zfs discuss - Apr 2008 - how to measure in kernel how much time one operation takes

what call to be used in kernel to measure time taken for a operation if time
quantum i s smaller than tick(frequency).
i tried using ddi_get_lbolt  at time t1 and t2.(at time t1 operation started and
t2 it finished) but it always gives me zero(t2-t1).
 
 
This message posted from opensolaris.org

shri wrote:
> what call to be used in kernel to measure time taken for a operation if
time quantum i s smaller than tick(frequency).
> i tried using ddi_get_lbolt  at time t1 and t2.(at time t1 operation
started and t2 it finished) but it always gives me zero(t2-t1).
>  
>   
Try get hi-res time, gethrtime()
http://docs.sun.com/app/docs/doc/816-5180/gethrtime-9f?a=view
 -- richard

could you perhaps use dtrace?

I think it is a nanoseconds time you have there.

  Henry

On Sat, Apr 19, 2008 at 1:50 AM, shri <agshriram at yahoo.com> wrote:
> what call to be used in kernel to measure time taken for a operation if
> time quantum i s smaller than tick(frequency).
> i tried using ddi_get_lbolt  at time t1 and t2.(at time t1 operation
> started and t2 it finished) but it always gives me zero(t2-t1).
>
>
> This message posted from opensolaris.org
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