Changeset 1399 for trunk/pdns/pdns/packetcache.cc

Timestamp:

08/22/09 21:20:17 (4 years ago)

Author:

ahu

Message:

repair cache cleaning logic, which would never run in certain benchmark situations, plus retune the actual cleaning process.
Thanks to Marcus Goller for reporting this issue.

Files:

• trunk/pdns/pdns/packetcache.cc (modified) (12 diffs)

trunk/pdns/pdns/packetcache.cc

@@ -29 +29 @@
 {
   pthread_rwlock_init(&d_mut,0);
-  d_hit=d_miss=0;
+  d_ops = 0;
 
   d_ttl=-1;
@@ -51 +51 @@
 {
   extern StatBag S;
-  if(!((d_hit+d_miss)%150000)) {
-    cleanup();
-  }
 
   if(d_ttl<0) 
     getTTLS();
+
+  if(!((d_ops++) % 300000)) {
+    cleanup();
+  }
+
 
   if(d_doRecursion && p->d.rd) { // wants recursion
     if(!d_recursivettl) {
       (*d_statnummiss)++;
-      d_miss++;
       return 0;
     }
@@ -68 +69 @@
     if(!d_ttl) {
       (*d_statnummiss)++;
-      d_miss++;
       return 0;
     }
@@ -86 +86 @@
     }
 
-    if(!((d_hit+d_miss)%30000)) {
-      *d_statnumentries=d_map.size(); // needs lock
-    }
-    haveSomething=getEntry(p->qdomain, p->qtype, PacketCache::PACKETCACHE, value, -1, packetMeritsRecursion);
+    haveSomething=getEntryLocked(p->qdomain, p->qtype, PacketCache::PACKETCACHE, value, -1, packetMeritsRecursion);
   }
   if(haveSomething) {
     (*d_statnumhit)++;
-    d_hit++;
     if(cached->noparse(value.c_str(), value.size()) < 0) {
       return 0;
@@ -103 +99 @@
   //  cerr<<"Packet cache miss for '"<<p->qdomain<<"', merits: "<<packetMeritsRecursion<<endl;
   (*d_statnummiss)++;
-  d_miss++;
   return 0; // bummer
 }
@@ -133 +128 @@
 void PacketCache::insert(const string &qname, const QType& qtype, CacheEntryType cet, const string& value, unsigned int ttl, int zoneID, bool meritsRecursion)
 {
+  if(!((d_ops++) % 300000)) {
+    cleanup();
+  }
+
   if(!ttl)
     return;
@@ -249 +248 @@
 bool PacketCache::getEntry(const string &qname, const QType& qtype, CacheEntryType cet, string& value, int zoneID, bool meritsRecursion)
 {
+  if(d_ttl<0) 
+    getTTLS();
+
+  if(!((d_ops++) % 300000)) {
+    cleanup();
+  }
+
   TryReadLock l(&d_mut); // take a readlock here
   if(!l.gotIt()) {
@@ -254 +260 @@
     return false;
   }
+  return getEntryLocked(qname, qtype, cet, value, zoneID, meritsRecursion);
+}
+
+bool PacketCache::getEntryLocked(const string &qname, const QType& qtype, CacheEntryType cet, string& value, int zoneID, bool meritsRecursion)
+{
 
   uint16_t qt = qtype.getCode();
@@ -261 +272 @@
   if(ret)
     value = i->value;
-  
-  //  cerr<<"Cache hit: "<<(int)cet<<", "<<ret<<endl;
   
   return ret;
@@ -317 +326 @@
 
   unsigned int lookAt=0;
-  // two modes - if toTrim is 0, just look through 10000 records and nuke everything that is expired
+  // two modes - if toTrim is 0, just look through 10%  of the cache and nuke everything that is expired
   // otherwise, scan first 5*toTrim records, and stop once we've nuked enough
   if(toTrim)
@@ -333 +342 @@
   typedef cmap_t::nth_index<1>::type sequence_t;
   sequence_t& sidx=d_map.get<1>();
-  unsigned int erased=0;
-  for(sequence_t::iterator i=sidx.begin(); i != sidx.end();) {
+  unsigned int erased=0, lookedAt=0;
+  for(sequence_t::iterator i=sidx.begin(); i != sidx.end(); lookedAt++) {
     if(i->ttd < now) {
       sidx.erase(i++);
@@ -345 +354 @@
       break;
 
+    if(lookedAt > lookAt)
+      break;
   }
   //  cerr<<"erased: "<<erased<<endl;