add testcase for mixed mode (#20)

* add testcase for mixed mode

* add server load

* fix log

tests/test_ipc_benchmark.cc

@@ -142,6 +142,30 @@ void push_pull(KVWorker<char> &kv,
   }
 }
 
+int AllocateServer(int seed, int total_key_num) {
+  bool mixed_mode = Environment::Get()->find("BYTEPS_ENABLE_MIXED_MODE") 
+                    ? atoi(Environment::Get()->find("BYTEPS_ENABLE_MIXED_MODE")) 
+                    : false;
+  const int num_server_total = ps::Postoffice::Get()->GetServerKeyRanges().size();
+  const int num_worker_total = ps::Postoffice::Get()->num_workers();
+  auto num_server_noncolocate = num_server_total - num_worker_total;
+  auto num_server_colocate = num_worker_total;
+
+  if (!mixed_mode) {
+    return seed % num_server_total;
+  }
+
+  // below we assume the seed increases from 0 with step size 1
+  auto ratio = (2.0 * num_server_noncolocate * (num_worker_total - 1)) / 
+      ((num_worker_total) * (num_worker_total + num_server_noncolocate) - 2 * num_server_noncolocate);
+  auto threshold = ratio * total_key_num;
+  if (seed < threshold) {
+    return seed % num_server_noncolocate;
+  } else {
+    return num_server_noncolocate + (seed % num_server_colocate);
+  }
+}
+
 void RunWorker(int argc, char *argv[]) {
   if (!IsWorker()) return;
   KVWorker<char> kv(0, 0);
@@ -162,7 +186,7 @@ void RunWorker(int argc, char *argv[]) {
       << ", try reduce tensor size or increase BYTEPS_PARTITION_BYTES";
 
   auto v = Environment::Get()->find("NUM_KEY_PER_SERVER");
-  const int how_many_key_per_server = v ? atoi(v) : 20;
+  const int how_many_key_per_server = v ? atoi(v) : 10;
   const int total_key_num = num_servers * how_many_key_per_server;
 
   std::vector<SArray<char> > server_vals;
@@ -176,9 +200,12 @@ void RunWorker(int argc, char *argv[]) {
     server_vals.push_back(vals);
   }
 
+  std::unordered_map<int, size_t> accumulated_key_num;
   // init push, do not count this into time cost
   for (int i = 0; i < total_key_num; i++) {
-    int server = i % num_servers;
+    int server = AllocateServer(i, total_key_num);
+    accumulated_key_num[server] += 1;
+
     auto vals = server_vals[i];
 
     auto key = EncodeKey(i);
@@ -206,6 +233,12 @@ void RunWorker(int argc, char *argv[]) {
     kv.Wait(kv.ZPush(keys, vals, lens));
   }
 
+  for (int i = 0; i < num_servers; ++i) {
+    PS_VLOG(1) << "server-" << i 
+        << " load is " << (100.0 * accumulated_key_num[i] / total_key_num)
+        << "%";
+  }
+
   push_pull(kv, server_keys, server_vals, server_lens, len, num_servers, total_key_num, how_many_key_per_server, mode);
 }