Horton

Re: What is a typical precision of gettimeofday()?

Tom Lane <tgl@sss.pgh.pa.us>

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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>
Date: 2024-07-02T17:50:13Z
Lists: pgsql-hackers

Commits

Same data as JSON: GET /api/v1/messages/:b64id/commits the thread's linked commits as JSON, with link sources. API reference →

  1. Force LC_NUMERIC to C while running TAP tests.

  2. Minor tweaks for pg_test_timing.

  3. Change pg_test_timing to measure in nanoseconds not microseconds.

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