How do you find the age of a long-running Linux process?

Question

I have a problem with some zombie-like processes on a certain server that need to be killed every now and then. How can I best identify the ones that have run for longer than an hour or so?

Answer 1

Using ps is the right way. I've already done something similar before but don't have the source handy. Generally - ps has an option to tell it which fields to show and by which to sort. You can sort the output by running time, grep the process you want and then kill it.

HTH

Answer 2

For anything older than one day,

ps aux

will give you the answer, but it drops down to day-precision which might not be as useful.

USER       PID %CPU %MEM    VSZ   RSS TTY      STAT START   TIME COMMAND
root         1  0.0  0.0   7200   308 ?        Ss   Jun22   0:02 init [5]
root         2  0.0  0.0      0     0 ?        S    Jun22   0:02 [migration/0]
root         3  0.0  0.0      0     0 ?        SN   Jun22   0:18 [ksoftirqd/0]
root         4  0.0  0.0      0     0 ?        S    Jun22   0:00 [watchdog/0]

If you're on linux or another system with the /proc filesystem, In this example, you can only see that process 1 has been running since June 22, but no indication of the time it was started.

stat /proc/<pid>

will give you a more precise answer. For example, here's an exact timestamp for process 1, which ps shows only as Jun22:

ohm ~$ stat /proc/1
  File: `/proc/1'
  Size: 0               Blocks: 0          IO Block: 4096   directory
Device: 3h/3d   Inode: 65538       Links: 5
Access: (0555/dr-xr-xr-x)  Uid: (    0/    root)   Gid: (    0/    root)
Access: 2008-06-22 15:37:44.347627750 -0700
Modify: 2008-06-22 15:37:44.347627750 -0700
Change: 2008-06-22 15:37:44.347627750 -0700

Answer 3

Found an answer that works for me:

ps -eo uid,pid,etime | egrep '^ *user-id' | egrep ' ([0-9]+-)?([0-9]{2}:?){3}' | awk '{print $2}' | xargs -I{} kill {}

(Where user-id is a specific user's ID with long-running processes.)

The second regular expression matches the a time that has an optional days figure, followed by an hour, minute, and second component, and so is at least one hour in length.

Answer 4

In this way you can obtain the list of the ten oldest processes:

ps -elf | sort -r -k12 | head -n 10

Answer 5

do a ps -aef. this will show u the time at which the process started. Then using the date command find the current time. Calculate the difference between th two to find the age of the process.

Thanks, Maniraj Patri

Answer 6

I've been tinkering with the answer posted by yukondude with little success. I'm trying to kill processes that are older than 10 minutes. I already know what the process IDs are. I'm looping over an array every 10 min to see if any lingering procs are around and need to be killed. Anybody have any quick thoughts on this?

Thanks, Steve

Answer 7

Perl's Proc::ProcessTable will do the trick: http://search.cpan.org/dist/Proc-ProcessTable/

You can install it in debian or ubuntu with sudo apt-get install libproc-processtable-perl

Here is a one-liner:

perl -MProc::ProcessTable -Mstrict -w -e 'my $anHourAgo = time-60*60; my $t = new Proc::ProcessTable;foreach my $p ( @{$t->table} ) { if ($p->start() < $anHourAgo) { print $p->pid, "\n" } }'

Or, more formatted, put this in a file called process.pl:

#!/usr/bin/perl -w
use strict;
use Proc::ProcessTable;
my $anHourAgo = time-60*60;
my $t = new Proc::ProcessTable;
foreach my $p ( @{$t->table} ) {
    if ($p->start() < $anHourAgo) {
        print $p->pid, "\n";
    }
}

then run perl process.pl

This gives you more versatility and 1-second-resolution on start time.