fyi, with respect to using the start time to uniquely identify a process.
It turns out that on Linux[1] looking at st_mtime from
stat(/proc/pid/status)
doesn't always produce the same value (and the inode number can change).
When spawning large number of processes (< 500)
it appears the pseudo inode entries are not kept around and are
re-initialized.
In a brief peek at the Linux code in fs/proc/inode.c it appears always
to initialize
st_mtime/st_atime/st_ctime from the current time.
It seems a slightly more expensive read and parse of the file will be
needed
to get and check the start time.
fyi, Roger
[1] Ubuntu 14.04. (Linux-3.13.0) sources
On 4/17/2015 4:05 AM, Peter Levart wrote:
At least on Linux (/proc/<pid>/stat) and Solaris (/proc/<pid>/status)
it is not necessary to open those special files and read them. Just
doing stat() on them and using the st_mtime will get you the process
start time. I see AIX shares native code with Linux (unix), so perhaps
AIX does the same. Mac OSX and Windows have special calls...
