From ce39630bda121e0a533360da555897b120caf6ca Mon Sep 17 00:00:00 2001
From: Remi Gacogne <remi.gacogne@powerdns.com>
Date: Fri, 11 May 2018 16:20:47 +0200
Subject: [PATCH] calidns: Add an option to stop once we drop below a minimum
 rate

---
 docs/manpages/calidns.1.rst | 22 ++++++++++---------
 pdns/calidns.cc             | 44 ++++++++++++++++++++++++++++++-------
 2 files changed, 48 insertions(+), 18 deletions(-)

diff --git a/docs/manpages/calidns.1.rst b/docs/manpages/calidns.1.rst
index 98ffffe90..96ee6fa39 100644
--- a/docs/manpages/calidns.1.rst
+++ b/docs/manpages/calidns.1.rst
@@ -32,13 +32,15 @@ This is similar to Alexa top 1 million list.
 Options
 -------
 
---ecs <SUBNET>           Add EDNS Client Subnet option to outgoing queries using random
-                         addresses from the specified *SUBNET* range (IPv4 only).
---ecs-from-file          Read IP or subnet values from the query file and add them as EDNS
-                         Client Subnet option to outgoing queries.
---increment <NUM>        On every subsequent run, multiply the number of queries per second
-                         by *NUM*. By default, this is 1.1.
---maximum-qps <NUM>      Stop incrementing once this rate has been reached, to provide a
-                         stable load.
---plot-file <FILE>       Write results to the specified file.
---want-recursion         Set this flag to send queries with the Recursion Desired flag set.
+--ecs <SUBNET>                 Add EDNS Client Subnet option to outgoing queries using random
+                               addresses from the specified *SUBNET* range (IPv4 only).
+--ecs-from-file                Read IP or subnet values from the query file and add them as EDNS
+                               Client Subnet option to outgoing queries.
+--increment <NUM>              On every subsequent run, multiply the number of queries per second
+                               by *NUM*. By default, this is 1.1.
+--maximum-qps <NUM>            Stop incrementing once this rate has been reached, to provide a
+                               stable load.
+--minimum-success-rate <NUM>   Stop the test as soon as the success rate drops below this value,
+                               in percent.
+--plot-file <FILE>             Write results to the specified file.
+--want-recursion               Set this flag to send queries with the Recursion Desired flag set.
diff --git a/pdns/calidns.cc b/pdns/calidns.cc
index 0c1526041..90dbfa90c 100644
--- a/pdns/calidns.cc
+++ b/pdns/calidns.cc
@@ -225,6 +225,7 @@ try
     ("ecs-from-file", "Read IP or subnet values from the query file and add them as EDNS Client Subnet options to outgoing queries")
     ("increment", po::value<float>()->default_value(1.1),  "Set the factor to increase the QPS load per run")
     ("maximum-qps", po::value<uint32_t>(), "Stop incrementing once this rate has been reached, to provide a stable load")
+    ("minimum-success-rate", po::value<double>()->default_value(0), "Stop the test as soon as the success rate drops below this value, in percent")
     ("plot-file", po::value<string>(), "Write results to the specific file")
     ("want-recursion", "Set the Recursion Desired flag on queries");
   po::options_description alloptions;
@@ -283,6 +284,12 @@ try
     maximumQps = g_vm["maximum-qps"].as<uint32_t>();
   }
 
+  double minimumSuccessRate = g_vm["minimum-success-rate"].as<double>();
+  if (minimumSuccessRate > 100.0 || minimumSuccessRate < 0.0) {
+    cerr<<"Minimum success rate must be between 0 and 100, not "<<minimumSuccessRate<<endl;
+    return EXIT_FAILURE;
+  }
+
   Netmask ecsRange;
   if (g_vm.count("ecs")) {
     dns_random_init("0123456789abcdef");
@@ -308,8 +315,9 @@ try
   struct sched_param param;
   param.sched_priority=99;
 
-  if(sched_setscheduler(0, SCHED_FIFO, &param) < 0)
+  if(sched_setscheduler(0, SCHED_FIFO, &param) < 0) {
     cerr<<"Unable to set SCHED_FIFO: "<<strerror(errno)<<endl;
+  }
 
   ifstream ifs(g_vm["query-file"].as<string>());
   string line;
@@ -388,6 +396,9 @@ try
     }
   }
 
+  double bestQPS = 0.0;
+  double bestPerfectQPS = 0.0;
+
   for(qps=qpsstart;;) {
     double seconds=1;
     cout<<"Aiming at "<<qps<< "qps (RD="<<wantRecursion<<") for "<<seconds<<" seconds at cache hitrate "<<100.0*hitrate<<"%";
@@ -400,7 +411,7 @@ try
 
     if (misses > unknown.size()) {
       cerr<<"Not enough queries remaining (need at least "<<misses<<" and got "<<unknown.size()<<", please add more to the query file), exiting."<<endl;
-      exit(1);
+      return EXIT_FAILURE;
     }
     vector<vector<uint8_t>*> toSend;
     unsigned int n;
@@ -421,22 +432,39 @@ try
 
     sendPackets(&sockets, toSend, qps, dest, ecsRange);
     
-    auto udiff = dt.udiff();
-    auto realqps=toSend.size()/(udiff/1000000.0);
-    cout<<"Achieved "<<realqps<<"qps"<< " over "<< udiff/1000000.0<<" seconds"<<endl;
+    const auto udiff = dt.udiffNoReset();
+    const auto realqps=toSend.size()/(udiff/1000000.0);
+    cout<<"Achieved "<<realqps<<" qps over "<< udiff/1000000.0<<" seconds"<<endl;
     
     usleep(50000);
-    double perc=g_recvcounter.load()*100.0/toSend.size();
-    cout<<"Received "<<g_recvcounter.load()<<" packets ("<<perc<<"%)"<<endl;
+    const auto received = g_recvcounter.load();
+    const auto udiffReceived = dt.udiff();
+    const auto realReceivedQPS = received/(udiffReceived/1000000.0);
+    double perc=received*100.0/toSend.size();
+    cout<<"Received "<<received<<" packets over "<< udiffReceived/1000000.0<<" seconds ("<<perc<<"%, adjusted received rate "<<realReceivedQPS<<" qps)"<<endl;
 
     if (plot) {
-      plot<<qps<<" "<<realqps<<" "<<perc<<" "<<g_recvcounter.load()/(udiff/1000000.0)<<" " << 8*g_recvbytes.load()/(udiff/1000000.0)<<endl;
+      plot<<qps<<" "<<realqps<<" "<<perc<<" "<<received/(udiff/1000000.0)<<" " << 8*g_recvbytes.load()/(udiff/1000000.0)<<endl;
       plot.flush();
     }
 
     if (qps < maximumQps) {
       qps *= increment;
     }
+    else {
+      qps = maximumQps;
+    }
+
+    if (minimumSuccessRate > 0.0 && perc < minimumSuccessRate) {
+      cout<<"The latest success rate ("<<perc<<") dropped below the minimum success rate of "<<minimumSuccessRate<<", stopping."<<endl;
+      cout<<"The final rate reached before failing was "<<bestQPS<<" qps (best rate at 100% was "<<bestPerfectQPS<<" qps)"<<endl;
+      break;
+    }
+
+    bestQPS = std::max(bestQPS, realReceivedQPS);
+    if (perc >= 100.0) {
+      bestPerfectQPS = std::max(bestPerfectQPS, realReceivedQPS);
+    }
   }
 
   if (plot) {
-- 
2.40.0