Re: recovery test failure on morepork with timestamp mystery

Hi,

On 2022-05-13 09:00:20 +0200, Mikael Kjellström wrote:
> Well, I don't know if you remember but there was a thread a while back and a
> test program (monotime.c) to test the clock if it could go backwards and
> openbsd showed the following result when running the attached testprogram:

Nope, didn't remember...

> $ ./monotime
> 410310 Starting
> 547727 Starting
> 410310 Back 262032.372314102 => 262032.242045208
> 410310 Stopped
> 465180 Starting
> 255646 Starting
> 547727 Stopped
> 465180 Stopped
> 255646 Stopped
>
> could that have something to do with it?

Yes!

> printf("%d Back %lld.%09lu => %lld.%09lu\n",
> (int)getthrid(), ts0.tv_sec, ts0.tv_nsec, ts1.tv_sec,
> ts1.tv_nsec);
> break;

I wonder whether the %09lu potentially is truncating ts1.tv_nsec.

I can't reproduce the problem trivially in an openbsd VM I had around. But
it's 7.1, so maybe that's the reason?

Greetings,

Andres Freund