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# jmaps - creates java /tmp/perf-PID.map symbol maps for all java processes.
#
# This is a helper script that finds all running "java" processes, then executes
# perf-map-agent on them all, creating symbol map files in /tmp. These map files
# are read by perf_events (aka "perf") when doing system profiles (specifically,
# the "report" and "script" subcommands).
#
# My typical workflow is this:
#
# perf record -F 99 -a -g -- sleep 30; jmaps
# perf script > out.stacks
# ./stackcollapse-perf.pl out.stacks | ./flamegraph.pl --color=java --hash > out.stacks.svg
#
# The stackcollapse-perf.pl and flamegraph.pl programs come from:
# https://github.com/brendangregg/FlameGraph
#
# REQUIREMENTS:
# Tune two environment settings below.
#
# 13-Feb-2015 Brendan Gregg Created this.
JAVA_HOME=/usr/lib/jvm/java-8-oracle
AGENT_HOME=/usr/lib/jvm/perf-map-agent # from https://github.com/jrudolph/perf-map-agent
if [[ "$USER" != root ]]; then
echo "ERROR: not root user? exiting..."
exit
fi
if [[ ! -x $JAVA_HOME ]]; then
echo "ERROR: JAVA_HOME not set correctly; edit $0 and fix"
exit
fi
if [[ ! -x $AGENT_HOME ]]; then
echo "ERROR: AGENT_HOME not set correctly; edit $0 and fix"
exit
fi
# figure out where the agent files are:
AGENT_OUT=""
AGENT_JAR=""
if [[ -e $AGENT_HOME/out/attach-main.jar ]]; then
AGENT_JAR=$AGENT_HOME/out/attach-main.jar
elif [[ -e $AGENT_HOME/attach-main.jar ]]; then
AGENT_JAR=$AGENT_HOME/attach-main.jar
fi
if [[ -e $AGENT_HOME/out/libperfmap.so ]]; then
AGENT_OUT=$AGENT_HOME/out
elif [[ -e $AGENT_HOME/libperfmap.so ]]; then
AGENT_OUT=$AGENT_HOME
fi
if [[ "$AGENT_OUT" == "" || "$AGENT_JAR" == "" ]]; then
echo "ERROR: Missing perf-map-agent files in $AGENT_HOME. Check installation."
exit
fi
echo "Fetching maps for all java processes..."
for pid in $(pgrep -x java); do
mapfile=/tmp/perf-$pid.map
[[ -e $mapfile ]] && rm $mapfile
cmd="cd $AGENT_OUT; $JAVA_HOME/bin/java -Xms32m -Xmx128m -cp $AGENT_JAR:$JAVA_HOME/lib/tools.jar net.virtualvoid.perf.AttachOnce $pid"
echo $cmd
user=$(ps ho user -p $pid)
if [[ "$user" != root ]]; then
# make $user the username if it is a UID:
if [[ "$user" == [0-9]* ]]; then user=$(awk -F: '$3 == '$user' { print $1 }' /etc/passwd); fi
cmd="sudo -u $user sh -c '$cmd'"
fi
echo "Mapping PID $pid (user $user):"
time eval $cmd
if [[ -e "$mapfile" ]]; then
chown root $mapfile
chmod 666 $mapfile
else
echo "ERROR: $mapfile not created."
fi
echo
echo "wc(1): $(wc $mapfile)"
echo
done