Re: [PATCH 6/7] nptl/tst-rwlock: Use clock_gettime/timespec rather than gettimeofday/timeval

[Mike Crowe <mac at mcrowe dot com>]

On Tuesday 05 March 2019 at 15:02:21 -0300, Adhemerval Zanella wrote:
> On 27/02/2019 15:23, Mike Crowe wrote:
> > In preparation for adding pthread_rwlock_clockrdlock and
> > pthread_rwlock_clockwrlock, convert various tests to only use clock_gettime
> > and struct timespec.
> > 
> > * support/timespec.h: Create header to provide timespec helper functions
> >   from sysdeps/pthread/posix-timer.h for tests to use.
> > 
> > * nptl/tst-rwlock6.c: Fix small bug in timeout-checking code that could
> >   erroneously pass if the function incorrectly took more than a second.
> > 
> > * nptl/tst-rwlock6.c: Use clock_gettime(2) rather than gettimeofday(2) and
> >   then converting to timespec in preparation for testing
> >   pthread_rwlock_clockrdclock and pthread_rwlock_clockwrlock.
> > 
> > * nptl/tst-rwlock9.c, nptl/tst-rwlock7.c: Likewise.
> 
> I am seeing this issue sporadically on i686-linux-gnu with 6/7 patches
> applied:
> 
> $ ./testrun.sh nptl/tst-rwlock7 --direct
> 0: got timedrdlock
> child: timedwrlock failed with ETIMEDOUT
> child: timedwrlock failed with EINVAL
> 1: got timedrdlock
> child: timedwrlock failed with ETIMEDOUT
> child: timedwrlock failed with EINVAL
> 2: got timedrdlock
> child: timedwrlock failed with ETIMEDOUT
> 2nd timedwrlock did not return EINVAL
> failure in round 2

Sorry, I hadn't spotted this part of your email until today. Luckily it's
clear what I got wrong and why I didn't see it on AArch64 and x86_64:

> > +  struct timespec ts_invalid;
> > +  (void) clock_gettime (CLOCK_REALTIME, &ts_invalid);
> > +  ts_invalid.tv_sec += 10;
> >    /* Note that the following operation makes ts invalid.  */
> > -  ts.tv_nsec += 1000000000;
> > +  ts_invalid.tv_nsec += 1000000000000;

I got so used to converting from µs to ns that I added three extra zeroes
unnecessarily here. It fits in a 64-bit long, but not a 32-bit one.

Thanks. I shall do more testing on 32-bit targets.

Mike.