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From: Hannu Krosing <hannuk@google.com>
Date: Tue, 2 Jul 2024 20:15:59 +0200
Message-ID: <CAMT0RQQXzkL=QREKtu1esiNbD5k0ULJF9Jb2fgBuYOJSwegpPA@mail.gmail.com>
Subject: Re: What is a typical precision of gettimeofday()?
To: Tom Lane <tgl@sss.pgh.pa.us>
Cc: Peter Eisentraut <peter@eisentraut.org>, "Andrey M. Borodin" <x4mmm@yandex-team.ru>, 
	pgsql-hackers <pgsql-hackers@postgresql.org>
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On Tue, Jul 2, 2024 at 7:50=E2=80=AFPM Tom Lane <tgl@sss.pgh.pa.us> wrote:
>

> > Do we also need tests for this one ?
>
> Yeah, it was annoying me that we are eating the overhead of a TAP test
> for pg_test_timing and yet it covers barely a third of the code [1].
> We obviously can't expect any specific numbers out of a test, but I
> was contemplating running "pg_test_timing -d 1" and just checking for
> (a) zero exit code and (b) the expected header lines in the output.

At least "does it run" tests should be there -

For example with the current toolchain on MacOS I was able to compile
__builtin_readcyclecounter(); but it crashed when the result was
executed.

The same code compiled *and run* fine on same laptop with Ubuntu 24.04

We might also want to have some testing about available speedups from
pg_bitmanip.h being used, but that could be tricky to test in an
universal way.

--
Hannu