Jiffies from userspace

Jiffies from userspace

[Jim]

 Sorry if this question seems stupid, but would this be a 
 reasonable way to get an estimate of the "current" value of the 
 kernel's jiffies:

 	set -- `cat /proc/self/stat`; echo ${22}

 ... my reasoning:

 The cat will start a new process, field 22? of its "stat" node 
 under proc should have the jiffies value at the time the process
 was started; so the echo command execute "shortly" thereafter.

 But am I right about the struct of stat:  Is that really in ${22}?

 (I'm not actually planning on using this technique, it's just a
  curiosity.  The only practical use I can see for it might be for 
  doing a sanity check on gettime; checking this for an increasing 
  value has a hedge against settime discontinuities).

 knfsd: follow symlinks?

 Also, an unrelated question:  is there a way to get the knfsd to
 resolve symlinks on the server side?  (Basically to configure it
 such that it doesn't present symlinks on the underlying fs as 
 symlinks to the client --- but rather it internally follows them,
 and presents the target link/inode data to network clients).  ISTR
 that the older user nfsd used to have some option like that.
 (I realize this second question would be better posed as a separate
 message; oh well).

--
Jim Dennis 

Re: Jiffies from userspace

[Eli Carter]

Jim wrote:
> 
>  Sorry if this question seems stupid, but would this be a
>  reasonable way to get an estimate of the "current" value of the
>  kernel's jiffies:
> 
>         set -- `cat /proc/self/stat`; echo ${22}
> 
>  ... my reasoning:
> 
>  The cat will start a new process, field 22? of its "stat" node
>  under proc should have the jiffies value at the time the process
>  was started; so the echo command execute "shortly" thereafter.
> 
>  But am I right about the struct of stat:  Is that really in ${22}?
> 
>  (I'm not actually planning on using this technique, it's just a
>   curiosity.  The only practical use I can see for it might be for
>   doing a sanity check on gettime; checking this for an increasing
>   value has a hedge against settime discontinuities).

'cat /proc/uptime' might be more what you want...

Eli
--------------------.     Real Users find the one combination of bizarre
Eli Carter           \ input values that shuts down the system for days.
eli.carter(a)inet.com `-------------------------------------------------

Re: Jiffies from userspace

[Mark Zealey]

On Fri, Feb 01, 2002 at 12:33:21PM -0800, Jim wrote:

> 
>  Sorry if this question seems stupid, but would this be a 
>  reasonable way to get an estimate of the "current" value of the 
>  kernel's jiffies:
> 
>  	set -- `cat /proc/self/stat`; echo ${22}
> 
>  ... my reasoning:
> 
>  The cat will start a new process, field 22? of its "stat" node 
>  under proc should have the jiffies value at the time the process
>  was started; so the echo command execute "shortly" thereafter.

Maybe, another idea would be to look at /proc/interrupts, on the timer one
(IRQ0)...

-- 

Mark Zealey
mark@zealos.org
mark@itsolve.co.uk

UL++++>$ G!>(GCM/GCS/GS/GM) dpu? s:-@ a16! C++++>$ P++++>+++++$ L+++>+++++$
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(www.geekcode.com)

Re: Jiffies from userspace

[Athanasius]

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On Fri, Feb 01, 2002 at 12:33:21PM -0800, Jim wrote:
>  reasonable way to get an estimate of the "current" value of the 
>  kernel's jiffies:
> 
>  	set -- `cat /proc/self/stat`; echo ${22}
> 
>  The cat will start a new process, field 22? of its "stat" node 
>  under proc should have the jiffies value at the time the process
>  was started; so the echo command execute "shortly" thereafter.
> 
>  But am I right about the struct of stat:  Is that really in ${22}?

   Assuming so try:

	awk '{print $22}' /proc/self/stat

for a 'single process' version.

-Ath
-- 
- Athanasius = Athanasius(at)gurus.tf / http://www.clan-lovely.org/~athan/
                  Finger athan(at)fysh.org for PGP key
	   "And it's me who is my enemy. Me who beats me up.
Me who makes the monsters. Me who strips my confidence." Paula Cole - ME

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