Converting from jiffies to ticks
jessefrgsmith at yahoo.ca
Thu Aug 19 19:16:05 UTC 2010
I am currently trying to port a program from Linux to FreeBSD which
detects how much processor time a process is using. The native Linux
code does this (in part) by reading the number of "jiffies" a given
process uses. This info is pulled from the /proc/PID/stat file.
One function is failing on FreeBSD and it's obviously because FreeBSD
does not have all the same files/data in the /proc directory.
I've looked around and, as I understand it, FreeBSD uses "ticks" instead
of "jiffies" to measure process usage. However, how to gather that data
is a bit lost on me.
This raises two questions for me:
1. Where can I find the equivalent information on FreeBSD? I assume
there's a function call. Maybe in the kvm_* family? I need to be able to
get the number of ticks a given PID is using.
2. Any idea on what the conversion rate between ticks and jiffies is?
Are they the same thing, but with different names? Or is it a kilometres
and miles issue?
The rest of the program measures everything in "jiffies", so it would be
ideal for me to get the ticks used on FreeBSD (based on PID), convert it
to "jiffies" and pass it back to the main program.
Thanks for any advise,
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