Correction ...
On 19/05/2017 8:53 PM, David Holmes wrote:
On 19/05/2017 7:25 PM, Robbin Ehn wrote:
On 05/19/2017 11:07 AM, David Holmes wrote:
They have to be as there are three cases:
1. Relative wait using CLOCK_MONOTONIC
2. Relative wait using gettimeofday()
3. Absolute wait using gettimeofday()
Please consider something like:
#ifdef SUPPORTS_CLOCK_MONOTONIC
if (_use_clock_monotonic_condattr && !isAbsolute) { // Why
aren't we using this when not isAbsolute is set?
// I suggest removing that check
from this if and use monotonic for that also.
Absolute waits have to be based on wall-clock time and follow any
adjustments made to wall clock time. In contrast relative waits
should never be affected by wall-clock time adjustments hence the use
of CLOCK_MONOTONIC when available.
In Java the relative timed-waits are:
- Thread.sleep(ms)
- Object.wait(ms)/wait(ms,ns)
- LockSupport.parkNanos(ns) (and all the j.u.c blocking methods built
on top of it)
While the only absolute timed-wait we have is the
LockSupport.parkUntil method(s).
Hope that clarifies things.
Yes thanks!
But you can still re-factoring to something similar to what I
suggested and two of the calculation should be the same just ns vs us,
correct?
There are three different forms of the calculation. The two relative
time versions use a different time function and so a different time
structure (timeval vs timespec) and a different calculation.
Leaving the if statement with the "!isAbsolute" check, in my head
calc_time is something like:
void calc_time(...) {
if (isAbsolute) {
calc_abs_time(...);
} else {
#ifdef SUPPORTS_CLOCK_MONOTONIC
calc_rel_time_from_clock_monotonic(...);
#else
> calc_rel_time_from_gettimeofday(...);
#endif
}
}
It's more complicated than that because we may have build time
SUPPORTS_CLOCK_MONOTONIC but we still need the runtime check as well.
to_abstime is the old linux unpackTime with the addition of the build
time conditionals.
David
David
-----
I do not see a problem with this, only better readability?
/Robbin
Thanks,
David
-----
struct timespec now;
int status = _clock_gettime(CLOCK_MONOTONIC, &now);
assert_status(status == 0, status, "clock_gettime");
calc_time(abstime, timeout, isAbsolute, now.tv_sec,
now.tv_nsec, NANOUNITS);
} else {
#else
{
#endif
struct timeval now;
int status = gettimeofday(&now, NULL);
assert(status == 0, "gettimeofday");
calc_time(abstime, timeout, isAbsolute, now.tv_sec,
now.tv_usec, MICROUNITS);
}
#endif
Thanks for fixing this!
/Robbin
