rec: Add a distribution-pipe-buffer-size setting

[thirdparty/pdns.git] / pdns / pdns_recursor.cc

diff --git a/pdns/pdns_recursor.cc b/pdns/pdns_recursor.cc
index d0b8b121c28f3c73a155e3cb430d7e43589893d0..1e171080c00231e789afb398fb6302df39b12c0c 100644 (file)
--- a/pdns/pdns_recursor.cc
+++ b/pdns/pdns_recursor.cc
@@ -2781,6 +2781,11 @@ static void houseKeeping(void *)
 
 static void makeThreadPipes()
 {
+  auto pipeBufferSize = ::arg().asNum("distribution-pipe-buffer-size");
+  if (pipeBufferSize > 0) {
+    g_log<<Logger::Info<<"Resizing the buffer of the distribution pipe to "<<pipeBufferSize<<endl;
+  }
+
   /* thread 0 is the handler / SNMP, we start at 1 */
   for(unsigned int n = 1; n <= (g_numWorkerThreads + g_numDistributorThreads); ++n) {
     auto& threadInfos = s_threadInfos.at(n);
@@ -2804,6 +2809,16 @@ static void makeThreadPipes()
     threadInfos.pipes.readQueriesToThread = fd[0];
     threadInfos.pipes.writeQueriesToThread = fd[1];
 
+    if (pipeBufferSize > 0) {
+      if (!setPipeBufferSize(threadInfos.pipes.writeQueriesToThread, pipeBufferSize)) {
+        g_log<<Logger::Warning<<"Error resizing the buffer of the distribution pipe for thread "<<n<<" to "<<pipeBufferSize<<": "<<strerror(errno)<<endl;
+        auto existingSize = getPipeBufferSize(threadInfos.pipes.writeQueriesToThread);
+        if (existingSize > 0) {
+          g_log<<Logger::Warning<<"The current size of the distribution pipe's buffer for thread "<<n<<" is "<<existingSize<<endl;
+        }
+      }
+    }
+
     if (!setNonBlocking(threadInfos.pipes.writeQueriesToThread)) {
       unixDie("Making pipe for inter-thread communications non-blocking");
     }
@@ -4402,6 +4417,7 @@ int main(int argc, char **argv)
     ::arg().set("max-recursion-depth", "Maximum number of internal recursion calls per query, 0 for unlimited")="40";
     ::arg().set("max-udp-queries-per-round", "Maximum number of UDP queries processed per recvmsg() round, before returning back to normal processing")="10000";
     ::arg().set("protobuf-use-kernel-timestamp", "Compute the latency of queries in protobuf messages by using the timestamp set by the kernel when the query was received (when available)")="";
+    ::arg().set("distribution-pipe-buffer-size", "Size in bytes of the internal buffer of the pipe used by the distributor to pass incoming queries to a worker thread")="0";
 
     ::arg().set("include-dir","Include *.conf files from this directory")="";
     ::arg().set("security-poll-suffix","Domain name from which to query security update notifications")="secpoll.powerdns.com.";