Basho Bench summary png, what is the meaning of Latency Percentile

Kevin Burton rkevinburton at
Thu Apr 11 12:37:19 EDT 2013

This a tangential question but I cannot get the PNG device to work. I get
the error:


priv/summary.r -i tests/current

[1] "plyr"

Loading required package: plyr

[1] "grid"

Loading required package: grid

[1] "getopt"

Loading required package: getopt

[1] "proto"

Loading required package: proto

[1] "ggplot2"

Loading required package: ggplot2

Loading required package: methods

[1] 0

[1] 301.168

Error in X11(paste("png::", filename, sep = ""), g$width, g$height,
pointsize,  : 

  unable to start device PNG

Calls: png

In addition: Warning message:

In png(file = opt$outfile, width = opt$width, height = opt$height) :

  unable to open connection to X11 display ''

Execution halted

make: *** [results] Error 1




From: riak-users [mailto:riak-users-bounces at] On Behalf Of
Christian Steinmann
Sent: Thursday, April 11, 2013 5:42 AM
To: riak-users at
Subject: Basho Bench summary png, what is the meaning of Latency Percentile




at the moment i evaluate a graphics (summary.png) generated with Basho Bench
and R.

I wonder what the meaning of this 99th, 99.9th and 95th Percentile curves


My guess is that for e.g. 99th curve means: 99% of all measured latencies
(one measured value for each node at a definite time) have been lower than
the shown value at one point in time.


I only have three nodes in this cluster, so i guess the 99.9th, 99th and
95th curves are showing the latency for one of the nodes in this particular



Can someone explain it to me please.


I added one summary picture.


greetings christian




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