From: Tom Lane <tgl@sss.pgh.pa.us>
To: Hannu Krosing <hannuk@google.com>
cc: Peter Eisentraut <peter@eisentraut.org>,
        "Andrey M. Borodin" <x4mmm@yandex-team.ru>,
        pgsql-hackers <pgsql-hackers@postgresql.org>
Subject: Re: What is a typical precision of gettimeofday()?
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Comments: In-reply-to Hannu Krosing <hannuk@google.com>
	message dated "Tue, 02 Jul 2024 19:31:21 +0200"
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Date: Tue, 02 Jul 2024 13:50:13 -0400
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Hannu Krosing <hannuk@google.com> writes:
> Also, reading directly in ticks on M1 gave "loop time including
> overhead: 2.13 ns" (attached code works on Clang, not sure about GCC)

I don't think we should mess with that, given the portability
problems you mentioned upthread.

> I'll also take a look at the docs and try to propose something

OK.

> 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.

			regards, tom lane

[1] https://coverage.postgresql.org/src/bin/pg_test_timing/pg_test_timing.=
c.gcov.html