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

From: Laurenz Albe <laurenz(dot)albe(at)cybertec(dot)at>
To: Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>, Hannu Krosing <hannuk(at)google(dot)com>
Cc: pgsql-hackers(at)lists(dot)postgresql(dot)org
Subject: Re: What is a typical precision of gettimeofday()?
Date: 2025-07-09 06:42:46
Message-ID: e781bd012e3f8d61849c35fc4ac8ea4dc39f254b.camel@cybertec.at
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On Tue, 2025-07-08 at 18:17 -0400, Tom Lane wrote:
> One other thing that bothers me as I look at the output is
>
> Per loop time including overhead: 731.26 ns
>
> That's stated in a way that makes it sound like that is a
> very solid number, when in fact it's just the average.
> We see from these test cases that there are frequently
> a few outliers that are far from the average. I'm tempted
> to rephrase as
>
> Average loop time including overhead: 731.26 ns
>
> or some variant of that. Thoughts?

I think that is a good idea.

Yours,
Laurenz Albe

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