Useful scripts to collect/display perf results.

Add shell scripts to make it easier to collect performance results from
traces, live tests, and phoronix tests.

With run_performance_tests.sh you specify the following:
  - a subject program to run, using --root
  - a name to give to this set of results, using --variant
  - a test to run, using --test
  - a file to write the results to, using --results.

For tests that start with "trace", the script runs falco/sysdig on the
trace file and measures the time taken to read the file. For other
tests, he script handles starting falco/sysdig, starting a cpu
measurement script (a wrapper around top, just to provide identical
values to what you would see using top) to measure the cpu usage of
falco/sysdig, and running a live test.

The measurement interval for cpu usage depends on the test being run--10
seconds for most tests, 2 seconds for shorter tests.

The output is written as json to the file specified in --results.

Also add R scripts to easily display the results from the shell
script. plot-live.r shows a linechart of the cpu usage for the provided
variants over time. plot-traces.r shows grouped barcharts showing
user/system/total time taken for the provided variants and traces.

One bug--you have to make the results file actual json by adding
leading/trailing []s.

test/plot-traces.r

@@ -0,0 +1,35 @@
+require(jsonlite)
+library(ggplot2)
+library(reshape)
+
+res <- fromJSON("/home/mstemm/results.txt", flatten=TRUE)
+
+plot <- ggplot(data=res, aes(x=config, y=elapsed.real)) +
+    geom_bar(stat = "summary", fun.y = "mean") +
+    coord_flip() +
+    facet_grid(shortfile ~ .) +
+    ylab("Wall Clock Time (sec)") +
+    xlab("Trace File/Program")
+
+
+ggsave(file="/mnt/sf_mstemm/res-real.png")
+
+plot <- ggplot(data=res, aes(x=config, y=elapsed.user)) +
+    geom_bar(stat = "summary", fun.y = "mean") +
+    coord_flip() +
+    facet_grid(shortfile ~ .) +
+    ylab("User Time (sec)") +
+    xlab("Trace File/Program")
+
+
+ggsave(file="/mnt/sf_mstemm/res-user.png")
+
+res2 <- melt(res, id.vars = c("config", "shortfile"), measure.vars = c("elapsed.sys", "elapsed.user"))
+plot <- ggplot(data=res2, aes(x=config, y=value, fill=variable, order=variable)) +
+     geom_bar(stat = "summary", fun.y = "mean") +
+     coord_flip() +
+     facet_grid(shortfile ~ .) +
+     ylab("User/System Time (sec)") +
+     xlab("Trace File/Program")
+
+ggsave(file="/mnt/sf_mstemm/res-sys-user.png")