Hello,
we are using G1GC and noticing garbage collection taking a while and during
that process we are seeing cpu spiking up to 70-80%. can you please let us
know. if we have to tune any parameters for that. attaching the cassandra-env
file with jam-options.
calculate_heap_sizes()
{
case "`uname`" in
Linux)
system_memory_in_mb=`free -m | awk '/:/ {print $2;exit}'`
system_cpu_cores=`egrep -c 'processor([[:space:]]+):.*'
/proc/cpuinfo`
;;
FreeBSD)
system_memory_in_bytes=`sysctl hw.physmem | awk '{print $2}'`
system_memory_in_mb=`expr $system_memory_in_bytes / 1024 / 1024`
system_cpu_cores=`sysctl hw.ncpu | awk '{print $2}'`
;;
SunOS)
system_memory_in_mb=`prtconf | awk '/Memory size:/ {print $3}'`
system_cpu_cores=`psrinfo | wc -l`
;;
Darwin)
system_memory_in_bytes=`sysctl hw.memsize | awk '{print $2}'`
system_memory_in_mb=`expr $system_memory_in_bytes / 1024 / 1024`
system_cpu_cores=`sysctl hw.ncpu | awk '{print $2}'`
;;
*)
system_memory_in_mb="2048"
system_cpu_cores="2"
;;
esac
if [ "$system_cpu_cores" -lt "1" ]
then
system_cpu_cores="1"
fi
half_system_memory_in_mb=`expr $system_memory_in_mb / 2`
quarter_system_memory_in_mb=`expr $half_system_memory_in_mb / 2`
if [ "$half_system_memory_in_mb" -gt "1024" ]
then
half_system_memory_in_mb="1024"
fi
if [ "$quarter_system_memory_in_mb" -gt "8192" ]
then
quarter_system_memory_in_mb="8192"
fi
if [ "$half_system_memory_in_mb" -gt "$quarter_system_memory_in_mb" ]
then
max_heap_size_in_mb="$half_system_memory_in_mb"
else
max_heap_size_in_mb="$quarter_system_memory_in_mb"
fi
MAX_HEAP_SIZE="${max_heap_size_in_mb}M"
max_sensible_yg_per_core_in_mb="100"
max_sensible_yg_in_mb=`expr $max_sensible_yg_per_core_in_mb "*"
$system_cpu_cores`
desired_yg_in_mb=`expr $max_heap_size_in_mb / 4`
if [ "$desired_yg_in_mb" -gt "$max_sensible_yg_in_mb" ]
then
HEAP_NEWSIZE="${max_sensible_yg_in_mb}M"
else
HEAP_NEWSIZE="${desired_yg_in_mb}M"
fi
}
java_ver_output=`"${JAVA:-java}" -version 2>&1`
jvmver=`echo "$java_ver_output" | grep '[openjdk|java] version' | awk -F'"'
'NR==1 {print $2}' | cut -d\- -f1`
JVM_VERSION=${jvmver%_*}
if [ "$JVM_VERSION" \< "1.8" ] ; then
echo "Cassandra 3.0 and later require Java 8u40 or later."
exit 1;
fi
if [ "$JVM_VERSION" \< "1.8" ] && [ "$JVM_PATCH_VERSION" -lt 40 ] ; then
echo "Cassandra 3.0 and later require Java 8u40 or later."
exit 1;
fi
jvm=`echo "$java_ver_output" | grep -A 1 'java version' | awk 'NR==2 {print
$1}'`
case "$jvm" in
OpenJDK)
JVM_VENDOR=OpenJDK
JVM_ARCH=`echo "$java_ver_output" | awk 'NR==3 {print $2}'`
;;
"Java(TM)")
JVM_VENDOR=Oracle
JVM_ARCH=`echo "$java_ver_output" | awk 'NR==3 {print $3}'`
;;
*)
JVM_VENDOR=other
JVM_ARCH=unknown
;;
esac
JVM_OPTS="$JVM_OPTS -Xloggc:$CASSANDRA_LOG/gc.log"
JVM_OPTS_FILE=$CASSANDRA_CONF/jvm.options
for opt in `grep "^-" $JVM_OPTS_FILE`
do
JVM_OPTS="$JVM_OPTS $opt"
done
echo $JVM_OPTS | grep -q Xmn
DEFINED_XMN=$?
echo $JVM_OPTS | grep -q Xmx
DEFINED_XMX=$?
echo $JVM_OPTS | grep -q Xms
DEFINED_XMS=$?
echo $JVM_OPTS | grep -q UseConcMarkSweepGC
USING_CMS=$?
echo $JVM_OPTS | grep -q UseG1GC
USING_G1=$?
MAX_HEAP_SIZE="8192M"
HEAP_NEWSIZE="800M"
if [ "x$MAX_HEAP_SIZE" = "x" ] && [ "x$HEAP_NEWSIZE" = "x" -o $USING_G1 -eq 0
]; then
calculate_heap_sizes
elif [ "x$MAX_HEAP_SIZE" = "x" ] || [ "x$HEAP_NEWSIZE" = "x" -a $USING_G1 -ne
0 ]; then
echo "please set or unset MAX_HEAP_SIZE and HEAP_NEWSIZE in pairs when
using CMS GC (see cassandra-env.sh)"
exit 1
fi
if [ "x$MALLOC_ARENA_MAX" = "x" ] ; then
export MALLOC_ARENA_MAX=4
fi
if [ $DEFINED_XMX -ne 0 ] && [ $DEFINED_XMS -ne 0 ]; then
JVM_OPTS="$JVM_OPTS -Xms${MAX_HEAP_SIZE}"
JVM_OPTS="$JVM_OPTS -Xmx${MAX_HEAP_SIZE}"
elif [ $DEFINED_XMX -ne 0 ] || [ $DEFINED_XMS -ne 0 ]; then
echo "Please set or unset -Xmx and -Xms flags in pairs on jvm.options
file."
exit 1
fi
if [ $DEFINED_XMN -eq 0 ] && [ $DEFINED_XMX -ne 0 ]; then
echo "Please set or unset -Xmx and -Xmn flags in pairs on jvm.options file."
exit 1
elif [ $DEFINED_XMN -ne 0 ] && [ $USING_CMS -eq 0 ]; then
JVM_OPTS="$JVM_OPTS -Xmn${HEAP_NEWSIZE}"
fi
if [ "$JVM_ARCH" = "64-Bit" ] && [ $USING_CMS -eq 0 ]; then
JVM_OPTS="$JVM_OPTS -XX:+UseCondCardMark"
fi
JVM_OPTS="$JVM_OPTS -XX:CompileCommandFile=$CASSANDRA_CONF/hotspot_compiler"
JVM_OPTS="$JVM_OPTS -javaagent:$CASSANDRA_HOME/lib/jamm-0.3.0.jar"
if [ "x$CASSANDRA_HEAPDUMP_DIR" != "x" ]; then
JVM_OPTS="$JVM_OPTS
-XX:HeapDumpPath=$CASSANDRA_HEAPDUMP_DIR/cassandra-`date +%s`-pid$$.hprof"
fi
if [ "x$LOCAL_JMX" = "x" ]; then
LOCAL_JMX=yes
fi
JMX_PORT="7199"
if [ "$LOCAL_JMX" = "yes" ]; then
JVM_OPTS="$JVM_OPTS -Dcassandra.jmx.local.port=$JMX_PORT"
JVM_OPTS="$JVM_OPTS -Dcom.sun.management.jmxremote.authenticate=false"
else
JVM_OPTS="$JVM_OPTS -Dcassandra.jmx.remote.port=$JMX_PORT"
JVM_OPTS="$JVM_OPTS -Dcom.sun.management.jmxremote.rmi.port=$JMX_PORT"
JVM_OPTS="$JVM_OPTS -Dcom.sun.management.jmxremote.authenticate=true"
fi
JVM_OPTS="$JVM_OPTS
-Dcom.sun.management.jmxremote.password.file=/etc/cassandra/jmxremote.password"
JVM_OPTS="$JVM_OPTS -Djava.library.path=$CASSANDRA_HOME/lib/sigar-bin"
JVM_OPTS="$JVM_OPTS $MX4J_ADDRESS"
JVM_OPTS="$JVM_OPTS $MX4J_PORT"
JVM_OPTS="$JVM_OPTS $JVM_EXTRA_OPTS"
and jvm-options file
-ea
-XX:+UseThreadPriorities
-XX:ThreadPriorityPolicy=42
-XX:+HeapDumpOnOutOfMemoryError
-Xss256k
-XX:StringTableSize=1000003
-XX:+AlwaysPreTouch
-XX:-UseBiasedLocking
-XX:+UseTLAB
-XX:+ResizeTLAB
-XX:+UseNUMA
-XX:+PerfDisableSharedMem
-Djava.net.preferIPv4Stack=true
-XX:+UseG1GC
-XX:G1RSetUpdatingPauseTimePercent=5
-XX:MaxGCPauseMillis=500
-XX:+PrintGCDetails
-XX:+PrintGCDateStamps
-XX:+PrintHeapAtGC
-XX:+PrintTenuringDistribution
-XX:+PrintGCApplicationStoppedTime
-XX:+PrintPromotionFailure
-XX:+UseGCLogFileRotation
-XX:NumberOfGCLogFiles=10
-XX:GCLogFileSize=10M
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