ruby: replace g_ruby_start with per-RubySystem m_start_cycle

This patch begins the process of removing global variables from the Ruby
source with the goal of eventually allowing users to create multiple Ruby
instances in a single simulation.  Currently, users cannot do so because
several global variables and static members are referenced by the RubySystem
object in a way that assumes that there will only ever be a single RubySystem.
These need to be replaced with per-RubySystem equivalents.

This specific patch replaces the global var g_ruby_start, which is used
to calculate throughput statistics for Throttles in simple networks and
links in Garnet networks, with a RubySystem instance var m_start_cycle.

1 files changed, 8 insertions, 6 deletions

diff --git a/src/mem/ruby/network/simple/Throttle.cc b/src/mem/ruby/network/simple/Throttle.cc
index d722c91ea..f0cd6bd16 100644
--- a/src/mem/ruby/network/simple/Throttle.cc
+++ b/src/mem/ruby/network/simple/Throttle.cc
@@ -46,19 +46,19 @@ const int PRIORITY_SWITCH_LIMIT = 128;
 
 static int network_message_to_size(Message* net_msg_ptr);
 
-Throttle::Throttle(int sID, NodeID node, Cycles link_latency,
+Throttle::Throttle(int sID, RubySystem *rs, NodeID node, Cycles link_latency,
                    int link_bandwidth_multiplier, int endpoint_bandwidth,
                    ClockedObject *em)
-    : Consumer(em)
+    : Consumer(em), m_ruby_system(rs)
 {
     init(node, link_latency, link_bandwidth_multiplier, endpoint_bandwidth);
     m_sID = sID;
 }
 
-Throttle::Throttle(NodeID node, Cycles link_latency,
+Throttle::Throttle(RubySystem *rs, NodeID node, Cycles link_latency,
                    int link_bandwidth_multiplier, int endpoint_bandwidth,
                    ClockedObject *em)
-    : Consumer(em)
+    : Consumer(em), m_ruby_system(rs)
 {
     init(node, link_latency, link_bandwidth_multiplier, endpoint_bandwidth);
     m_sID = 0;
@@ -245,8 +245,10 @@ Throttle::clearStats()
 void
 Throttle::collateStats()
 {
-    m_link_utilization = 100.0 * m_link_utilization_proxy
-        / (double(g_system_ptr->curCycle() - g_ruby_start));
+    double time_delta = double(m_ruby_system->curCycle() -
+                               m_ruby_system->getStartCycle());
+
+    m_link_utilization = 100.0 * m_link_utilization_proxy / time_delta;
 }
 
 void