From c2a1e3a668f9a88239184e13460f7e1725b15c90 Mon Sep 17 00:00:00 2001
From: Mahmoud <abdallm@purdue.edu>
Date: Mon, 26 Aug 2019 12:17:52 -0400
Subject: Banked L1, adding iSLIP and RR arbiteratio and adding some comments

---
 src/gpgpu-sim/local_interconnect.cc | 40 ++++++++++++++++++++++++++++---------
 1 file changed, 31 insertions(+), 9 deletions(-)

(limited to 'src/gpgpu-sim/local_interconnect.cc')

diff --git a/src/gpgpu-sim/local_interconnect.cc b/src/gpgpu-sim/local_interconnect.cc
index 1416b2c..da8a65c 100644
--- a/src/gpgpu-sim/local_interconnect.cc
+++ b/src/gpgpu-sim/local_interconnect.cc
@@ -36,7 +36,7 @@
 #include "local_interconnect.h"
 #include "mem_fetch.h"
 
-xbar_router::xbar_router(unsigned router_id, enum Interconnect_type m_type, unsigned n_shader, unsigned n_mem, unsigned m_in_buffer_limit, unsigned m_out_buffer_limit)
+xbar_router::xbar_router(unsigned router_id, enum Interconnect_type m_type, unsigned n_shader, unsigned n_mem, unsigned m_in_buffer_limit, unsigned m_out_buffer_limit, enum Arbiteration_type m_arbit_type)
 {
 	m_id=router_id;
 	router_type=m_type;
@@ -46,9 +46,10 @@ xbar_router::xbar_router(unsigned router_id, enum Interconnect_type m_type, unsi
 	in_buffers.resize(total_nodes);
 	out_buffers.resize(total_nodes);
 	next_node.resize(total_nodes,0);
-//	next_node = 0;
 	in_buffer_limit = m_in_buffer_limit;
 	out_buffer_limit = m_out_buffer_limit;
+	arbit_type = m_arbit_type;
+	next_node_id=0;
 	if(m_type == REQ_NET) {
 		active_in_buffers=n_shader;
 		active_out_buffers=n_mem;
@@ -109,14 +110,25 @@ bool xbar_router::Has_Buffer_In(unsigned input_deviceID, unsigned size, bool upd
 bool xbar_router::Has_Buffer_Out(unsigned output_deviceID, unsigned size){
 	return (out_buffers[output_deviceID].size() + size <= out_buffer_limit);
 }
-/*
+
 void xbar_router::Advance() {
+
+	if(arbit_type == NAIVE_RR)
+		RR_Advance();
+	else if(arbit_type == iSLIP)
+		iSLIP_Advance();
+	else
+		assert(0);
+
+}
+
+void xbar_router::RR_Advance() {
 	cycles++;
 
 	vector<bool> issued(total_nodes, false);
 
 	for(unsigned i=0; i<total_nodes; ++i){
-		unsigned node_id = (i+next_node)%total_nodes;
+		unsigned node_id = (i+next_node_id)%total_nodes;
 
 		if(!in_buffers[node_id].empty()) {
 			Packet _packet = in_buffers[node_id].front();
@@ -130,12 +142,16 @@ void xbar_router::Advance() {
 				else
 					conflicts++;
 			}
-			else
+			else {
 				out_buffer_full++;
+
+				if(issued[_packet.output_deviceID])
+					conflicts++;
+			}
 		}
 	}
 
-	next_node = (++next_node % total_nodes);
+	next_node_id = (++next_node_id % total_nodes);
 
 	//collect some stats about buffer util
 	for(unsigned i=0; i<total_nodes; ++i){
@@ -143,13 +159,17 @@ void xbar_router::Advance() {
 		out_buffer_util+=out_buffers[i].size();
 	}
 }
-*/
 
-void xbar_router::Advance() {
+//iSLIP algorithm
+//McKeown, Nick. "The iSLIP scheduling algorithm for input-queued switches." IEEE/ACM transactions on networking 2 (1999): 188-201.
+//https://www.cs.rutgers.edu/~sn624/552-F18/papers/islip.pdf
+void xbar_router::iSLIP_Advance() {
 	cycles++;
 
 	vector<unsigned> node_tmp;
 
+
+	//calcaulte how many conflicts are there for stats
 	for (unsigned i=0; i<total_nodes; ++i){
 		
 		if(!in_buffers[i].empty()){
@@ -167,6 +187,8 @@ void xbar_router::Advance() {
 		}
 	}
 
+
+	//do iSLIP
 	for(unsigned i=0; i<total_nodes; ++i){
 
 		if(Has_Buffer_Out(i, 1)) {
@@ -242,7 +264,7 @@ void LocalInterconnect::CreateInterconnect(unsigned m_n_shader, unsigned m_n_mem
 
 	net.resize(n_subnets);
 	for (unsigned i = 0; i < n_subnets; ++i) {
-		net[i] = new xbar_router( i, static_cast<Interconnect_type>(i), m_n_shader, m_n_mem, m_inct_config.in_buffer_limit, m_inct_config.out_buffer_limit );
+		net[i] = new xbar_router( i, static_cast<Interconnect_type>(i), m_n_shader, m_n_mem, m_inct_config.in_buffer_limit, m_inct_config.out_buffer_limit,m_inct_config.arbiter_algo);
 	}
 
 }
-- 
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