turning a /proc/$pid/stat startTime into "seconds since this process started"

[andrew.geo...@gmail.com]

I want to find out how long a process has been running.

I'm grabbing the starttime out of /proc/$pid/stat for a process. This is in "in clock ticks (divide by sysconf(_SC_CLK_TCK))." according to http://man7.org/linux/man-pages/man5/proc.5.html

I also have Sysinfo.Uptime (seconds since boot). My plan was to subtract proc starttime from uptime, but I need to first divide out the clock tick / second to get my units right. I haven't been able to find a way to get this value.

I suspect that my approach is wrong and that there is probably a more elegant way to do this.

A

[Caleb Spare]

You can do it with cgo. I have some code that does this:

// #include <unistd.h>
import "C"

func init() {
clockTicksPerSec = float64(C.sysconf(C._SC_CLK_TCK))
if clockTicksPerSec != 100 {
log.Println("Unusual _SC_CLK_TCK value:", clockTicksPerSec)
}
}

var clockTicksPerSec float64

// later it normalizes things by clickTicksPerSec

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[Andrew Hammond]

I punted and just did clockTicksPerSecond := float64(100) since I couldn't get this to build correctly. It's supposed to be a statically linked binary in a docker scratch container. Close enough, I guess.