Changeset 646

Timestamp:

03/31/06 08:46:58 (6 years ago)

Author:

ahu

Message:

implement very simple cache cache that catches repeated nearly identical lookups
appears to have lowered cpu load by 40%

Location:

trunk/pdns/pdns

Files:

• recursor_cache.cc (modified) (3 diffs)
• recursor_cache.hh (modified) (2 diffs)

trunk/pdns/pdns/recursor_cache.cc

@@ -79 +79 @@
 {
   unsigned int ttd=0;
-  tuple<string, uint16_t> key=make_tuple(toLowerCanonic(qname), qt.getCode());
-
-  cache_t::const_iterator j=d_cache.find(key);
-
-  //  cerr<<"looking up "<< toLowerCanonic(qname)+"|"+qt.getName() << " ("<<key<<", "<<code<<")\n";
+  string lqname(toLowerCanonic(qname));
+
+  //  cerr<<"looking up "<< toLowerCanonic(qname)+"|"+qt.getName()<<"\n";
+
+  if(!d_cachecachevalid || d_cachedqname != lqname) {
+    //    cerr<<"had cache cache miss"<<endl;
+    d_cachedqname=lqname;
+    d_cachecache=d_cache.equal_range(tie(lqname));
+    d_cachecachevalid=true;
+  }
+  else
+    ;
+  //    cerr<<"had cache cache hit!"<<endl;
+
+
   if(res)
     res->clear();
 
-  if(j!=d_cache.end()) { 
+  if(d_cachecache.first!=d_cachecache.second) { 
     if(res) {
-      for(vector<StoredRecord>::const_iterator k=j->d_records.begin(); k != j->d_records.end(); ++k) {
-        if(k->d_ttd > (uint32_t) now) {
-          DNSResourceRecord rr=String2DNSRR(qname, qt,  k->d_string, ttd=k->d_ttd); 
-          res->insert(rr);
-        }
-      }
+      for(cache_t::const_iterator i=d_cachecache.first; i != d_cachecache.second; ++i) 
+        if(i->d_qtype == qt.getCode()) 
+          for(vector<StoredRecord>::const_iterator k=i->d_records.begin(); k != i->d_records.end(); ++k) {
+            if(k->d_ttd > (uint32_t) now) {
+              DNSResourceRecord rr=String2DNSRR(qname, qt,  k->d_string, ttd=k->d_ttd); 
+              res->insert(rr);
+            }
+          }
     }
 
@@ -109 +121 @@
 void MemRecursorCache::replace(const string &qname, const QType& qt,  const set<DNSResourceRecord>& content)
 {
+  d_cachecachevalid=false;
   tuple<string, uint16_t> key=make_tuple(toLowerCanonic(qname), qt.getCode());
   cache_t::iterator stored=d_cache.find(key);
@@ -180 +193 @@
 {
   uint32_t now=(uint32_t)time(0);
-
+  d_cachecachevalid=false;
 //  cout<<"Going to prune!\n";
 

trunk/pdns/pdns/recursor_cache.hh

@@ -25 +25 @@
 {
 public:
+  MemRecursorCache() : d_cachecachevalid(false)
+  {}
   unsigned int size();
   unsigned int bytes();
@@ -107 +109 @@
 private:
   cache_t d_cache;
-
+  pair<cache_t::const_iterator, cache_t::const_iterator> d_cachecache;
+  string d_cachedqname;
+  bool d_cachecachevalid;
 };