From 61c3439b7ff12b824ffe4460eac31e7ef0489c49 Mon Sep 17 00:00:00 2001
From: Jan Huwald <jh@sotun.de>
Date: Thu, 28 Feb 2013 10:18:56 +0100
Subject: get memory via mmap, try huge tables and prepopulation


diff --git a/cacount.cpp b/cacount.cpp
index 210d9b8..bd8f1a6 100644
--- a/cacount.cpp
+++ b/cacount.cpp
@@ -9,6 +9,8 @@
 #include <map>
 #include <set>
 
+#include <sys/mman.h>
+
 using namespace std;
 
 typedef uint32_t State;
@@ -48,19 +50,17 @@ void init(Trans &t) {
       t[s] = update(s); });
 }
 
-Trans* findCycle(Trans &t) {
+void findCycle(Trans &t, Trans &c) {
   // forward to t=maxState; now every state is in a cycle
   iterTrans(logState, [&](int s) {
       t[s] = t[t[s]]; }, true);
   // compute loop id (lowest occuring state no): go through the loop again and
   // record the lowest occuring state number
-  Trans &c(*new Trans());
   iterState([&](int s) { 
       c[s] = t[s]; });
   iterTrans(logState, [&](int s) {
       c[s] = min(c[s], c[t[s]]);
       t[s] = t[t[s]]; }, true);
-  return &c;
 }
 
 void cycleStat(Trans &c) {
@@ -120,6 +120,16 @@ void printTraj(State s, int count) {
   }
 }
 
+template<typename T>
+T* mmalloc() {
+  void *p = MAP_FAILED;
+  for (auto flag : {MAP_POPULATE | MAP_HUGETLB, MAP_POPULATE, 0})
+    if (p == MAP_FAILED)
+      p = mmap(NULL, sizeof(Trans), PROT_READ | PROT_WRITE, MAP_PRIVATE | MAP_ANONYMOUS | flag, -1, 0);
+  assert(p != MAP_FAILED);
+  return (T*) p;
+}
+
 int main(int argc, char **argv) {
   assert(argc >= 2);
   rule = atoi(argv[1]);
@@ -128,10 +138,11 @@ int main(int argc, char **argv) {
     printTraj(atoi(argv[3]), atoi(argv[4]));
   }
   if (!strcmp(argv[2], "cycle")) {
-    Trans &t = *(new Trans);
-    init(t);
-    Trans &c(*findCycle(t));
-    cycleStat(c);
+    Trans *t = mmalloc<Trans>(),
+      *c = mmalloc<Trans>();
+    init(*t);
+    findCycle(*t, *c);
+    cycleStat(*c);
   }
   return 0;
 }
-- 
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