On Sun, Oct 24, 2010 at 4:57 AM, Vimal <j.vimal@xxxxxxxxx> wrote:
Hi Prabhu,
On 21 October 2010 23:56, Prabhu nath <gprabhunath@xxxxxxxxx> wrote:
> Dear All,
>Have you set a virtual time interrupt (ITIMER_VIRTUAL) or real timer
>
> There is a time difference t between the time t1-at which the pending signal
> is set and the time t2-at which exact signal handler is executed.
>
> Question: I need to calculate the time difference between t1 and t2.
interrupt (ITIMER_REAL)?
There are two components here: scheduler latency and the timer
interrupt latency. Both add up to the latency perceived by the
userspace program. Which one do you want to measure?
If you're interested in the end latency and if you've set a
ITIMER_REAL timer, it's pretty easy to measure the latency upto some
precision. Before setting the timer, note the 'start' real time using
gettimeofday. After the timer handler (after time interval dt) fires,
note the real time 'end'. (end-start) - dt should be the required
latency.
--
Vimal
