Re: [patch 2/2] timerfd extend clockid support

From: Michael Kerrisk
Date: Mon Feb 09 2009 - 14:28:21 EST


On Tue, Feb 10, 2009 at 6:42 AM, Davide Libenzi <davidel@xxxxxxxxxxxxxxx> wrote:
> On Mon, 9 Feb 2009, Michael Kerrisk wrote:
>
>> On Mon, Feb 9, 2009 at 12:23 PM, Davide Libenzi <davidel@xxxxxxxxxxxxxxx> wrote:
>> > The following patch extends timerfd clockid support to cover the ones
>> > supported by timer_create().
>> > It exports the invalid_clockid() function outside posix-timers.c to allow
>> > timerfd to properly check input parameters.
>> > Andrew, this is (eventually) .30 material, and do not take the patch
>> > until you have Thomas sign off.
>> > Thomas, timerfd uses core hrtimer functions for its tasks. By extending
>> > the clockid support, I assume that the clockids other than CLOCK_MONOTONIC
>> > and CLOCK_REALTIME, behaves the same from a hrtimer caller POV. Right?
>>
>> Hi Davide,
>>
>> Have you done any testing of this patch? My attempts at testing with
>> clocks other than REALTIME and MONOTONIC all don't work so far. In
>> some cases, my test programs causes the system to hang. Try
>> experimenting with the (not yet well tested) test program below, to
>> check the behavior with other clocks.
>
> Michael, no I did not test it

Yep -- I realised afterwards that you had already said that...

> and I did not have even the time to peek
> into the core timer code to see if the usage of other timer types in
> eventfd would create problems. That's why I asked Thomas if they'd behave
> differently from an hrtimer caller POV.
> I'll try to take a look by myself today or tomorrow.

Okay -- hopefully my test program may be useful (even if it is not
itself fully tested yet, it's patterned after a similar test program I
wrote fot the POSIX timers API, so it should mostly work).

--
Michael Kerrisk
Linux man-pages maintainer; http://www.kernel.org/doc/man-pages/
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