# First column is a timestamp, second column is a response time.  Example:
# "time","response"
# 2009-11-23 07:34:01.778955,0.599255
data <- read.csv("~/response_log.csv", header=TRUE)
processed_time <- transform(data$time, strptime(data$time, "%Y-%m-%d %H:%M:%S"))
plot(processed_time, data$response)