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/proc/<pid>/stat children CPU time

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http://serverfault.com – I've been running the following command on my linux box: watch -d -n 1 "cat /proc/19866/stat" The pid above is a pid of Nginx's master process - I would expect the following fields to be changing: 14, 15, 16 and 17 as according to kernel docs those should contain amount of time the process has been scheduled in user/kernel mode (14,15) and its children too (16,17), however running this command in watch I noticed that none of those numbers ever change. Can someone shed a bit more light on this ? I'd like to count some CPU usage stats per process and I thought /proc.. was the place to look. T (HowTos)

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Submitted by u85500 on 01/06/2013

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When I try to calculate the cpu usage by parse out the data from /proc/<PID>/stat, I meet a problem.Firstly ,for each process I calculate the cpu usage % with below manner:prb_time = utime+stime; the utime and stime is from the file /proc/<PID>/stat. After 2 seconds calculate the prb_time again.

I know that jiffies length is selected at kernel compile time and it is defaulted to 250 (4ms). Source: man 7 time - The Software Clock, HZ, and Jiffies

I wonder what happens inside a jiffy. What are the conditions to increase the value of utime or stime in /proc/pid/stat?

I know that jiffies length is selected at kernel compile time and it is defaulted to 250 (4ms). Source: man 7 time - The Software Clock, HZ, and Jiffies

I wonder what happens inside a jiffy. What are the conditions to increase the value of utime or stime in /proc/pid/stat?

I'm executing a basic C program using gdb. I have a break point at the start of main(). After running the code, gdb breaks at main() as expected. Now if I examine the stack pointer register (rsp), i'm seeing

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I'm using /proc/stat to calculate system cpu usage. Lately, I've been occasionally seeing strange events where the cpu line entries aren't monotonic.

e.g.

I'm trying to read /proc/$pid/mem file. It's another process run by the same user. File permissions seems to be sufficient. But still I'm getting this:

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I found this snippet: http://lxr.linux.no/#linux+v2.6.37/fs/proc/base.c#L197 But it dissapeared in 3.x kernels.

I was tinkering around with the /proc filesystem in Linux, and I came across /proc/self, which is a symbolic link to the process directory of the current process. I would like to know how it is implemented. One solution would be to change that symlink on every context switch, but that's obviously very expensive as it involves a disk access.

Linux stat Command 2 years 2 weeks ago

Tweetstat The stat utility allows you to see all information about either a file or a directory.  You can use wildcards if you want to see info for more than one object at a time. stat process.sh...

I'm trying to trigger a reload of the nginx master process by using pkill and sudo. The server reloads fine, but I was just curious if anyone knows why the command `sudo pkill -HUP -f "nginx: master process" returns code 129.

# Running as root $ pkill -HUP -f "nginx: master process" $ echo $?

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