Shrink PacketID by 10% by eliminating padding.

PacketID is bloated. Some minor reordering, which shouldn't effect
locality, reduces sizeof(PacketID) from 232 to 208 bytes compiled
against GNU libstdc++ (shipped with GCC 5.3, C++11 ABI) and from 184 to
160 bytes against libc++ 3.7.0. In both cases only 3 bytes of padding
remain for aligning 'bool inIncompleteOkay'.

diff --git a/pdns/syncres.hh b/pdns/syncres.hh
index 9473966a42865963327e2db3b38cf95b5a21a88e..5ed097e9ebfecc92ab0782070797da998d332d59 100644 (file)
--- a/pdns/syncres.hh
+++ b/pdns/syncres.hh
@@ -513,21 +513,21 @@ struct PacketID
   }
 
   uint16_t id;  // wait for a specific id/remote pair
+  uint16_t type;             // and this is its type
   ComboAddress remote;  // this is the remote
   DNSName domain;             // this is the question
-  uint16_t type;             // and this is its type
 
   Socket* sock;  // or wait for an event on a TCP fd
-  int inNeeded; // if this is set, we'll read until inNeeded bytes are read
   string inMSG; // they'll go here
+  int inNeeded; // if this is set, we'll read until inNeeded bytes are read
   bool inIncompleteOkay;
 
   string outMSG; // the outgoing message that needs to be sent
   string::size_type outPos;    // how far we are along in the outMSG
 
-  mutable uint32_t nearMisses; // number of near misses - host correct, id wrong
   typedef set<uint16_t > chain_t;
   mutable chain_t chain;
+  mutable uint32_t nearMisses; // number of near misses - host correct, id wrong
   int fd;
 
   bool operator<(const PacketID& b) const