dev: add support for multi gem5 runs

Multi gem5 is an extension to gem5 to enable parallel simulation of a
distributed system (e.g. simulation of a pool of machines
connected by Ethernet links). A multi gem5 run consists of seperate gem5
processes running in parallel (potentially on different hosts/slots on
a cluster). Each gem5 process executes the simulation of a component of the
simulated distributed system (e.g. a multi-core board with an Ethernet NIC).

The patch implements the "distributed" Ethernet link device
(dev/src/multi_etherlink.[hh.cc]). This device will send/receive
(simulated) Ethernet packets to/from peer gem5 processes. The interface
to talk to the peer gem5 processes is defined in dev/src/multi_iface.hh and
in tcp_iface.hh.

There is also a central message server process (util/multi/tcp_server.[hh,cc])
which acts like an Ethernet switch and transfers messages among the gem5 peers.

A multi gem5 simulations can be kicked off by the util/multi/gem5-multi.sh
wrapper script.

Checkpoints are supported by multi-gem5. The checkpoint must be
initiated by a single gem5 process. E.g., the gem5 process with rank 0
can take a checkpoint from the bootscript just before it invokes
'mpirun' to launch an MPI test. The message server process will notify
all the other peer gem5 processes and make them take a checkpoint, too
(after completing a global synchronisation to ensure that there are no
inflight messages among gem5).

1 files changed, 100 insertions, 0 deletions

diff --git a/src/dev/multi_packet.cc b/src/dev/multi_packet.cc
new file mode 100644
index 000000000..1fd0c0e81
--- /dev/null
+++ b/src/dev/multi_packet.cc
@@ -0,0 +1,100 @@
+/*
+ * Copyright (c) 2015 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: Gabor Dozsa
+ */
+
+/* @file
+ * MultiHeaderPkt class to encapsulate multi-gem5 header packets
+ *
+ */
+
+#include "dev/multi_packet.hh"
+
+#include <cstdint>
+#include <cstring>
+
+#include "base/inet.hh"
+
+unsigned
+MultiHeaderPkt::maxAddressLength()
+{
+    return sizeof(AddressType);
+}
+
+void
+MultiHeaderPkt::clearAddress(AddressType &addr)
+{
+    std::memset(addr, 0, sizeof(addr));
+}
+
+bool
+MultiHeaderPkt::isAddressEqual(const AddressType &addr1,
+                               const AddressType &addr2)
+{
+    return (std::memcmp(addr1, addr2, sizeof(addr1)) == 0);
+}
+
+bool
+MultiHeaderPkt::isAddressLess(const AddressType &addr1,
+                              const AddressType &addr2)
+{
+    return (std::memcmp(addr1, addr2, sizeof(addr1)) < 0);
+}
+
+void
+MultiHeaderPkt::copyAddress(AddressType &dest, const AddressType &src)
+{
+    std::memcpy(dest, src, sizeof(dest));
+}
+
+bool
+MultiHeaderPkt::isBroadcastAddress(const AddressType &addr)
+{
+    return ((Net::EthAddr *)&addr)->broadcast();
+}
+
+bool
+MultiHeaderPkt::isMulticastAddress(const AddressType &addr)
+{
+    return ((Net::EthAddr *)&addr)->multicast();
+}
+
+bool
+MultiHeaderPkt::isUnicastAddress(const AddressType &addr)
+{
+    return ((Net::EthAddr *)&addr)->unicast();
+}