I have set ITIMER_REAL On Sun, Oct 24, 2010 at 4:57 AM, Vimal <j.vi...@gmail.com> wrote:
> Hi Prabhu, > > On 21 October 2010 23:56, Prabhu nath <gprabhun...@gmail.com> wrote: > > Dear All, > > > > > > 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. > > Have you set a virtual time interrupt (ITIMER_VIRTUAL) or real timer > 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 >
