4 files changed, 19 insertions, 0 deletions

diff --git a/conf/config.php b/conf/config.php
index b086455..3d54e26 100644
--- a/conf/config.php
+++ b/conf/config.php
@@ -55,6 +55,10 @@ $CONFIG['rrd_fetch_method'] = 'sync';
 # use the negative X-axis in I/O graphs
 $CONFIG['negative_io'] = false;
 
+# add XXth percentile line + legend to network graphs
+# false = disabled; 95 = 95th percentile
+$CONFIG['percentile'] = false;
+
 # create smooth graphs (rrdtool -E)
 $CONFIG['graph_smooth'] = false;
 
diff --git a/graph.php b/graph.php
index 55be9e9..dadb2c5 100644
--- a/graph.php
+++ b/graph.php
@@ -92,6 +92,9 @@ if (isset($plugin_json[$type]['rrdtool_opts'])) {
 if (isset($plugin_json[$type]['datasize']) and $plugin_json[$type]['datasize'])
         $obj->scale = $CONFIG['network_datasize'] == 'bits' ? 8 : 1;
 
+if ($type == 'if_octets')
+        $obj->percentile = $CONFIG['percentile'];
+
 if (isset($plugin_json[$type]['scale']))
         $obj->scale = $plugin_json[$type]['scale'];
 
diff --git a/type/Base.class.php b/type/Base.class.php
index 40f3df0..883c98f 100644
--- a/type/Base.class.php
+++ b/type/Base.class.php
@@ -22,6 +22,7 @@ class Type_Base {
         var $height;
         var $graph_type;
         var $negative_io;
+        var $percentile = false;
         var $graph_smooth;
 
         var $files;
diff --git a/type/GenericIO.class.php b/type/GenericIO.class.php
index fac7034..a9d58cd 100644
--- a/type/GenericIO.class.php
+++ b/type/GenericIO.class.php
@@ -33,6 +33,8 @@ class Type_GenericIO extends Type_Base {
                                         if ($i == 1)
                                                 $rrdgraph[] = sprintf('CDEF:avg_%s_neg=avg_%1$s_raw,%s%s,*', crc32hex($sources[$i]), $this->negative_io ? '-' : '', $this->scale);
                                         $rrdgraph[] = sprintf('VDEF:tot_%1$s=avg_%1$s,TOTAL', crc32hex($sources[$i]));
+                                        if ($this->percentile)
+                                                $rrdgraph[] = sprintf('VDEF:pct_%1$s=avg_%1$s_raw,%2$s,PERCENT', crc32hex($sources[$i]), $this->percentile);
                                         $i++;
                                 }
                         }
@@ -66,6 +68,15 @@ class Type_GenericIO extends Type_Base {
                         $i++;
                 }
                 
+                if ($this->percentile) {
+                        $rrdgraph[] = sprintf('"COMMENT: \l"');
+                        foreach($sources as $source) {
+                                $legend = empty($this->legend[$source]) ? $source : $this->legend[$source];
+                                $rrdgraph[] = sprintf('"HRULE:pct_%s#%s:%sth Percentile %s"', crc32hex($source), $this->get_faded_color($this->colors[$source], '000000', 0.6), $this->percentile, $this->rrd_escape($legend));
+                                $rrdgraph[] = sprintf('"GPRINT:pct_%s:%s\l"', crc32hex($source), $this->rrd_format);
+                        }
+                }
+
                 return $rrdgraph;
         }
 }