Understanding ps elapsed time format for long running processes

Question

I'm using a ps command as part of an exercise to identify processes running longer than a given threshold.

I'm using the following template to get the elapsed time for a know process command:

ps -eo etime,command | grep <something to identify a process> | grep -v grep | awk '{print $1}'

I notice with short-running processes, the etime (elapsed time) value takes the format minutes:seconds and from this I can easily determine how long a process has been running.

For very long running processes (days long), I don't understand the format.

I have a MySQL server process that htop shows as running for 126 hours.

Executing ps -eo etime,command | grep mysql | grep -v grep | awk '{print $1}' gives me a value of 9-03:35:32.

My best guess is that this means 9 something, 3 hours, 35 minutes, 32 seconds. I can't figure out what the units are for the 9.

The process in question has been running 126 hours, about 5.25 days. This suggests that the 9 in the above output does not represent days. They can't be half days either as (9 * 12) hours + 3 hours + 35 minutes + 32 seconds is less than 5 days.

How do I interpret the elapsed time value I am seeing for long-running processes? What units accompany the 9 in the above output?

Here, you're seeing the POSIX time format. Minutes:seconds is the BSD time format. Linux's ps displays one or the other depending on the options you pass. — Gilles 'SO- stop being evil', Nov 01 '12 at 17:22
To double-check, try etimes instead of etime and compare the results. — Ruslan, Jul 29 '18 at 19:34

score 19 · Accepted Answer · edited Dec 08 '16 at 21:13

19

According to the standard:

In the POSIX locale, the elapsed time since the process was started, in the form:
[[dd-]hh:]mm:ss
where dd shall represent the number of days, hh the number of hours, mm the number of minutes, and ss the number of seconds. The dd field shall be a decimal integer. The hh, mm, and ss fields shall be two-digit decimal integers padded on the left with zeros.

So, the 9 means days, whether you believe it or not. Could you be misinterpreting the output from htop? What does top (which has a time format of minutes:seconds) say? Are you certain that the field you are looking at in htop is equivalent to etime? (for example, could it means 126 minutes of CPU time?)

edited Dec 08 '16 at 21:13

Janus Troelsen

1,493

answered Nov 01 '12 at 12:07

Random832

10,666

Thanks for the confirmation. htop is definitely showing 126 hours, but I think this might not be wall time but some other time (perhaps CPU time). The field in htop is not equivalent to etime, I assumed wrongly here. – Jon Cram Nov 01 '12 at 12:18
1

@JonCram Are you sure it's hours? Original top only shows minutes (i.e. it will go to minutes above 60 rather than breaking up to hours), a number like 126:37 means 126 minutes and 37 seconds. I was thinking htop might be the same. 126 hours of CPU time in 9 days seems like a lot. – Random832 Nov 01 '12 at 12:20

Understanding ps elapsed time format for long running processes

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