gem5/src/mem/ruby/network/simple/PerfectSwitch.cc
Nilay Vaish 5ffc165939 ruby: improved support for functional accesses
This patch adds support to different entities in the ruby memory system
for more reliable functional read/write accesses. Only the simple network
has been augmented as of now. Later on Garnet will also support functional
accesses.
The patch adds functional access code to all the different types of messages
that protocols can send around. These messages are functionally accessed
by going through the buffers maintained by the network entities.
The patch also rectifies some of the bugs found in coherence protocols while
testing the patch.

With this patch applied, functional writes always succeed. But functional
reads can still fail.
2012-10-15 17:51:57 -05:00

346 lines
12 KiB
C++

/*
* Copyright (c) 1999-2008 Mark D. Hill and David A. Wood
* All rights reserved.
*
* 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.
*/
#include <algorithm>
#include "base/cast.hh"
#include "debug/RubyNetwork.hh"
#include "mem/ruby/buffers/MessageBuffer.hh"
#include "mem/ruby/network/simple/PerfectSwitch.hh"
#include "mem/ruby/network/simple/SimpleNetwork.hh"
#include "mem/ruby/network/simple/Switch.hh"
#include "mem/ruby/slicc_interface/NetworkMessage.hh"
using namespace std;
const int PRIORITY_SWITCH_LIMIT = 128;
// Operator for helper class
bool
operator<(const LinkOrder& l1, const LinkOrder& l2)
{
return (l1.m_value < l2.m_value);
}
PerfectSwitch::PerfectSwitch(SwitchID sid, Switch *sw, uint32_t virt_nets)
: Consumer(sw)
{
m_switch_id = sid;
m_round_robin_start = 0;
m_wakeups_wo_switch = 0;
m_virtual_networks = virt_nets;
}
void
PerfectSwitch::init(SimpleNetwork *network_ptr)
{
m_network_ptr = network_ptr;
for(int i = 0;i < m_virtual_networks;++i)
{
m_pending_message_count.push_back(0);
}
}
void
PerfectSwitch::addInPort(const vector<MessageBuffer*>& in)
{
assert(in.size() == m_virtual_networks);
NodeID port = m_in.size();
m_in.push_back(in);
for (int j = 0; j < m_virtual_networks; j++) {
m_in[port][j]->setConsumer(this);
string desc = csprintf("[Queue from port %s %s %s to PerfectSwitch]",
to_string(m_switch_id), to_string(port), to_string(j));
m_in[port][j]->setDescription(desc);
m_in[port][j]->setIncomingLink(port);
m_in[port][j]->setVnet(j);
}
}
void
PerfectSwitch::addOutPort(const vector<MessageBuffer*>& out,
const NetDest& routing_table_entry)
{
assert(out.size() == m_virtual_networks);
// Setup link order
LinkOrder l;
l.m_value = 0;
l.m_link = m_out.size();
m_link_order.push_back(l);
// Add to routing table
m_out.push_back(out);
m_routing_table.push_back(routing_table_entry);
}
void
PerfectSwitch::clearRoutingTables()
{
m_routing_table.clear();
}
void
PerfectSwitch::clearBuffers()
{
for (int i = 0; i < m_in.size(); i++){
for(int vnet = 0; vnet < m_virtual_networks; vnet++) {
m_in[i][vnet]->clear();
}
}
for (int i = 0; i < m_out.size(); i++){
for(int vnet = 0; vnet < m_virtual_networks; vnet++) {
m_out[i][vnet]->clear();
}
}
}
void
PerfectSwitch::reconfigureOutPort(const NetDest& routing_table_entry)
{
m_routing_table.push_back(routing_table_entry);
}
PerfectSwitch::~PerfectSwitch()
{
}
void
PerfectSwitch::wakeup()
{
MsgPtr msg_ptr;
// Give the highest numbered link priority most of the time
m_wakeups_wo_switch++;
int highest_prio_vnet = m_virtual_networks-1;
int lowest_prio_vnet = 0;
int decrementer = 1;
NetworkMessage* net_msg_ptr = NULL;
// invert priorities to avoid starvation seen in the component network
if (m_wakeups_wo_switch > PRIORITY_SWITCH_LIMIT) {
m_wakeups_wo_switch = 0;
highest_prio_vnet = 0;
lowest_prio_vnet = m_virtual_networks-1;
decrementer = -1;
}
// For all components incoming queues
for (int vnet = highest_prio_vnet;
(vnet * decrementer) >= (decrementer * lowest_prio_vnet);
vnet -= decrementer) {
// This is for round-robin scheduling
int incoming = m_round_robin_start;
m_round_robin_start++;
if (m_round_robin_start >= m_in.size()) {
m_round_robin_start = 0;
}
if(m_pending_message_count[vnet] > 0) {
// for all input ports, use round robin scheduling
for (int counter = 0; counter < m_in.size(); counter++) {
// Round robin scheduling
incoming++;
if (incoming >= m_in.size()) {
incoming = 0;
}
// temporary vectors to store the routing results
vector<LinkID> output_links;
vector<NetDest> output_link_destinations;
// Is there a message waiting?
while (m_in[incoming][vnet]->isReady()) {
DPRINTF(RubyNetwork, "incoming: %d\n", incoming);
// Peek at message
msg_ptr = m_in[incoming][vnet]->peekMsgPtr();
net_msg_ptr = safe_cast<NetworkMessage*>(msg_ptr.get());
DPRINTF(RubyNetwork, "Message: %s\n", (*net_msg_ptr));
output_links.clear();
output_link_destinations.clear();
NetDest msg_dsts =
net_msg_ptr->getInternalDestination();
// Unfortunately, the token-protocol sends some
// zero-destination messages, so this assert isn't valid
// assert(msg_dsts.count() > 0);
assert(m_link_order.size() == m_routing_table.size());
assert(m_link_order.size() == m_out.size());
if (m_network_ptr->getAdaptiveRouting()) {
if (m_network_ptr->isVNetOrdered(vnet)) {
// Don't adaptively route
for (int out = 0; out < m_out.size(); out++) {
m_link_order[out].m_link = out;
m_link_order[out].m_value = 0;
}
} else {
// Find how clogged each link is
for (int out = 0; out < m_out.size(); out++) {
int out_queue_length = 0;
for (int v = 0; v < m_virtual_networks; v++) {
out_queue_length += m_out[out][v]->getSize();
}
int value =
(out_queue_length << 8) | (random() & 0xff);
m_link_order[out].m_link = out;
m_link_order[out].m_value = value;
}
// Look at the most empty link first
sort(m_link_order.begin(), m_link_order.end());
}
}
for (int i = 0; i < m_routing_table.size(); i++) {
// pick the next link to look at
int link = m_link_order[i].m_link;
NetDest dst = m_routing_table[link];
DPRINTF(RubyNetwork, "dst: %s\n", dst);
if (!msg_dsts.intersectionIsNotEmpty(dst))
continue;
// Remember what link we're using
output_links.push_back(link);
// Need to remember which destinations need this
// message in another vector. This Set is the
// intersection of the routing_table entry and the
// current destination set. The intersection must
// not be empty, since we are inside "if"
output_link_destinations.push_back(msg_dsts.AND(dst));
// Next, we update the msg_destination not to
// include those nodes that were already handled
// by this link
msg_dsts.removeNetDest(dst);
}
assert(msg_dsts.count() == 0);
//assert(output_links.size() > 0);
// Check for resources - for all outgoing queues
bool enough = true;
for (int i = 0; i < output_links.size(); i++) {
int outgoing = output_links[i];
if (!m_out[outgoing][vnet]->areNSlotsAvailable(1))
enough = false;
DPRINTF(RubyNetwork, "Checking if node is blocked ..."
"outgoing: %d, vnet: %d, enough: %d\n",
outgoing, vnet, enough);
}
// There were not enough resources
if (!enough) {
scheduleEvent(1);
DPRINTF(RubyNetwork, "Can't deliver message since a node "
"is blocked\n");
DPRINTF(RubyNetwork, "Message: %s\n", (*net_msg_ptr));
break; // go to next incoming port
}
MsgPtr unmodified_msg_ptr;
if (output_links.size() > 1) {
// If we are sending this message down more than
// one link (size>1), we need to make a copy of
// the message so each branch can have a different
// internal destination we need to create an
// unmodified MsgPtr because the MessageBuffer
// enqueue func will modify the message
// This magic line creates a private copy of the
// message
unmodified_msg_ptr = msg_ptr->clone();
}
// Enqueue it - for all outgoing queues
for (int i=0; i<output_links.size(); i++) {
int outgoing = output_links[i];
if (i > 0) {
// create a private copy of the unmodified
// message
msg_ptr = unmodified_msg_ptr->clone();
}
// Change the internal destination set of the
// message so it knows which destinations this
// link is responsible for.
net_msg_ptr = safe_cast<NetworkMessage*>(msg_ptr.get());
net_msg_ptr->getInternalDestination() =
output_link_destinations[i];
// Enqeue msg
DPRINTF(RubyNetwork, "Enqueuing net msg from "
"inport[%d][%d] to outport [%d][%d].\n",
incoming, vnet, outgoing, vnet);
m_out[outgoing][vnet]->enqueue(msg_ptr);
}
// Dequeue msg
m_in[incoming][vnet]->pop();
m_pending_message_count[vnet]--;
}
}
}
}
}
void
PerfectSwitch::storeEventInfo(int info)
{
m_pending_message_count[info]++;
}
void
PerfectSwitch::printStats(std::ostream& out) const
{
out << "PerfectSwitch printStats" << endl;
}
void
PerfectSwitch::clearStats()
{
}
void
PerfectSwitch::print(std::ostream& out) const
{
out << "[PerfectSwitch " << m_switch_id << "]";
}