I'm creating a plugin for Munin to monitor stats of named processes. One of the sources of information would be /proc/[pid]/io
. But I have a hard time finding out what the difference is between rchar
/wchar
and read_bytes
/written_bytes
.
They are not the same, as they provide different values. What do they represent?
While the proc manpage is woefully behind (and so are most manpages/documentation on anything not relating to cookie-cutter user-space development), this stuff is fortunately documented completely in the Linux kernel source under
Documentation/filesystems/proc.txt
. Here are the relevant bits: