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Home > Archive > Unix Programming > February 2006 > process accounting
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process accounting
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| varma.iitb@gmail.com 2006-02-23, 2:54 am |
| I have a small doubt regarding process times. I am reading process
information from /proc file system. There are utime, stime, cutime and
cstime. To get the total process time do i have to add utime, stime
(utime+stime) or i have to add all 4 (utime+stime+cutime+cstime).
Suppose process A spawns a new process B, assume both are running now,
if I read times of both processes. Is process B time included in
process A or not.
And,
I switched on process accounting using acct system call. Now process A
is started and after some time it spawns process B, now both are
running. after some time both processes exited. So process records
corresponding to A & B will be written to accounting file. When I read
utime, stime of A & B , will B times are included in A or not.
Thanks
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| loic-dev@gmx.net 2006-02-26, 10:16 am |
| Hello,
> I have a small doubt regarding process times. I am reading process
> information from /proc file system. There are utime, stime, cutime and
> cstime. To get the total process time do i have to add utime, stime
> (utime+stime) or i have to add all 4 (utime+stime+cutime+cstime).
utime = time spent so far in user space by the process
stime = time spent so far in kernel space by the process
cutime = time spent in user space by the terminated child processes
cstime = time spent in kernel space by the terminated child processes.
The answer to your questions follow from the above definitions.
Cheers,
Loic.
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| varma.iitb@gmail.com 2006-02-26, 10:16 am |
|
loic-dev@gmx.net wrote:
> Hello,
>
>
> utime = time spent so far in user space by the process
> stime = time spent so far in kernel space by the process
> cutime = time spent in user space by the terminated child processes
> cstime = time spent in kernel space by the terminated child processes.
> The answer to your questions follow from the above definitions.
Thanks. I have a doubt. Actually when I read process times from /proc
filesystem as well as using "acct" system call, I am getting process
times in jiffies. Is jiffies is the smaller unit of measurement in
linux, it's not right?.
I have written a program with times function at start and end of the
program. I started process accounting on using acct. and I executed my
program, it displays process times in clock_t (big numbers). And I
turned process accounting off. I read accounting file. The process
times are (utime and stime) zero jiffies. But here we are losing the
actual time.
I have seen kernel source. It actually converting clock_t to jiffies.
How can I get clock_t value.
>
> Cheers,
> Loic.
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