In older versions of psutils, the application ps does not have etimes. This is a quick documentation on how to gather etimes from the procfs.

What is etimes?

Man:

       etimes      ELAPSED   elapsed time since the process was started, in seconds.

Example:

$ ps -Lo pid,etimes,comm --pid 4398 --sort +etimes
  PID ELAPSED COMMAND
 4398     359 java
 4398     358 java
 4398     358 java
 4398     354 java
 4398     351 java
 4398     351 java
 4398     349 gmain
 4398     349 gdbus
 4398     348 java
 4398     329 java
 4398      52 java
...

The etimes is the number of seconds that have passed since a process was created. Checking the source code of psutils we can see;

etimes = seconds_since_boot - (unsigned long)(pp->start_time / Hertz);

1. seconds_since_boot we can get from /proc/stat
2. start_time we can get from /proc//task//stat
3. Hertz we can get with a c program or the utility getconf

Seconds Since Boot

we can calculate the seconds since boot by subtracting the boot time from the current time. In the file /proc/stat we can find the following;

              btime 769041601
                     boot time, in seconds since the Epoch, 1970-01-01 00:00:00 +0000 (UTC).

with:

$ cat /proc/stat | grep btime | awk '{print $2}'
1485890751

and we can get the current time since epoch using:

$ date +%s
1485893129

so we know this system has been up for a total of 2378 seconds.

Process Start Time

The process start time can be taken from /proc//task//stat;

              (22) starttime  %llu
                        The  time  the  process started after system boot.  In kernels before Linux 2.6, this value was expressed in jiffies.  Since Linux 2.6, the value is expressed in
                        clock ticks (divide by sysconf(_SC_CLK_TCK)).

with this we can get the value:

$ cat /proc/$JAVA_PID/task/$LWP/stat | awk '{print $22}'
140205

Hertz

For the purpose of this bash script we can get the hertz of the system using:

$ getconf CLK_TCK
100

Calculating

With all the numbers gatherd we can now calculate:

$ bc <<< "scale=2; 2378 - (140205/100)"
975.95

Comparing and Validating

$ bc <<< "scale=2; $(($(date +"%s")-$(cat /proc/stat | grep btime | awk '{print $2}'))) - ($(cat /proc/4398/task/4616/stat | awk '{print $22}')/$(getconf CLK_TCK))"; ps -Lo lwp,etime,etimes --pid 4398 | grep 4616
4250.95
 4616    01:10:51    4251

We can see the value we've pulled from procfs matches the value provided from psutil.

Why do all of this rather that formating etime?

Getting to know my system better... it also opens the door to a vast array of other stats that can be pulled for monitoring purposes including per thread netstat.

Full Bash Script For Java Thread Dumps:

kept up to date in github: https://github.com/mikejonesey/take-jstacks/blob/master/take-stacks.sh

#!/bin/bash
################################################
# take-stacks.sh
# take stack traces with the pcpu mapped to each thread
# this can be used to identify which threads are consuming cpu
# Additional Info added to JAVA Thread Dumps:
#   - pcpu (percentage of cpu usage on the current core)
#   - cpu core
#   - page faults major + minor
#   - etimes (how long the process has been running)
# Author        Michael Jones
# Date          07/08/2015
################################################
#

TRACE_COUNT=1
TRACE_INTERVAL=1
JAVA_PID=$(ps -ef | grep java | grep -v grep | tail -1 | awk '{print $2}')
TMP_DIR="/tmp/$(date +"%Y-%m-%d")"

mkdir $TMP_DIR 2>/dev/null

ps -o etimes &>/dev/null
if [ "$?" == "0" ]; then
    etimes_valid=true
else
    etimes_valid=false
fi

for ((i=0; i<$TRACE_COUNT; i++)); do
    TRACETIME=$(date +"%s")
    if [ $etimes_valid == true ]; then
        EXINF=$(ps -eLo pcpu,lwp,sgi_p,maj_flt,min_flt,etimes,cmd | grep java | grep -v grep | sort -k1,1 -n | while read al; do nid=$(printf "0x%xn" $(echo "$al" | awk '{print $2}')); echo "$nid $al"; done)
    else
        SYS_BOOTTIME=$(cat /proc/stat | grep btime | awk '{print $2}') # boot time, in seconds since the Epoch (January 1, 1970)
        SYS_JIFFPS=$(getconf CLK_TCK) # jiffies ps
        SYS_CURTIME=$(date +"%s") # time since epo
        SYS_UPTIME=$(($SYS_CURTIME-$SYS_BOOTTIME)) # uptime in secs
        EXINF=$(ps -eLo pcpu,lwp,sgi_p,maj_flt,min_flt,cmd | grep java | grep -v grep | sort -k1,1 -n | while read al; do
            LWP=$(echo "$al" | awk '{print $2}')
            if [ -f "/proc/$JAVA_PID/task/$LWP/stat" ]; then
                nid=$(printf "0x%xn" $LWP)
                THREAD_STIME=$(cat /proc/$JAVA_PID/task/$LWP/stat | awk '{print $22}')
                THREAD_ETIME=$(bc <<< "scale=2; $SYS_UPTIME - ($THREAD_STIME/$SYS_JIFFPS)")
                TIMESTAMP=$(date -d@$(($SYS_CURTIME-$(echo "$THREAD_ETIME" | sed 's/..*//'))) +"%Y-%m-%d_%H:%M:%S")
                etimes="$THREAD_STIME $THREAD_ETIME $TIMESTAMP"
            else
                etimes="-1 -1 -1"
            fi
            echo "$nid $etimes $al"
        done)
    fi
    jstack -l "$JAVA_PID" > $TMP_DIR/stack-$TRACETIME.out
    echo "$EXINF" | while read al; do
        NID=$(echo "$al" | awk '{print $1}')
        if [ $etimes_valid == true ]; then
            ESTR="$(echo "$al" | awk '{print "pcpu=" $2 " core=" $4 " page=" $5 " mpage=" $6 " secs=" $7}')"
        else
            ESTR="$(echo "$al" | awk '{print "pcpu=" $5 " core=" $7 " page=" $8 " mpage=" $9 " jifftime=" $2 " secs=" $3 " time=" $4}')"
        fi
        sed -i "s/nid=$NID/nid=$NID $ESTR/" $TMP_DIR/stack-$TRACETIME.out
    done
    sleep $TRACE_INTERVAL
done