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author | Andreas Sandberg <andreas.sandberg@arm.com> | 2018-05-02 13:55:10 +0100 |
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committer | Andreas Sandberg <andreas.sandberg@arm.com> | 2018-06-28 16:12:53 +0000 |
commit | 0f33b2c1d5875aae036a9e2779f6e9c764e0f85e (patch) | |
tree | 659285bb368acc6b5f93ef4ac52b1d3678a1a211 /src/mem/mem_delay.cc | |
parent | f6dd997ef43f52f80f5cdb43cd32614ce4169960 (diff) | |
download | gem5-0f33b2c1d5875aae036a9e2779f6e9c764e0f85e.tar.xz |
mem: Add a memory delay simulator
Add a memory system component that delays traffic. The base
functionality to delay packets is implemented in the abstract MemDelay
class. This class exposes three methods that control packet delays:
* delayReq(pkt)
* delayResp(pkt)
* delaySnoopResp(pkt)
These methods should be specialized to implement delays for specific
packet types.
The class SimpleMemDelay uses the MemDelay base class to implement
constant delays for read/write requests and responses.
The intention is that these classes can be used for rapid prototyping
of components that add a small fixed delay and the same throughput as
the interconnect. I.e., any buffering done in the base class will be
small and proportional to the introduced delay.
Change-Id: I158cb85f20e32bfdbcbfed66a785b4b2dd47b628
Signed-off-by: Andreas Sandberg <andreas.sandberg@arm.com>
Reviewed-by: Nicholas Lindsey <nicholas.lindsay@arm.com>
Reviewed-by: Nikos Nikoleris <nikos.nikoleris@arm.com>
Reviewed-on: https://gem5-review.googlesource.com/11521
Reviewed-by: Daniel Carvalho <odanrc@yahoo.com.br>
Reviewed-by: Jason Lowe-Power <jason@lowepower.com>
Maintainer: Nikos Nikoleris <nikos.nikoleris@arm.com>
Diffstat (limited to 'src/mem/mem_delay.cc')
-rw-r--r-- | src/mem/mem_delay.cc | 216 |
1 files changed, 216 insertions, 0 deletions
diff --git a/src/mem/mem_delay.cc b/src/mem/mem_delay.cc new file mode 100644 index 000000000..4a682f3bc --- /dev/null +++ b/src/mem/mem_delay.cc @@ -0,0 +1,216 @@ +/* + * Copyright (c) 2018 ARM Limited + * All rights reserved + * + * The license below extends only to copyright in the software and shall + * not be construed as granting a license to any other intellectual + * property including but not limited to intellectual property relating + * to a hardware implementation of the functionality of the software + * licensed hereunder. You may use the software subject to the license + * terms below provided that you ensure that this notice is replicated + * unmodified and in its entirety in all distributions of the software, + * modified or unmodified, in source code or in binary form. + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that the following conditions are + * met: redistributions of source code must retain the above copyright + * notice, this list of conditions and the following disclaimer; + * redistributions in binary form must reproduce the above copyright + * notice, this list of conditions and the following disclaimer in the + * documentation and/or other materials provided with the distribution; + * neither the name of the copyright holders nor the names of its + * contributors may be used to endorse or promote products derived from + * this software without specific prior written permission. + * + * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS + * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT + * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR + * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT + * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, + * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT + * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, + * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY + * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT + * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE + * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. + * + * Authors: Andreas Sandberg + */ + +#include "mem/mem_delay.hh" + +#include "params/MemDelay.hh" +#include "params/SimpleMemDelay.hh" + +MemDelay::MemDelay(const MemDelayParams *p) + : MemObject(p), + masterPort(name() + "-master", *this), + slavePort(name() + "-slave", *this), + reqQueue(*this, masterPort), + respQueue(*this, slavePort), + snoopRespQueue(*this, masterPort) +{ +} + +void +MemDelay::init() +{ + if (!slavePort.isConnected() || !masterPort.isConnected()) + fatal("Memory delay is not connected on both sides.\n"); +} + + +BaseMasterPort& +MemDelay::getMasterPort(const std::string& if_name, PortID idx) +{ + if (if_name == "master") { + return masterPort; + } else { + return MemObject::getMasterPort(if_name, idx); + } +} + +BaseSlavePort& +MemDelay::getSlavePort(const std::string& if_name, PortID idx) +{ + if (if_name == "slave") { + return slavePort; + } else { + return MemObject::getSlavePort(if_name, idx); + } +} + +bool +MemDelay::checkFunctional(PacketPtr pkt) +{ + return slavePort.checkFunctional(pkt) || + masterPort.checkFunctional(pkt); +} + +MemDelay::MasterPort::MasterPort(const std::string &_name, MemDelay &_parent) + : QueuedMasterPort(_name, &_parent, + _parent.reqQueue, _parent.snoopRespQueue), + parent(_parent) +{ +} + +bool +MemDelay::MasterPort::recvTimingResp(PacketPtr pkt) +{ + const Tick when = curTick() + parent.delayResp(pkt); + + parent.slavePort.schedTimingResp(pkt, when); + + return true; +} + +void +MemDelay::MasterPort::recvFunctionalSnoop(PacketPtr pkt) +{ + if (parent.checkFunctional(pkt)) { + pkt->makeResponse(); + } else { + parent.slavePort.sendFunctionalSnoop(pkt); + } +} + +Tick +MemDelay::MasterPort::recvAtomicSnoop(PacketPtr pkt) +{ + const Tick delay = parent.delaySnoopResp(pkt); + + return delay + parent.slavePort.sendAtomicSnoop(pkt); +} + +void +MemDelay::MasterPort::recvTimingSnoopReq(PacketPtr pkt) +{ + parent.slavePort.sendTimingSnoopReq(pkt); +} + + +MemDelay::SlavePort::SlavePort(const std::string &_name, MemDelay &_parent) + : QueuedSlavePort(_name, &_parent, _parent.respQueue), + parent(_parent) +{ +} + +Tick +MemDelay::SlavePort::recvAtomic(PacketPtr pkt) +{ + const Tick delay = parent.delayReq(pkt) + parent.delayResp(pkt); + + return delay + parent.masterPort.sendAtomic(pkt); +} + +bool +MemDelay::SlavePort::recvTimingReq(PacketPtr pkt) +{ + const Tick when = curTick() + parent.delayReq(pkt); + + parent.masterPort.schedTimingReq(pkt, when); + + return true; +} + +void +MemDelay::SlavePort::recvFunctional(PacketPtr pkt) +{ + if (parent.checkFunctional(pkt)) { + pkt->makeResponse(); + } else { + parent.masterPort.sendFunctional(pkt); + } +} + +bool +MemDelay::SlavePort::recvTimingSnoopResp(PacketPtr pkt) +{ + const Tick when = curTick() + parent.delaySnoopResp(pkt); + + parent.masterPort.schedTimingSnoopResp(pkt, when); + + return true; +} + + + +SimpleMemDelay::SimpleMemDelay(const SimpleMemDelayParams *p) + : MemDelay(p), + readReqDelay(p->read_req), + readRespDelay(p->read_resp), + writeReqDelay(p->write_req), + writeRespDelay(p->write_resp) +{ +} + +Tick +SimpleMemDelay::delayReq(PacketPtr pkt) +{ + if (pkt->isRead()) { + return readReqDelay; + } else if (pkt->isWrite()) { + return writeReqDelay; + } else { + return 0; + } +} + +Tick +SimpleMemDelay::delayResp(PacketPtr pkt) +{ + if (pkt->isRead()) { + return readRespDelay; + } else if (pkt->isWrite()) { + return writeRespDelay; + } else { + return 0; + } +} + + +SimpleMemDelay * +SimpleMemDelayParams::create() +{ + return new SimpleMemDelay(this); +} |