Improve packet cache sizing.

Since queries incoming over TCP are now also using the packet
cache, there is now also one packet cache instance per distributor
thread. Each cache instance has a size of max-packetcache-entries
divided by (threads + distributor-threads).

diff --git a/pdns/pdns_recursor.cc b/pdns/pdns_recursor.cc
index 72588567aca192ab90999c247147b006bf188454..0015f747f3b6fed201d6662278270e162b75ae64 100644 (file)
--- a/pdns/pdns_recursor.cc
+++ b/pdns/pdns_recursor.cc
@@ -3577,7 +3577,7 @@ static void houseKeeping(void *)
     past = now;
     past.tv_sec -= 5;
     if (last_prune < past) {
-      t_packetCache->doPruneTo(g_maxPacketCacheEntries / g_numWorkerThreads);
+      t_packetCache->doPruneTo(g_maxPacketCacheEntries / (g_numWorkerThreads + g_numDistributorThreads));
 
       time_t limit;
       if(!((cleanCounter++)%40)) {  // this is a full scan!

diff --git a/pdns/recursordist/docs/settings.rst b/pdns/recursordist/docs/settings.rst
index e5c01550d4ed9b87e23e1e77b755a1071a5bdb07..b90ed721524693b9405d68cfd15233470885f4d1 100644 (file)
--- a/pdns/recursordist/docs/settings.rst
+++ b/pdns/recursordist/docs/settings.rst
@@ -1038,8 +1038,8 @@ Maximum number of simultaneous MTasker threads.
 -  Integer
 -  Default: 500000
 
-Maximum number of Packet Cache entries.
-This number will be divided by the number of worker threads to compute the number of entries per thread.
+Maximum number of Packet Cache entries. Each worker and each distributor thread has a packets cache instance.
+This number will be divided by the number of worker plus the number of distributor threads to compute the maximum number of entries per cache instance.
 
 .. _setting-max-qperq:
 

diff --git a/pdns/recursordist/docs/upgrade.rst b/pdns/recursordist/docs/upgrade.rst
index 0548d67d335f0c2a69dd8e0df3503b827bc35553..3bf167dc7e2c185f11df22ca8018e1ec47702f9c 100644 (file)
--- a/pdns/recursordist/docs/upgrade.rst
+++ b/pdns/recursordist/docs/upgrade.rst
@@ -53,6 +53,9 @@ Deprecated and changed settings
 - The :ref:`setting-minimum-ttl-override` and :ref:`setting-ecs-minimum-ttl-override` defaults have ben changed from 0 to 1.
 - The :ref:`setting-spoof-nearmiss-max` default has been changed from 20 to 1.
 - The :ref:`setting-dnssec` default has changed from ``process-no-validate`` to ``process``.
+- The meaning of the :ref:`setting-max-packetcache-entries` has changed: previously there was one packet cache instance per worker thread.
+  Since queries incoming over TCP are now also using the packet cache, there is now also one packet cache instance per distributor thread.
+  Each cache instance has a size of :ref:`setting-max-packetcache-entries` divided by (:ref:`setting-threads` + :ref:`setting-distributor-threads`).
 
 Removed settings
 ^^^^^^^^^^^^^^^^