Re: CPU usage inaccuracy for taskqueue

--- On Sun, 3/1/09, Barney Cordoba <barney_cordoba_at_yahoo.com> wrote:

> From: Barney Cordoba <barney_cordoba_at_yahoo.com>
> Subject: Re: CPU usage inaccuracy for taskqueue
> To: current_at_freebsd.org
> Date: Sunday, March 1, 2009, 10:46 AM
> --- On Sun, 3/1/09, Barney Cordoba
> <barney_cordoba_at_yahoo.com> wrote:
> 
> > From: Barney Cordoba <barney_cordoba_at_yahoo.com>
> > Subject: CPU usage inaccuracy for taskqueue
> > To: current_at_freebsd.org
> > Date: Sunday, March 1, 2009, 10:22 AM
> > I've been playing with the ige driver and as a
> test
> > shifted the entire
> > receive load to a task instead of doing it in the
> msix_rx
> > routine by simply
> > launching a receive task whenever an interrupt is
> > generated. When doing so 
> > and applying a moderate load, top readings show:
> > 
> > PID USERNAME  THR PRI NICE   SIZE    RES STATE  C  
> TIME  
> > WCPU COMMAND   11 root        1 171 ki31     0K     8K
> RUN  
> >  3   6:31 100.00% idle: cpu3  12 root        1 171
> ki31    
> > 0K     8K CPU2   2   6:30 100.00% idle: cpu2  13 root 
>      
> > 1 171 ki31     0K     8K CPU1   1   6:29 100.00% idle:
> cpu1
> > 14 root        1 171 ki31     0K     8K CPU0   0  
> 6:23
> > 99.17% idle: cpu0
> > 42 root        1 -68    -     0K     8K -      0  
> 0:07 
> > 7.47% igb1 taskq
> > 
> > clearly the cpu idle thread values aren't correct.
> This
> > is the case in
> > both 7.0 and 7.1. Since the point of my testing is to
> > experiment with 
> > schemes for spreading loads better, I'm not able
> to
> > learn anything with
> > the lack of usable feedback. Is there a simple fix?
> > 
> > Barney
> 
> 
> Sorry for the ugly post. It looks ok in Yahoo and then gets
> all jumbled.
> The gist of the top output:
> 
>  100.00% idle: cpu3
>  100.00% idle: cpu2
>  100.00% idle: cpu1
>   99.17% idle: cpu0
>    7.47% igb1 taskq
> 
> The task is show 7.5% usage and < 1% usage is shown by
> the cpu idle
> threads.
> 
> Barney
> 

Can someone point me to the module / source file where this accounting
*should* take place?

BC