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I’ll show two tips here on how to check a process’ running time, it’s very helpful for system administrators to know these tips as they may need to clean some abnormal processes. It’s a common issue when using FastCGI with apache.

The first one can be used to examine the start time of a specified process:

[mail@iwork ~]$ ps -ef| grep perl
mail  3495  3324  0  2008 ?        00:00:00 /usr/bin/perl /home/mail/msodisk
[mail@iwork ~]$ ls -ld /proc/3495
dr-xr-xr-x  3 mail mail 0 Oct 10 01:03 /proc/3495/

Here, “Oct, 10 01:03” is the process starting time, please note that, this command only works on 2.6 kernels, when
using it on kernel-2.4 system, the timestamp “Oct, 10 01:03” would be replaced by current system time.

The second express can be used on both 2.4 kernel and 2.6 kernels:

expr $(awk -F. '{print $1}' /proc/uptime) - $(expr $(awk '{print $22}' /proc/${PID}/stat) / 100)

Before using this command, you need to set ${PID}. The following section shows an example:

[mail@cluster90 mail]$ ps -auxxf | grep crawler
mail   813  0.0  0.0  2076  816 ?        SN    2007 550:16 bin/crawler
mail   814  0.0  0.0  2144  756 ?        SN    2007  57:55  _ bin/crawler
[mail@cluster90 mail]$ PID=813
[mail@cluster90 mail]$ expr $(awk -F. '{print $1}' /proc/uptime) - $(expr $(awk '{print $22}' /proc/${PID}/stat) / 100)
39764575

As you see, on this server, the admon’s client-side agent “crawler” has been running for more that one year…… and eat only 1.5MB memory in total.

Acturally, we have had crawler running for more that 2.5 years without any termination and exceptions.

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