Add -seed to the Dragonfly/SlimFly UEC binaries and use a separate RNG seed for each switch

htsim/sim/datacenter/dragonfly_switch.cpp

@@ -7,6 +7,7 @@
 
 bool DragonflySwitch::_trim_disable = false;
 uint16_t DragonflySwitch::_trim_size = 0;
+int64_t DragonflySwitch::_rng_seed = -1;
 DragonflySwitch::RoutingStrategy DragonflySwitch::_routing_strategy = DragonflySwitch::MINIMAL;
 
 string ntoa(double n);
@@ -30,7 +31,12 @@ DragonflySwitch::DragonflySwitch(EventList& event_list,
 
     _pipe = new CallbackPipe(delay, event_list, this);
 
-    _generator = std::mt19937(33);
+    if (_rng_seed < 0) {
+        _generator = std::mt19937(33);
+    } else {
+        std::seed_seq seq{(uint32_t)_rng_seed, (uint32_t)_id};
+        _generator = std::mt19937(seq);
+    }
     _dist_a = std::uniform_int_distribution<>(0, _a - 1);
     _dist_h = std::uniform_int_distribution<>(0, _h - 1);
 

htsim/sim/datacenter/dragonfly_switch.h

@@ -37,6 +37,8 @@ class DragonflySwitch : public Switch {
     }
     static uint16_t get_trim_disable() { return _trim_disable; }
     static uint16_t get_trim_size() { return _trim_size; }
+    // -1 keeps the legacy behaviour (every switch seeded with 33).
+    static void set_rng_seed(int64_t seed) { _rng_seed = seed; }
 
 private:
     SwitchType _type;
@@ -70,6 +72,7 @@ class DragonflySwitch : public Switch {
     static bool _trim_disable;
     static uint16_t _trim_size;
     static RoutingStrategy _routing_strategy;
+    static int64_t _rng_seed;
 };
 
 #endif

htsim/sim/datacenter/main_uec_df.cpp

@@ -32,6 +32,7 @@ int main(int argc, char** argv) {
     Clock c(timeFromSec(5 / 100.), eventlist);
 
     int seed = 13;
+    bool seed_set = false;
     srand(seed);
     srandom(seed);
 
@@ -163,6 +164,10 @@ int main(int argc, char** argv) {
             else
                 throw std::logic_error("LB not recognized");
             i++;
+        } else if (!strcmp(argv[i], "-seed")) {
+            seed = std::stoi(argv[i + 1]);
+            seed_set = true;
+            i++;
         } else if (!strcmp(argv[i], "-paths")) {
             path_entropy_size = std::stoi(argv[i + 1]);
             i++;
@@ -280,6 +285,12 @@ int main(int argc, char** argv) {
     }
 
     // Topology
+    if (seed_set) {
+        srand(seed);
+        srandom(seed);
+        DragonflySwitch::set_rng_seed(seed);
+        std::cout << "Random seed " << seed << std::endl;
+    }
     DragonflySwitch::set_config(routing_strategy, trim_disable, trim_size);
     DragonflyTopology* topo = new DragonflyTopology(qt, queuesize, qlf, &eventlist);
     topo->load_topology(topo_base_path);

htsim/sim/datacenter/main_uec_sf.cpp

@@ -32,6 +32,7 @@ int main(int argc, char** argv) {
     Clock c(timeFromSec(5 / 100.), eventlist);
 
     int seed = 13;
+    bool seed_set = false;
     srand(seed);
     srandom(seed);
 
@@ -165,6 +166,10 @@ int main(int argc, char** argv) {
             else
                 throw std::logic_error("LB not recognized");
             i++;
+        } else if (!strcmp(argv[i], "-seed")) {
+            seed = std::stoi(argv[i + 1]);
+            seed_set = true;
+            i++;
         } else if (!strcmp(argv[i], "-paths")) {
             path_entropy_size = std::stoi(argv[i + 1]);
             i++;
@@ -282,6 +287,12 @@ int main(int argc, char** argv) {
     }
 
     // Topology
+    if (seed_set) {
+        srand(seed);
+        srandom(seed);
+        SlimFlySwitch::set_rng_seed(seed);
+        std::cout << "Random seed " << seed << std::endl;
+    }
     SlimFlySwitch::set_config(routing_strategy, trim_disable, trim_size);
     SlimFlyTopology* topo = new SlimFlyTopology(topo_base_path, qt, queuesize, qlf, &eventlist);
     topo->load_topology(topo_base_path);

htsim/sim/datacenter/slimfly_switch.cpp

@@ -9,6 +9,7 @@ extern void tokenize(std::string const& str, const char delim, std::vector<std::
 
 bool SlimFlySwitch::_trim_disable = false;
 uint16_t SlimFlySwitch::_trim_size = 0;
+int64_t SlimFlySwitch::_rng_seed = -1;
 SlimFlySwitch::RoutingStrategy SlimFlySwitch::_routing_strategy = SlimFlySwitch::MINIMAL;
 
 string ntoa(double n);
@@ -37,7 +38,12 @@ SlimFlySwitch::SlimFlySwitch(std::string path_fib,
 
 void SlimFlySwitch::init_neighbours() {
     _neighbours = _topo->get_neighbours(_id);
-    _generator = mt19937(33);
+    if (_rng_seed < 0) {
+        _generator = std::mt19937(33);
+    } else {
+        std::seed_seq seq{(uint32_t)_rng_seed, (uint32_t)_id};
+        _generator = std::mt19937(seq);
+    }
     _dist_neighbour = uniform_int_distribution<>(0, _neighbours->size() - 1);
 }
 

htsim/sim/datacenter/slimfly_switch.h

@@ -42,6 +42,8 @@ class SlimFlySwitch : public Switch {
     }
     static uint16_t get_trim_disable() { return _trim_disable; }
     static uint16_t get_trim_size() { return _trim_size; }
+    // -1 keeps the legacy behaviour (every switch seeded with 33).
+    static void set_rng_seed(int64_t seed) { _rng_seed = seed; }
 
 private:
     std::string _path_fib;
@@ -71,6 +73,7 @@ class SlimFlySwitch : public Switch {
     static bool _trim_disable;
     static uint16_t _trim_size;
     static RoutingStrategy _routing_strategy;
+    static int64_t _rng_seed;
 };
 
 #endif