balboni@ARM.com // restore the header delay 28010719SMarco.Balboni@ARM.com pkt->headerDelay = old_header_delay; 28110656Sandreas.hansson@arm.com 28211744Snikos.nikoleris@arm.com DPRINTF(CoherentXBar, "%s: src %s packet %s RETRY\n", __func__, 28311744Snikos.nikoleris@arm.com src_port->name(), pkt->print()); 28410656Sandreas.hansson@arm.com 28510656Sandreas.hansson@arm.com // update the layer state and schedule an idle event 28610656Sandreas.hansson@arm.com reqLayers[master_port_id]->failedTiming(src_port, 28710719SMarco.Balboni@ARM.com clockEdge(Cycles(1))); 2889091SN/A } else { 28910656Sandreas.hansson@arm.com // express snoops currently bypass the crossbar state entirely 29010656Sandreas.hansson@arm.com if (!is_express_snoop) { 29110656Sandreas.hansson@arm.com // if this particular request will generate a snoop 29210656Sandreas.hansson@arm.com // response 29310656Sandreas.hansson@arm.com if (expect_snoop_resp) { 29410656Sandreas.hansson@arm.com // we should never have an exsiting request outstanding 29510656Sandreas.hansson@arm.com assert(outstandingSnoop.find(pkt->req) == 29610656Sandreas.hansson@arm.com outstandingSnoop.end()); 29710656Sandreas.hansson@arm.com outstandingSnoop.insert(pkt->req); 2988948SN/A 29910656Sandreas.hansson@arm.com // basic sanity check on the outstanding snoops 30010656Sandreas.hansson@arm.com panic_if(outstandingSnoop.size() > 512, 30110656Sandreas.hansson@arm.com "Outstanding snoop requests exceeded 512\n"); 30210656Sandreas.hansson@arm.com } 3038948SN/A 30410656Sandreas.hansson@arm.com // remember where to route the normal response to 30510656Sandreas.hansson@arm.com if (expect_response || expect_snoop_resp) { 30610656Sandreas.hansson@arm.com assert(routeTo.find(pkt->req) == routeTo.end()); 30710656Sandreas.hansson@arm.com routeTo[pkt->req] = slave_port_id; 3089549SN/A 30910656Sandreas.hansson@arm.com panic_if(routeTo.size() > 512, 31010656Sandreas.hansson@arm.com "Routing table exceeds 512 packets\n"); 31110656Sandreas.hansson@arm.com } 3128948SN/A 31310405Sandreas.hansson@arm.com // update the layer state and schedule an idle event 3149715SN/A reqLayers[master_port_id]->succeededTiming(packetFinishTime); 3159091SN/A } 3168975SN/A 31710656Sandreas.hansson@arm.com // stats updates only consider packets that were successfully sent 3189712SN/A pktCount[slave_port_id][master_port_id]++; 31910405Sandreas.hansson@arm.com pktSize[slave_port_id][master_port_id] += pkt_size; 3209712SN/A transDist[pkt_cmd]++; 32110656Sandreas.hansson@arm.com 32211564Sdavid.guillen@arm.com if (is_express_snoop) { 32310656Sandreas.hansson@arm.com snoops++; 32411564Sdavid.guillen@arm.com snoopTraffic += pkt_size; 32511564Sdavid.guillen@arm.com } 3269712SN/A } 3279712SN/A 32811334Sandreas.hansson@arm.com if (sink_packet) 32911334Sandreas.hansson@arm.com // queue the packet for deletion 33011334Sandreas.hansson@arm.com pendingDelete.reset(pkt); 33111334Sandreas.hansson@arm.com 33211334Sandreas.hansson@arm.com if (respond_directly) { 33311334Sandreas.hansson@arm.com assert(pkt->needsResponse()); 33411334Sandreas.hansson@arm.com assert(success); 33511334Sandreas.hansson@arm.com 33611334Sandreas.hansson@arm.com pkt->makeResponse(); 33711334Sandreas.hansson@arm.com 33811334Sandreas.hansson@arm.com if (snoopFilter && !system->bypassCaches()) { 33911334Sandreas.hansson@arm.com // let the snoop filter inspect the response and update its state 34011334Sandreas.hansson@arm.com snoopFilter->updateResponse(pkt, *slavePorts[slave_port_id]); 34111334Sandreas.hansson@arm.com } 34211334Sandreas.hansson@arm.com 34311334Sandreas.hansson@arm.com Tick response_time = clockEdge() + pkt->headerDelay; 34411334Sandreas.hansson@arm.com pkt->headerDelay = 0; 34511334Sandreas.hansson@arm.com 34611334Sandreas.hansson@arm.com slavePorts[slave_port_id]->schedTimingResp(pkt, response_time); 34711334Sandreas.hansson@arm.com } 34811334Sandreas.hansson@arm.com 3499091SN/A return success; 3508975SN/A} 3518975SN/A 3528975SN/Abool 35310405Sandreas.hansson@arm.comCoherentXBar::recvTimingResp(PacketPtr pkt, PortID master_port_id) 3548975SN/A{ 3558975SN/A // determine the source port based on the id 3569032SN/A MasterPort *src_port = masterPorts[master_port_id]; 3578975SN/A 35810656Sandreas.hansson@arm.com // determine the destination 35910656Sandreas.hansson@arm.com const auto route_lookup = routeTo.find(pkt->req); 36010656Sandreas.hansson@arm.com assert(route_lookup != routeTo.end()); 36110656Sandreas.hansson@arm.com const PortID slave_port_id = route_lookup->second; 36210572Sandreas.hansson@arm.com assert(slave_port_id != InvalidPortID); 36310572Sandreas.hansson@arm.com assert(slave_port_id < respLayers.size()); 3649713SN/A 36510405Sandreas.hansson@arm.com // test if the crossbar should be considered occupied for the 36610405Sandreas.hansson@arm.com // current port 3679715SN/A if (!respLayers[slave_port_id]->tryTiming(src_port)) { 36811744Snikos.nikoleris@arm.com DPRINTF(CoherentXBar, "%s: src %s packet %s BUSY\n", __func__, 36911744Snikos.nikoleris@arm.com src_port->name(), pkt->print()); 3708975SN/A return false; 3718975SN/A } 3728975SN/A 37311744Snikos.nikoleris@arm.com DPRINTF(CoherentXBar, "%s: src %s packet %s\n", __func__, 37411744Snikos.nikoleris@arm.com src_port->name(), pkt->print()); 3758975SN/A 3769712SN/A // store size and command as they might be modified when 3779712SN/A // forwarding the packet 3789712SN/A unsigned int pkt_size = pkt->hasData() ? pkt->getSize() : 0; 3799712SN/A unsigned int pkt_cmd = pkt->cmdToIndex(); 3809712SN/A 38110719SMarco.Balboni@ARM.com // a response sees the response latency 38210719SMarco.Balboni@ARM.com Tick xbar_delay = responseLatency * clockPeriod(); 38310719SMarco.Balboni@ARM.com 38410719SMarco.Balboni@ARM.com // set the packet header and payload delay 38510719SMarco.Balboni@ARM.com calcPacketTiming(pkt, xbar_delay); 38610719SMarco.Balboni@ARM.com 38710719SMarco.Balboni@ARM.com // determine how long to be crossbar layer is busy 38810719SMarco.Balboni@ARM.com Tick packetFinishTime = clockEdge(Cycles(1)) + pkt->payloadDelay; 3898975SN/A 39010821Sandreas.hansson@arm.com if (snoopFilter && !system->bypassCaches()) { 39110402SN/A // let the snoop filter inspect the response and update its state 39210402SN/A snoopFilter->updateResponse(pkt, *slavePorts[slave_port_id]); 39310402SN/A } 39410402SN/A 39510888Sandreas.hansson@arm.com // send the packet through the destination slave port and pay for 39610888Sandreas.hansson@arm.com // any outstanding header delay 39710888Sandreas.hansson@arm.com Tick latency = pkt->headerDelay; 39810888Sandreas.hansson@arm.com pkt->headerDelay = 0; 39910888Sandreas.hansson@arm.com slavePorts[slave_port_id]->schedTimingResp(pkt, curTick() + latency); 4008975SN/A 40110656Sandreas.hansson@arm.com // remove the request from the routing table 40210656Sandreas.hansson@arm.com routeTo.erase(route_lookup); 40310656Sandreas.hansson@arm.com 4049715SN/A respLayers[slave_port_id]->succeededTiming(packetFinishTime); 4058975SN/A 4069712SN/A // stats updates 4079712SN/A pktCount[slave_port_id][master_port_id]++; 40810405Sandreas.hansson@arm.com pktSize[slave_port_id][master_port_id] += pkt_size; 4099712SN/A transDist[pkt_cmd]++; 4109712SN/A 4118975SN/A return true; 4128975SN/A} 4138975SN/A 4148975SN/Avoid 41510405Sandreas.hansson@arm.comCoherentXBar::recvTimingSnoopReq(PacketPtr pkt, PortID master_port_id) 4168975SN/A{ 41711744Snikos.nikoleris@arm.com DPRINTF(CoherentXBar, "%s: src %s packet %s\n", __func__, 41811744Snikos.nikoleris@arm.com masterPorts[master_port_id]->name(), pkt->print()); 4198975SN/A 4209712SN/A // update stats here as we know the forwarding will succeed 42111564Sdavid.guillen@arm.com unsigned int pkt_size = pkt->hasData() ? pkt->getSize() : 0; 4229712SN/A transDist[pkt->cmdToIndex()]++; 42310405Sandreas.hansson@arm.com snoops++; 42411564Sdavid.guillen@arm.com snoopTraffic += pkt_size; 4259712SN/A 4268975SN/A // we should only see express snoops from caches 4278975SN/A assert(pkt->isExpressSnoop()); 4288975SN/A 42911127Sandreas.hansson@arm.com // set the packet header and payload delay, for now use forward latency 43011127Sandreas.hansson@arm.com // @todo Assess the choice of latency further 43111127Sandreas.hansson@arm.com calcPacketTiming(pkt, forwardLatency * clockPeriod()); 43211127Sandreas.hansson@arm.com 43311284Sandreas.hansson@arm.com // remember if a cache has already committed to responding so we 43411284Sandreas.hansson@arm.com // can see if it changes during the snooping 43511284Sandreas.hansson@arm.com const bool cache_responding = pkt->cacheResponding(); 4369032SN/A 43711127Sandreas.hansson@arm.com assert(pkt->snoopDelay == 0); 43811127Sandreas.hansson@arm.com 43910402SN/A if (snoopFilter) { 44010402SN/A // let the Snoop Filter work its magic and guide probing 44110402SN/A auto sf_res = snoopFilter->lookupSnoop(pkt); 44211126Sandreas.hansson@arm.com // the time required by a packet to be delivered through 44311126Sandreas.hansson@arm.com // the xbar has to be charged also with to lookup latency 44411126Sandreas.hansson@arm.com // of the snoop filter 44511126Sandreas.hansson@arm.com pkt->headerDelay += sf_res.second * clockPeriod(); 44611744Snikos.nikoleris@arm.com DPRINTF(CoherentXBar, "%s: src %s packet %s SF size: %i lat: %i\n", 44711744Snikos.nikoleris@arm.com __func__, masterPorts[master_port_id]->name(), pkt->print(), 44811744Snikos.nikoleris@arm.com sf_res.first.size(), sf_res.second); 44910402SN/A 45010402SN/A // forward to all snoopers 45110402SN/A forwardTiming(pkt, InvalidPortID, sf_res.first); 45210402SN/A } else { 45310402SN/A forwardTiming(pkt, InvalidPortID); 45410402SN/A } 4558975SN/A 45611127Sandreas.hansson@arm.com // add the snoop delay to our header delay, and then reset it 45711127Sandreas.hansson@arm.com pkt->headerDelay += pkt->snoopDelay; 45811127Sandreas.hansson@arm.com pkt->snoopDelay = 0; 45911127Sandreas.hansson@arm.com 46010656Sandreas.hansson@arm.com // if we can expect a response, remember how to route it 46111284Sandreas.hansson@arm.com if (!cache_responding && pkt->cacheResponding()) { 46210656Sandreas.hansson@arm.com assert(routeTo.find(pkt->req) == routeTo.end()); 46310656Sandreas.hansson@arm.com routeTo[pkt->req] = master_port_id; 46410656Sandreas.hansson@arm.com } 46510656Sandreas.hansson@arm.com 4668975SN/A // a snoop request came from a connected slave device (one of 4678975SN/A // our master ports), and if it is not coming from the slave 4688975SN/A // device responsible for the address range something is 4698975SN/A // wrong, hence there is nothing further to do as the packet 4708975SN/A // would be going back to where it came from 4719032SN/A assert(master_port_id == findPort(pkt->getAddr())); 4728975SN/A} 4738975SN/A 4748975SN/Abool 47510405Sandreas.hansson@arm.comCoherentXBar::recvTimingSnoopResp(PacketPtr pkt, PortID slave_port_id) 4768975SN/A{ 4778975SN/A // determine the source port based on the id 4789032SN/A SlavePort* src_port = slavePorts[slave_port_id]; 4798975SN/A 48010656Sandreas.hansson@arm.com // get the destination 48110656Sandreas.hansson@arm.com const auto route_lookup = routeTo.find(pkt->req); 48210656Sandreas.hansson@arm.com assert(route_lookup != routeTo.end()); 48310656Sandreas.hansson@arm.com const PortID dest_port_id = route_lookup->second; 48410572Sandreas.hansson@arm.com assert(dest_port_id != InvalidPortID); 4859714SN/A 4869714SN/A // determine if the response is from a snoop request we 4879714SN/A // created as the result of a normal request (in which case it 48810656Sandreas.hansson@arm.com // should be in the outstandingSnoop), or if we merely forwarded 4899714SN/A // someone else's snoop request 49010656Sandreas.hansson@arm.com const bool forwardAsSnoop = outstandingSnoop.find(pkt->req) == 49110656Sandreas.hansson@arm.com outstandingSnoop.end(); 4929714SN/A 49310405Sandreas.hansson@arm.com // test if the crossbar should be considered occupied for the 49410405Sandreas.hansson@arm.com // current port, note that the check is bypassed if the response 49510405Sandreas.hansson@arm.com // is being passed on as a normal response since this is occupying 49610405Sandreas.hansson@arm.com // the response layer rather than the snoop response layer 4979715SN/A if (forwardAsSnoop) { 49810572Sandreas.hansson@arm.com assert(dest_port_id < snoopLayers.size()); 4999715SN/A if (!snoopLayers[dest_port_id]->tryTiming(src_port)) { 50011744Snikos.nikoleris@arm.com DPRINTF(CoherentXBar, "%s: src %s packet %s BUSY\n", __func__, 50111744Snikos.nikoleris@arm.com src_port->name(), pkt->print()); 5029715SN/A return false; 5039715SN/A } 5049716SN/A } else { 5059716SN/A // get the master port that mirrors this slave port internally 5069716SN/A MasterPort* snoop_port = snoopRespPorts[slave_port_id]; 50710572Sandreas.hansson@arm.com assert(dest_port_id < respLayers.size()); 5089716SN/A if (!respLayers[dest_port_id]->tryTiming(snoop_port)) { 50911744Snikos.nikoleris@arm.com DPRINTF(CoherentXBar, "%s: src %s packet %s BUSY\n", __func__, 51011744Snikos.nikoleris@arm.com snoop_port->name(), pkt->print()); 5119716SN/A return false; 5129716SN/A } 5138975SN/A } 5148975SN/A 51511744Snikos.nikoleris@arm.com DPRINTF(CoherentXBar, "%s: src %s packet %s\n", __func__, 51611744Snikos.nikoleris@arm.com src_port->name(), pkt->print()); 5178975SN/A 5189712SN/A // store size and command as they might be modified when 5199712SN/A // forwarding the packet 5209712SN/A unsigned int pkt_size = pkt->hasData() ? pkt->getSize() : 0; 5219712SN/A unsigned int pkt_cmd = pkt->cmdToIndex(); 5229712SN/A 5238975SN/A // responses are never express snoops 5248975SN/A assert(!pkt->isExpressSnoop()); 5258975SN/A 52610719SMarco.Balboni@ARM.com // a snoop response sees the snoop response latency, and if it is 52710719SMarco.Balboni@ARM.com // forwarded as a normal response, the response latency 52810719SMarco.Balboni@ARM.com Tick xbar_delay = 52910719SMarco.Balboni@ARM.com (forwardAsSnoop ? snoopResponseLatency : responseLatency) * 53010719SMarco.Balboni@ARM.com clockPeriod(); 53110719SMarco.Balboni@ARM.com 53210719SMarco.Balboni@ARM.com // set the packet header and payload delay 53310719SMarco.Balboni@ARM.com calcPacketTiming(pkt, xbar_delay); 53410719SMarco.Balboni@ARM.com 53510719SMarco.Balboni@ARM.com // determine how long to be crossbar layer is busy 53610719SMarco.Balboni@ARM.com Tick packetFinishTime = clockEdge(Cycles(1)) + pkt->payloadDelay; 5378975SN/A 5389714SN/A // forward it either as a snoop response or a normal response 5399714SN/A if (forwardAsSnoop) { 5409714SN/A // this is a snoop response to a snoop request we forwarded, 5419714SN/A // e.g. coming from the L1 and going to the L2, and it should 5429714SN/A // be forwarded as a snoop response 54310402SN/A 54410402SN/A if (snoopFilter) { 54510402SN/A // update the probe filter so that it can properly track the line 54610402SN/A snoopFilter->updateSnoopForward(pkt, *slavePorts[slave_port_id], 54710402SN/A *masterPorts[dest_port_id]); 54810402SN/A } 54910402SN/A 5509712SN/A bool success M5_VAR_USED = 5519712SN/A masterPorts[dest_port_id]->sendTimingSnoopResp(pkt); 5529712SN/A pktCount[slave_port_id][dest_port_id]++; 55310405Sandreas.hansson@arm.com pktSize[slave_port_id][dest_port_id] += pkt_size; 5548975SN/A assert(success); 5559714SN/A 5569715SN/A snoopLayers[dest_port_id]->succeededTiming(packetFinishTime); 5573244SN/A } else { 5588975SN/A // we got a snoop response on one of our slave ports, 55910405Sandreas.hansson@arm.com // i.e. from a coherent master connected to the crossbar, and 56010405Sandreas.hansson@arm.com // since we created the snoop request as part of recvTiming, 56110405Sandreas.hansson@arm.com // this should now be a normal response again 56210656Sandreas.hansson@arm.com outstandingSnoop.erase(pkt->req); 5638948SN/A 56410656Sandreas.hansson@arm.com // this is a snoop response from a coherent master, hence it 56510656Sandreas.hansson@arm.com // should never go back to where the snoop response came from, 56610656Sandreas.hansson@arm.com // but instead to where the original request came from 5679712SN/A assert(slave_port_id != dest_port_id); 5688948SN/A 56910402SN/A if (snoopFilter) { 57010402SN/A // update the probe filter so that it can properly track the line 57110402SN/A snoopFilter->updateSnoopResponse(pkt, *slavePorts[slave_port_id], 57210402SN/A *slavePorts[dest_port_id]); 57310402SN/A } 57410402SN/A 57511744Snikos.nikoleris@arm.com DPRINTF(CoherentXBar, "%s: src %s packet %s FWD RESP\n", __func__, 57611744Snikos.nikoleris@arm.com src_port->name(), pkt->print()); 57710402SN/A 5789714SN/A // as a normal response, it should go back to a master through 57910888Sandreas.hansson@arm.com // one of our slave ports, we also pay for any outstanding 58010888Sandreas.hansson@arm.com // header latency 58110888Sandreas.hansson@arm.com Tick latency = pkt->headerDelay; 58210888Sandreas.hansson@arm.com pkt->headerDelay = 0; 58310888Sandreas.hansson@arm.com slavePorts[dest_port_id]->schedTimingResp(pkt, curTick() + latency); 5849716SN/A 5859716SN/A respLayers[dest_port_id]->succeededTiming(packetFinishTime); 5863244SN/A } 5873244SN/A 58810656Sandreas.hansson@arm.com // remove the request from the routing table 58910656Sandreas.hansson@arm.com routeTo.erase(route_lookup); 59010656Sandreas.hansson@arm.com 5919712SN/A // stats updates 5929712SN/A transDist[pkt_cmd]++; 59310405Sandreas.hansson@arm.com snoops++; 59411564Sdavid.guillen@arm.com snoopTraffic += pkt_size; 5959712SN/A 5968948SN/A return true; 5978948SN/A} 5988948SN/A 5993210SN/A 6008948SN/Avoid 60110405Sandreas.hansson@arm.comCoherentXBar::forwardTiming(PacketPtr pkt, PortID exclude_slave_port_id, 60210888Sandreas.hansson@arm.com const std::vector<QueuedSlavePort*>& dests) 6038948SN/A{ 60411744Snikos.nikoleris@arm.com DPRINTF(CoherentXBar, "%s for %s\n", __func__, pkt->print()); 6059663SN/A 6069524SN/A // snoops should only happen if the system isn't bypassing caches 6079524SN/A assert(!system->bypassCaches()); 6089524SN/A 60910401SN/A unsigned fanout = 0; 61010401SN/A 61110405Sandreas.hansson@arm.com for (const auto& p: dests) { 6128948SN/A // we could have gotten this request from a snooping master 6138948SN/A // (corresponding to our own slave port that is also in 6148948SN/A // snoopPorts) and should not send it back to where it came 6158948SN/A // from 6169031SN/A if (exclude_slave_port_id == InvalidPortID || 6178948SN/A p->getId() != exclude_slave_port_id) { 6188948SN/A // cache is not allowed to refuse snoop 6198975SN/A p->sendTimingSnoopReq(pkt); 62010401SN/A fanout++; 6218948SN/A } 6228948SN/A } 62310401SN/A 62410401SN/A // Stats for fanout of this forward operation 62510401SN/A snoopFanout.sample(fanout); 6262497SN/A} 6272497SN/A 6289092SN/Avoid 62910713Sandreas.hansson@arm.comCoherentXBar::recvReqRetry(PortID master_port_id) 6309092SN/A{ 6319093SN/A // responses and snoop responses never block on forwarding them, 6329093SN/A // so the retry will always be coming from a port to which we 6339093SN/A // tried to forward a request 6349715SN/A reqLayers[master_port_id]->recvRetry(); 6359092SN/A} 6369092SN/A 6379036SN/ATick 63810405Sandreas.hansson@arm.comCoherentXBar::recvAtomic(PacketPtr pkt, PortID slave_port_id) 6392657SN/A{ 64011744Snikos.nikoleris@arm.com DPRINTF(CoherentXBar, "%s: src %s packet %s\n", __func__, 64111744Snikos.nikoleris@arm.com slavePorts[slave_port_id]->name(), pkt->print()); 6428915SN/A 64310405Sandreas.hansson@arm.com unsigned int pkt_size = pkt->hasData() ? pkt->getSize() : 0; 64410405Sandreas.hansson@arm.com unsigned int pkt_cmd = pkt->cmdToIndex(); 6459712SN/A 6468979SN/A MemCmd snoop_response_cmd = MemCmd::InvalidCmd; 6478979SN/A Tick snoop_response_latency = 0; 6488979SN/A 64912345Snikos.nikoleris@arm.com const bool snoop_caches = !system->bypassCaches() && 65012345Snikos.nikoleris@arm.com pkt->cmd != MemCmd::WriteClean; 65112345Snikos.nikoleris@arm.com if (snoop_caches) { 6528979SN/A // forward to all snoopers but the source 65310402SN/A std::pair<MemCmd, Tick> snoop_result; 65410402SN/A if (snoopFilter) { 65510402SN/A // check with the snoop filter where to forward this packet 65610402SN/A auto sf_res = 65710402SN/A snoopFilter->lookupRequest(pkt, *slavePorts[slave_port_id]); 65810402SN/A snoop_response_latency += sf_res.second * clockPeriod(); 65911744Snikos.nikoleris@arm.com DPRINTF(CoherentXBar, "%s: src %s packet %s SF size: %i lat: %i\n", 66011744Snikos.nikoleris@arm.com __func__, slavePorts[slave_port_id]->name(), pkt->print(), 66111744Snikos.nikoleris@arm.com sf_res.first.size(), sf_res.second); 66211130Sali.jafri@arm.com 66311130Sali.jafri@arm.com // let the snoop filter know about the success of the send 66411130Sali.jafri@arm.com // operation, and do it even before sending it onwards to 66511130Sali.jafri@arm.com // avoid situations where atomic upward snoops sneak in 66611130Sali.jafri@arm.com // between and change the filter state 66711605Snikos.nikoleris@arm.com snoopFilter->finishRequest(false, pkt->getAddr(), pkt->isSecure()); 66811130Sali.jafri@arm.com 66912241Snikos.nikoleris@arm.com if (pkt->isEviction()) { 67012241Snikos.nikoleris@arm.com // for block-evicting packets, i.e. writebacks and 67112241Snikos.nikoleris@arm.com // clean evictions, there is no need to snoop up, as 67212241Snikos.nikoleris@arm.com // all we do is determine if the block is cached or 67312241Snikos.nikoleris@arm.com // not, instead just set it here based on the snoop 67412241Snikos.nikoleris@arm.com // filter result 67512241Snikos.nikoleris@arm.com if (!sf_res.first.empty()) 67612241Snikos.nikoleris@arm.com pkt->setBlockCached(); 67712241Snikos.nikoleris@arm.com } else { 67812241Snikos.nikoleris@arm.com snoop_result = forwardAtomic(pkt, slave_port_id, InvalidPortID, 67912241Snikos.nikoleris@arm.com sf_res.first); 68012241Snikos.nikoleris@arm.com } 68110402SN/A } else { 68210402SN/A snoop_result = forwardAtomic(pkt, slave_port_id); 68310402SN/A } 6848979SN/A snoop_response_cmd = snoop_result.first; 68510402SN/A snoop_response_latency += snoop_result.second; 6868979SN/A } 6878915SN/A 68811334Sandreas.hansson@arm.com // set up a sensible default value 68911334Sandreas.hansson@arm.com Tick response_latency = 0; 69011334Sandreas.hansson@arm.com 69111334Sandreas.hansson@arm.com const bool sink_packet = sinkPacket(pkt); 69211130Sali.jafri@arm.com 6938948SN/A // even if we had a snoop response, we must continue and also 6948948SN/A // perform the actual request at the destination 69510405Sandreas.hansson@arm.com PortID master_port_id = findPort(pkt->getAddr()); 69610405Sandreas.hansson@arm.com 69711334Sandreas.hansson@arm.com if (sink_packet) { 69811744Snikos.nikoleris@arm.com DPRINTF(CoherentXBar, "%s: Not forwarding %s\n", __func__, 69911744Snikos.nikoleris@arm.com pkt->print()); 70011334Sandreas.hansson@arm.com } else { 70111334Sandreas.hansson@arm.com if (!pointOfCoherency || pkt->isRead() || pkt->isWrite()) { 70211334Sandreas.hansson@arm.com // forward the request to the appropriate destination 70311334Sandreas.hansson@arm.com response_latency = masterPorts[master_port_id]->sendAtomic(pkt); 70411334Sandreas.hansson@arm.com } else { 70511334Sandreas.hansson@arm.com // if it does not need a response we sink the packet above 70611334Sandreas.hansson@arm.com assert(pkt->needsResponse()); 70711334Sandreas.hansson@arm.com 70811334Sandreas.hansson@arm.com pkt->makeResponse(); 70911334Sandreas.hansson@arm.com } 71011334Sandreas.hansson@arm.com } 71111334Sandreas.hansson@arm.com 71210405Sandreas.hansson@arm.com // stats updates for the request 71310405Sandreas.hansson@arm.com pktCount[slave_port_id][master_port_id]++; 71410405Sandreas.hansson@arm.com pktSize[slave_port_id][master_port_id] += pkt_size; 71510405Sandreas.hansson@arm.com transDist[pkt_cmd]++; 7168948SN/A 7178948SN/A 71811130Sali.jafri@arm.com // if lower levels have replied, tell the snoop filter 71911130Sali.jafri@arm.com if (!system->bypassCaches() && snoopFilter && pkt->isResponse()) { 72010402SN/A snoopFilter->updateResponse(pkt, *slavePorts[slave_port_id]); 72110402SN/A } 72210402SN/A 7238948SN/A // if we got a response from a snooper, restore it here 7248948SN/A if (snoop_response_cmd != MemCmd::InvalidCmd) { 7258948SN/A // no one else should have responded 7268948SN/A assert(!pkt->isResponse()); 7278948SN/A pkt->cmd = snoop_response_cmd; 7288948SN/A response_latency = snoop_response_latency; 7298948SN/A } 7308948SN/A 7319712SN/A // add the response data 73210405Sandreas.hansson@arm.com if (pkt->isResponse()) { 73310405Sandreas.hansson@arm.com pkt_size = pkt->hasData() ? pkt->getSize() : 0; 73410405Sandreas.hansson@arm.com pkt_cmd = pkt->cmdToIndex(); 73510405Sandreas.hansson@arm.com 73610405Sandreas.hansson@arm.com // stats updates 73710405Sandreas.hansson@arm.com pktCount[slave_port_id][master_port_id]++; 73810405Sandreas.hansson@arm.com pktSize[slave_port_id][master_port_id] += pkt_size; 73910405Sandreas.hansson@arm.com transDist[pkt_cmd]++; 74010405Sandreas.hansson@arm.com } 7419712SN/A 74210694SMarco.Balboni@ARM.com // @todo: Not setting header time 74310694SMarco.Balboni@ARM.com pkt->payloadDelay = response_latency; 7448948SN/A return response_latency; 7458948SN/A} 7468948SN/A 7478948SN/ATick 74810405Sandreas.hansson@arm.comCoherentXBar::recvAtomicSnoop(PacketPtr pkt, PortID master_port_id) 7498948SN/A{ 75011744Snikos.nikoleris@arm.com DPRINTF(CoherentXBar, "%s: src %s packet %s\n", __func__, 75111744Snikos.nikoleris@arm.com masterPorts[master_port_id]->name(), pkt->print()); 7528948SN/A 7539712SN/A // add the request snoop data 75411564Sdavid.guillen@arm.com unsigned int pkt_size = pkt->hasData() ? pkt->getSize() : 0; 75510405Sandreas.hansson@arm.com snoops++; 75611564Sdavid.guillen@arm.com snoopTraffic += pkt_size; 7579712SN/A 7588948SN/A // forward to all snoopers 75910402SN/A std::pair<MemCmd, Tick> snoop_result; 76010402SN/A Tick snoop_response_latency = 0; 76110402SN/A if (snoopFilter) { 76210402SN/A auto sf_res = snoopFilter->lookupSnoop(pkt); 76310402SN/A snoop_response_latency += sf_res.second * clockPeriod(); 76411744Snikos.nikoleris@arm.com DPRINTF(CoherentXBar, "%s: src %s packet %s SF size: %i lat: %i\n", 76511744Snikos.nikoleris@arm.com __func__, masterPorts[master_port_id]->name(), pkt->print(), 76611744Snikos.nikoleris@arm.com sf_res.first.size(), sf_res.second); 76710402SN/A snoop_result = forwardAtomic(pkt, InvalidPortID, master_port_id, 76810402SN/A sf_res.first); 76910402SN/A } else { 77010402SN/A snoop_result = forwardAtomic(pkt, InvalidPortID); 77110402SN/A } 7728948SN/A MemCmd snoop_response_cmd = snoop_result.first; 77310402SN/A snoop_response_latency += snoop_result.second; 7748948SN/A 7758948SN/A if (snoop_response_cmd != MemCmd::InvalidCmd) 7768948SN/A pkt->cmd = snoop_response_cmd; 7778948SN/A 7789712SN/A // add the response snoop data 77910401SN/A if (pkt->isResponse()) { 78010405Sandreas.hansson@arm.com snoops++; 78110401SN/A } 7829712SN/A 78310694SMarco.Balboni@ARM.com // @todo: Not setting header time 78410694SMarco.Balboni@ARM.com pkt->payloadDelay = snoop_response_latency; 7858948SN/A return snoop_response_latency; 7868948SN/A} 7878948SN/A 7888948SN/Astd::pair<MemCmd, Tick> 78910405Sandreas.hansson@arm.comCoherentXBar::forwardAtomic(PacketPtr pkt, PortID exclude_slave_port_id, 79010402SN/A PortID source_master_port_id, 79110888Sandreas.hansson@arm.com const std::vector<QueuedSlavePort*>& dests) 7928948SN/A{ 7939032SN/A // the packet may be changed on snoops, record the original 7949032SN/A // command to enable us to restore it between snoops so that 7958948SN/A // additional snoops can take place properly 7964626SN/A MemCmd orig_cmd = pkt->cmd; 7974879SN/A MemCmd snoop_response_cmd = MemCmd::InvalidCmd; 7984879SN/A Tick snoop_response_latency = 0; 7993662SN/A 8009524SN/A // snoops should only happen if the system isn't bypassing caches 8019524SN/A assert(!system->bypassCaches()); 8029524SN/A 80310401SN/A unsigned fanout = 0; 80410401SN/A 80510405Sandreas.hansson@arm.com for (const auto& p: dests) { 8068915SN/A // we could have gotten this request from a snooping master 8078915SN/A // (corresponding to our own slave port that is also in 8088915SN/A // snoopPorts) and should not send it back to where it came 8098915SN/A // from 81010402SN/A if (exclude_slave_port_id != InvalidPortID && 81110402SN/A p->getId() == exclude_slave_port_id) 81210402SN/A continue; 81310401SN/A 81410402SN/A Tick latency = p->sendAtomicSnoop(pkt); 81510402SN/A fanout++; 81610402SN/A 81710402SN/A // in contrast to a functional access, we have to keep on 81810402SN/A // going as all snoopers must be updated even if we get a 81910402SN/A // response 82010402SN/A if (!pkt->isResponse()) 82110402SN/A continue; 82210402SN/A 82310402SN/A // response from snoop agent 82410402SN/A assert(pkt->cmd != orig_cmd); 82511284Sandreas.hansson@arm.com assert(pkt->cacheResponding()); 82610402SN/A // should only happen once 82710402SN/A assert(snoop_response_cmd == MemCmd::InvalidCmd); 82810402SN/A // save response state 82910402SN/A snoop_response_cmd = pkt->cmd; 83010402SN/A snoop_response_latency = latency; 83110402SN/A 83210402SN/A if (snoopFilter) { 83310402SN/A // Handle responses by the snoopers and differentiate between 83410402SN/A // responses to requests from above and snoops from below 83510402SN/A if (source_master_port_id != InvalidPortID) { 83610402SN/A // Getting a response for a snoop from below 83710402SN/A assert(exclude_slave_port_id == InvalidPortID); 83810402SN/A snoopFilter->updateSnoopForward(pkt, *p, 83910402SN/A *masterPorts[source_master_port_id]); 84010402SN/A } else { 84110402SN/A // Getting a response for a request from above 84210402SN/A assert(source_master_port_id == InvalidPortID); 84310402SN/A snoopFilter->updateSnoopResponse(pkt, *p, 84410402SN/A *slavePorts[exclude_slave_port_id]); 8454626SN/A } 8464626SN/A } 84710402SN/A // restore original packet state for remaining snoopers 84810402SN/A pkt->cmd = orig_cmd; 8494626SN/A } 8504626SN/A 85110401SN/A // Stats for fanout 85210401SN/A snoopFanout.sample(fanout); 85310401SN/A 8548948SN/A // the packet is restored as part of the loop and any potential 8558948SN/A // snoop response is part of the returned pair 8568948SN/A return std::make_pair(snoop_response_cmd, snoop_response_latency); 8572497SN/A} 8582497SN/A 8592497SN/Avoid 86010405Sandreas.hansson@arm.comCoherentXBar::recvFunctional(PacketPtr pkt, PortID slave_port_id) 8612497SN/A{ 8628663SN/A if (!pkt->isPrint()) { 8638663SN/A // don't do DPRINTFs on PrintReq as it clutters up the output 86411744Snikos.nikoleris@arm.com DPRINTF(CoherentXBar, "%s: src %s packet %s\n", __func__, 86511744Snikos.nikoleris@arm.com slavePorts[slave_port_id]->name(), pkt->print()); 8668663SN/A } 8678663SN/A 86810821Sandreas.hansson@arm.com if (!system->bypassCaches()) { 8698979SN/A // forward to all snoopers but the source 8709032SN/A forwardFunctional(pkt, slave_port_id); 8718979SN/A } 8724912SN/A 8738948SN/A // there is no need to continue if the snooping has found what we 8748948SN/A // were looking for and the packet is already a response 8758948SN/A if (!pkt->isResponse()) { 87610888Sandreas.hansson@arm.com // since our slave ports are queued ports we need to check them as well 87710888Sandreas.hansson@arm.com for (const auto& p : slavePorts) { 87810888Sandreas.hansson@arm.com // if we find a response that has the data, then the 87910888Sandreas.hansson@arm.com // downstream caches/memories may be out of date, so simply stop 88010888Sandreas.hansson@arm.com // here 88110888Sandreas.hansson@arm.com if (p->checkFunctional(pkt)) { 88210888Sandreas.hansson@arm.com if (pkt->needsResponse()) 88310888Sandreas.hansson@arm.com pkt->makeResponse(); 88410888Sandreas.hansson@arm.com return; 88510888Sandreas.hansson@arm.com } 88610888Sandreas.hansson@arm.com } 88710888Sandreas.hansson@arm.com 8889031SN/A PortID dest_id = findPort(pkt->getAddr()); 8898948SN/A 8908948SN/A masterPorts[dest_id]->sendFunctional(pkt); 8918948SN/A } 8928948SN/A} 8938948SN/A 8948948SN/Avoid 89510405Sandreas.hansson@arm.comCoherentXBar::recvFunctionalSnoop(PacketPtr pkt, PortID master_port_id) 8968948SN/A{ 8978948SN/A if (!pkt->isPrint()) { 8988948SN/A // don't do DPRINTFs on PrintReq as it clutters up the output 89911744Snikos.nikoleris@arm.com DPRINTF(CoherentXBar, "%s: src %s packet %s\n", __func__, 90011744Snikos.nikoleris@arm.com masterPorts[master_port_id]->name(), pkt->print()); 9018948SN/A } 9028948SN/A 90311188Sandreas.sandberg@arm.com for (const auto& p : slavePorts) { 90411188Sandreas.sandberg@arm.com if (p->checkFunctional(pkt)) { 90511188Sandreas.sandberg@arm.com if (pkt->needsResponse()) 90611188Sandreas.sandberg@arm.com pkt->makeResponse(); 90711188Sandreas.sandberg@arm.com return; 90811188Sandreas.sandberg@arm.com } 90911188Sandreas.sandberg@arm.com } 91011188Sandreas.sandberg@arm.com 9118948SN/A // forward to all snoopers 9129031SN/A forwardFunctional(pkt, InvalidPortID); 9138948SN/A} 9148948SN/A 9158948SN/Avoid 91610405Sandreas.hansson@arm.comCoherentXBar::forwardFunctional(PacketPtr pkt, PortID exclude_slave_port_id) 9178948SN/A{ 9189524SN/A // snoops should only happen if the system isn't bypassing caches 9199524SN/A assert(!system->bypassCaches()); 9209524SN/A 92110405Sandreas.hansson@arm.com for (const auto& p: snoopPorts) { 9228915SN/A // we could have gotten this request from a snooping master 9238915SN/A // (corresponding to our own slave port that is also in 9248915SN/A // snoopPorts) and should not send it back to where it came 9258915SN/A // from 9269031SN/A if (exclude_slave_port_id == InvalidPortID || 9278948SN/A p->getId() != exclude_slave_port_id) 9288948SN/A p->sendFunctionalSnoop(pkt); 9298915SN/A 9308948SN/A // if we get a response we are done 9318948SN/A if (pkt->isResponse()) { 9328948SN/A break; 9338915SN/A } 9343650SN/A } 9352497SN/A} 9362497SN/A 93711334Sandreas.hansson@arm.combool 93811334Sandreas.hansson@arm.comCoherentXBar::sinkPacket(const PacketPtr pkt) const 93911334Sandreas.hansson@arm.com{ 94011334Sandreas.hansson@arm.com // we can sink the packet if: 94111334Sandreas.hansson@arm.com // 1) the crossbar is the point of coherency, and a cache is 94211334Sandreas.hansson@arm.com // responding after being snooped 94311334Sandreas.hansson@arm.com // 2) the crossbar is the point of coherency, and the packet is a 94411334Sandreas.hansson@arm.com // coherency packet (not a read or a write) that does not 94511334Sandreas.hansson@arm.com // require a response 94611334Sandreas.hansson@arm.com // 3) this is a clean evict or clean writeback, but the packet is 94711334Sandreas.hansson@arm.com // found in a cache above this crossbar 94811334Sandreas.hansson@arm.com // 4) a cache is responding after being snooped, and the packet 94911334Sandreas.hansson@arm.com // either does not need the block to be writable, or the cache 95011334Sandreas.hansson@arm.com // that has promised to respond (setting the cache responding 95111334Sandreas.hansson@arm.com // flag) is providing writable and thus had a Modified block, 95211334Sandreas.hansson@arm.com // and no further action is needed 95311334Sandreas.hansson@arm.com return (pointOfCoherency && pkt->cacheResponding()) || 95411334Sandreas.hansson@arm.com (pointOfCoherency && !(pkt->isRead() || pkt->isWrite()) && 95511334Sandreas.hansson@arm.com !pkt->needsResponse()) || 95611334Sandreas.hansson@arm.com (pkt->isCleanEviction() && pkt->isBlockCached()) || 95711334Sandreas.hansson@arm.com (pkt->cacheResponding() && 95811334Sandreas.hansson@arm.com (!pkt->needsWritable() || pkt->responderHadWritable())); 95911334Sandreas.hansson@arm.com} 96011334Sandreas.hansson@arm.com 9619712SN/Avoid 96210405Sandreas.hansson@arm.comCoherentXBar::regStats() 9639712SN/A{ 96410405Sandreas.hansson@arm.com // register the stats of the base class and our layers 96510405Sandreas.hansson@arm.com BaseXBar::regStats(); 96610405Sandreas.hansson@arm.com for (auto l: reqLayers) 96710405Sandreas.hansson@arm.com l->regStats(); 96810405Sandreas.hansson@arm.com for (auto l: respLayers) 96910405Sandreas.hansson@arm.com l->regStats(); 97010405Sandreas.hansson@arm.com for (auto l: snoopLayers) 97110405Sandreas.hansson@arm.com l->regStats(); 9729712SN/A 97310405Sandreas.hansson@arm.com snoops 97410405Sandreas.hansson@arm.com .name(name() + ".snoops") 97510401SN/A .desc("Total snoops (count)") 97610401SN/A ; 97710401SN/A 97811564Sdavid.guillen@arm.com snoopTraffic 97911564Sdavid.guillen@arm.com .name(name() + ".snoopTraffic") 98011564Sdavid.guillen@arm.com .desc("Total snoop traffic (bytes)") 98111564Sdavid.guillen@arm.com ; 98211564Sdavid.guillen@arm.com 98310401SN/A snoopFanout 98410401SN/A .init(0, snoopPorts.size(), 1) 98510401SN/A .name(name() + ".snoop_fanout") 98610401SN/A .desc("Request fanout histogram") 98710401SN/A ; 9889712SN/A} 9899712SN/A 99010405Sandreas.hansson@arm.comCoherentXBar * 99110405Sandreas.hansson@arm.comCoherentXBarParams::create() 9922497SN/A{ 99310405Sandreas.hansson@arm.com return new CoherentXBar(this); 9942497SN/A} 995