Re: Tesing of / bugs in new timerfd API

From: Michael Kerrisk
Date: Mon Dec 17 2007 - 08:27:44 EST


Hi Davide,

On 12/16/07, Davide Libenzi <davidel@xxxxxxxxxxxxxxx> wrote:
> On Fri, 14 Dec 2007, Michael Kerrisk wrote:
>
> > You snipped my example that demonstrated the problem. Both of the
> > following runs create a timer that expires 10 seconds from "now", but
> > observe the difference in the value returned by timerfd_gettime():
> >
> > $ ./timerfd_test 10 # does not use TFD_TIMER_ABSTIME
> > Initial setting for settime: value=10.000, interval=0.000
> > ./timerfd_test> g
> > (elapsed time= 1)
> > Current value: value=346.448, interval=0.000
> >
> > $ ./timerfd_test -a 10 # uses TFD_TIMER_ABSTIME
> > Initial setting for settime: value=1197630855.254, interval=0.000
> > ./timerfd_test> g
> > (elapsed time= 1)
> > Current value: value=1197630855.254, interval=0.000
> >
> > Either there's an inconsistency here depending on the use of
> > TFD_TIMER_ABSTIME, or there is a bug in my understanding or my test
> program
> > (but so far I haven't spotted that bug ;-).).
>
> Can you try the two patches below? I tried them on my 32 bit box (one of
> the rare beasts still lingering around here) and it seems to be working
> fine (those go on top of the previous ones).

Against 2.6.24-rc5, I applied first your earlier patches ("v3") and
then the newest patch. My tests confirm that:

> This fixed the 32 bit tick-count truncation, and makes the time returned
> to be the remaining time till the next expiration.

Are you going to resubmit a new patch set that includes these latest changes?

Michael
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/