Merge "Enable CSV logging output for DStat."

lib/dstat

@@ -19,8 +19,7 @@ set +o xtrace
 # start_dstat() - Start running processes, including screen
 function start_dstat {
     # A better kind of sysstat, with the top process per time slice
-    DSTAT_OPTS="-tcmndrylpg --top-cpu-adv --top-io-adv"
-    run_process dstat "dstat $DSTAT_OPTS"
+    run_process dstat "$TOP_DIR/tools/dstat.sh $LOGDIR"
 
     # To enable peakmem_tracker add:
     #    enable_service peakmem_tracker

tools/dstat.sh

@@ -0,0 +1,32 @@
+#!/bin/bash
+
+# **tools/dstat.sh** - Execute instances of DStat to log system load info
+#
+# Multiple instances of DStat are executed in order to take advantage of
+# incompatible features, particularly CSV output and the "top-cpu-adv" and
+# "top-io-adv" flags.
+#
+# Assumes:
+#  - dstat command is installed
+
+# Retreive log directory as argument from calling script.
+LOGDIR=$1
+
+# Command line arguments for primary DStat process.
+DSTAT_OPTS="-tcmndrylpg --top-cpu-adv --top-io-adv"
+
+# Command-line arguments for secondary background DStat process.
+DSTAT_CSV_OPTS="-tcmndrylpg --output $LOGDIR/dstat-csv.log"
+
+# Execute and background the secondary dstat process and discard its output.
+dstat $DSTAT_CSV_OPTS >& /dev/null &
+
+# Execute and background the primary dstat process, but keep its output in this
+# TTY.
+dstat $DSTAT_OPTS &
+
+# Catch any exit signals, making sure to also terminate any child processes.
+trap "kill -- -$$" EXIT
+
+# Keep this script running as long as child dstat processes are alive.
+wait