Re: [HACKERS] gettimeofday is at the end of its usefulness?

Andres Freund <andres@anarazel.de> writes:
> On 2016-12-27 01:35:05 +0000, Greg Stark wrote:
>> On Dec 26, 2016 10:35 PM, "Tom Lane" <tgl@sss.pgh.pa.us> wrote:
>>> So it seems like the configure support we'd need is to detect
>>> whether clock_gettime is available (note on Linux there's also
>>> a library requirement, -lrt), and we would also need a way to
>>> provide a platform-specific choice of clockid; we at least need
>>> enough smarts to use CLOCK_MONOTONIC_RAW on macOS.

>> This seems like something that really should be checked at runtime.

> I'm pretty strongly against doing performance measurements at
> startup. Both the delay and the potential for differing test results
> seem like pretty bad consequences.

Yeah, that doesn't sound great to me either.  And I don't entirely
see the point, at least not with what we know now.  I am a bit concerned
that we'll find out there are popular platforms where clock_gettime
compiles but fails with ENOSYS, or some similarly unhelpful behavior.
But we won't find that out if we don't try.
        regards, tom lane