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To: Adrian Chadd <adrian@freebsd.org>
Subject: Re: Change default VFS timestamp precision?
In-reply-to: <CAJ-Vmokkc-p4-keMExxT+wyjugA8zYRS2XRv6VucWnfH0iw_Pw@mail.gmail.com>
From: "Poul-Henning Kamp" <phk@phk.freebsd.dk>
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Date: Wed, 17 Dec 2014 19:09:14 +0000
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Cc: "freebsd-arch@freebsd.org" <arch@freebsd.org>,
 Jilles Tjoelker <jilles@stack.nl>
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--------
In message <CAJ-Vmokkc-p4-keMExxT+wyjugA8zYRS2XRv6VucWnfH0iw_Pw@mail.gmail=
.com>
, Adrian Chadd writes:

>> I think it is over 10 years ago when make(1) first started seeing
>> identical timestamps which wasn't.
>>
>> In most Makefiles this doesn't matter, but there are cases, in particul=
ar
>> in less integrated families of makefiles than our own.
>
>Surely there has to be better ways of doing this stuff. Computers keep
>getting faster; it wouldn't be out of the realm of possibility that we
>could see a compiler read, compile and spit out a .o inside of a
>millisecond. (Obviously not C++, but..)

A millisecond is pushing it, all things considered, it would have to
be an utterly trivial source file for a utterly trivial language.

Given that it has epsilon cost, switching to TSP_HZ should be a
no-brainer, I've been running that for ages.

Why TSP_USEC exists is beyond me, it's slower and worse than TSP_NSEC.

But going to TSP_NSEC by default seems unwarranted to me.

-- =

Poul-Henning Kamp       | UNIX since Zilog Zeus 3.20
phk@FreeBSD.ORG         | TCP/IP since RFC 956
FreeBSD committer       | BSD since 4.3-tahoe    =

Never attribute to malice what can adequately be explained by incompetence=
.