1 files changed, 5 insertions, 1 deletions

diff --git a/type/GenericIO.class.php b/type/GenericIO.class.php
index a0a9666..3a29948 100644
--- a/type/GenericIO.class.php
+++ b/type/GenericIO.class.php
@@ -35,6 +35,8 @@ class Type_GenericIO extends Type_Base {
                                         $rrdgraph[] = sprintf('VDEF:tot_%1$s=avg_%1$s,TOTAL', crc32hex($sources[$i]));
                                         if ($this->percentile)
                                                 $rrdgraph[] = sprintf('VDEF:pct_%1$s=avg_%1$s,%2$s,PERCENT', crc32hex($sources[$i]), $this->percentile);
+                                        if ($this->percentile && $this->negative_io && $i == 1)
+                                                $rrdgraph[] = sprintf('VDEF:pct_%1$s_neg=avg_%1$s_neg,%2$s,PERCENT', crc32hex($sources[$i]), 100 - $this->percentile);
                                         $i++;
                                 }
                         }
@@ -70,10 +72,12 @@ class Type_GenericIO extends Type_Base {
 
                 if ($this->percentile) {
                         $rrdgraph[] = 'COMMENT: \l';
+                        $i=0;
                         foreach($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));
+                                $rrdgraph[] = sprintf('LINE:pct_%s%s#%s:%sth Percentile %s', crc32hex($source), ($i == 1 && $this->negative_io) ? '_neg' : '', $this->get_faded_color($this->colors[$source], '000000', 0.6), $this->percentile, $this->rrd_escape($legend));
                                 $rrdgraph[] = sprintf('GPRINT:pct_%s:%s\l', crc32hex($source), $this->rrd_format);
+                                $i++;
                         }
                 }