Giacomo Travaglini has uploaded this change for review. (
https://gem5-review.googlesource.com/c/public/gem5/+/12358
Change subject: mem: Implement QoS Round Robin policy
......................................................................
mem: Implement QoS Round Robin policy
This patch is implementing a Round Robin policy. The policy
will get a non empty list of masters from the python world; when
it needs to schedule a packet, it checks the packet's MID with
the current active MID (in the rr algorithm) and choosing
LOW or HIGH priority accordingly.
Change-Id: I61abe5dafb1f724fed9e698a050ad509b56589ed
Signed-off-by: Giacomo Travaglini <giacomo.travagl...@arm.com>
---
M src/mem/qos/QoSPolicy.py
M src/mem/qos/SConscript
A src/mem/qos/policy_round_robin.cc
A src/mem/qos/policy_round_robin.hh
4 files changed, 241 insertions(+), 0 deletions(-)
diff --git a/src/mem/qos/QoSPolicy.py b/src/mem/qos/QoSPolicy.py
index 9ccd985..b69d5c2 100644
--- a/src/mem/qos/QoSPolicy.py
+++ b/src/mem/qos/QoSPolicy.py
@@ -81,3 +81,15 @@
# default fixed priority value for non-listed Masters
qos_fixed_prio_default_prio = Param.UInt8(0,
"Default priority for non-listed Masters")
+
+class QoSRoundRobinPolicy(QoSPolicy):
+ type = 'QoSRoundRobinPolicy'
+ cxx_header = "mem/qos/policy_round_robin.hh"
+ cxx_class = 'QoS::RoundRobinPolicy'
+
+ quantum_size = Param.UInt64(1,
+ "Quantum size: number of packets to be marked as high priority "
+ "before switching to the next MasterID")
+
+ qos_masters = VectorParam.String([],
+ "Policy will round robin over this set of masters")
diff --git a/src/mem/qos/SConscript b/src/mem/qos/SConscript
index 23351ca..fa22ae7 100644
--- a/src/mem/qos/SConscript
+++ b/src/mem/qos/SConscript
@@ -44,6 +44,7 @@
Source('policy.cc')
Source('policy_fixed_prio.cc')
+Source('policy_round_robin.cc')
Source('turnaround_policy_ideal.cc')
Source('q_policy.cc')
Source('mem_ctrl.cc')
diff --git a/src/mem/qos/policy_round_robin.cc
b/src/mem/qos/policy_round_robin.cc
new file mode 100644
index 0000000..0120791
--- /dev/null
+++ b/src/mem/qos/policy_round_robin.cc
@@ -0,0 +1,113 @@
+/*
+ * 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.
+ *
+ * Author: Giacomo Travaglini
+ */
+
+#include "mem/qos/policy_round_robin.hh"
+
+#include "mem/request.hh"
+
+namespace QoS {
+
+RoundRobinPolicy::RoundRobinPolicy(const Params* p)
+ : Policy(p), quantumSize(p->quantum_size), quantumCounter(0)
+{}
+
+RoundRobinPolicy::~RoundRobinPolicy()
+{}
+
+void
+RoundRobinPolicy::init()
+{
+ const auto& master_list = params()->qos_masters;
+ fatal_if(master_list.empty(),
+ "Empty master list in RoundRobin policy\n");
+
+ for (const auto& master : master_list) {
+ MasterID m_id = memCtrl->system()->lookupMasterId(master);
+
+ assert(m_id != Request::invldMasterId);
+ masters.insert(m_id);
+ }
+
+ selector = masters.begin();
+}
+
+void
+RoundRobinPolicy::advanceSelector()
+{
+ // If we only have 1 master (dummy case) we don't move the selector.
+ if (masters.size() > 1) {
+ if (quantumCounter >= quantumSize) {
+ selector++;
+ quantumCounter = 1;
+
+ // If we hit the end of the set, start from the first element
+ if (selector == masters.end()) {
+ selector = masters.begin();
+ }
+ } else {
+ quantumCounter++;
+ }
+ }
+}
+
+uint8_t
+RoundRobinPolicy::schedule(const MasterID pkt_mid, const uint64_t data)
+{
+ // advance the selector to point to the new masterID
+ advanceSelector();
+
+ MasterID curr_mid = *selector;
+
+ DPRINTF(QOS, "%s: Now serving Master %s (MasterID %d)\n", __func__,
+ memCtrl->system()->getMasterName(curr_mid), curr_mid);
+
+ if (pkt_mid == curr_mid) {
+ return HIGH;
+ } else {
+ return LOW;
+ }
+}
+
+} // namespace QoS
+
+QoS::RoundRobinPolicy *
+QoSRoundRobinPolicyParams::create()
+{
+ return new QoS::RoundRobinPolicy(this);
+}
diff --git a/src/mem/qos/policy_round_robin.hh
b/src/mem/qos/policy_round_robin.hh
new file mode 100644
index 0000000..c221ad8
--- /dev/null
+++ b/src/mem/qos/policy_round_robin.hh
@@ -0,0 +1,115 @@
+/*
+ * 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.
+ *
+ * Author: Giacomo Travaglini
+ */
+
+#ifndef __MEM_QOS_POLICY_ROUND_ROBIN_HH__
+#define __MEM_QOS_POLICY_ROUND_ROBIN_HH__
+
+#include "mem/qos/policy.hh"
+#include "params/QoSRoundRobinPolicy.hh"
+
+namespace QoS {
+
+/**
+ * Round Robin QoS Policy
+ *
+ * With this policy every master gets serviced with a round robin
+ * selection criteria. The policy rotates over a set of masters.
+ * When a packet needs to be scheduled, its masterID is compared
+ * with the current selected masterID and if it matches the packet
+ * receive high priority.
+ * After a specific number of packets (quantum), the policy's masterID
+ * moves to to the next one in the list.
+ */
+class RoundRobinPolicy : public Policy
+{
+ using Params = QoSRoundRobinPolicyParams;
+ const Params *params() const
+ { return static_cast<const Params *>(_params); }
+
+ /**
+ * In a round robin policy we only have two priorities:
+ * packets with low priority (0) and packets with high
+ * priority (the packets which are going to be served in
+ * the current quantum)
+ */
+ enum : uint8_t { LOW, HIGH };
+
+ public:
+ RoundRobinPolicy(const Params*);
+ virtual ~RoundRobinPolicy();
+
+ void init() override;
+
+ /**
+ * Schedules a packet based on round robin configuration
+ *
+ * @param m_id master id to schedule
+ * @param data data to schedule
+ * @return QoS priority value
+ */
+ virtual uint8_t schedule(const MasterID, const uint64_t) override;
+
+ protected:
+ /** Helper method used for advancing the selector */
+ void advanceSelector();
+
+ protected:
+ /**
+ * quantumSize represent the number of packets to be scheduled
+ * with high priority from a MasterID before switching
+ * to the next MasterID.
+ */
+ const uint64_t quantumSize;
+
+ /**
+ * quantumCounter gets incremented every time we try to schedule
+ * a packet. When quantumCounter == quantumSize it means we need
+ * to advance the selector and switch to the next MasterID, and
+ * the counter restarts from zero.
+ */
+ uint64_t quantumCounter;
+
+ std::set<MasterID>::iterator selector;
+
+ std::set<MasterID> masters;
+};
+
+} // namespace QoS
+
+#endif // __MEM_QOS_POLICY_ROUND_ROBIN_HH__
--
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Gerrit-Project: public/gem5
Gerrit-Branch: master
Gerrit-Change-Id: I61abe5dafb1f724fed9e698a050ad509b56589ed
Gerrit-Change-Number: 12358
Gerrit-PatchSet: 1
Gerrit-Owner: Giacomo Travaglini <giacomo.travagl...@arm.com>
Gerrit-MessageType: newchange
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