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Date:      Tue, 6 Sep 2011 18:49:01 -0600
From:      Manish Vachharajani <manishv@lineratesystems.com>
To:        Eitan Adler <lists@eitanadler.com>
Cc:        Alexander Best <arundel@freebsd.org>, freebsd-hackers@freebsd.org
Subject:   Re: excessive use of gettimeofday(2) and other syscalls
Message-ID:  <CAHRgBhT%2BKi%2BYPiK%2Bhn=fJ91eA=31tOaTPe_5xLSHQawa=%2BFD0Q@mail.gmail.com>
In-Reply-To: <CAF6rxg=kzHP4zr_=LGnJDUQu-xEwgpy6QN=Lk4jqXa6hs=epKg@mail.gmail.com>
References:  <20110906220115.GA25048@freebsd.org> <CAHRgBhRe8n%2BV3nSzRn4_fctHB1nie2ACk7oRVOPJqqKaMUgKrg@mail.gmail.com> <CAF6rxg=kzHP4zr_=LGnJDUQu-xEwgpy6QN=Lk4jqXa6hs=epKg@mail.gmail.com>

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I believe that Linux uses a less precise clock that scales better
across cores and is much faster than the precise clock FreeBSD uses
even on one core.  I don't know POSIX and other standards well enough
to know if this is an acceptable solution on FreeBSD.  However, there
are less precise clocks on FreeBSD that are considerably faster (i.e.,
the _FAST variants).  Someone with more expertise in these matters
needs to comment on whether a change to using a _FAST clock is
appropriate in libc.  If it is acceptable, I think that it is easier
to just make time use the FAST clock instead of getting programmers to
change their programs.

On Tue, Sep 6, 2011 at 6:41 PM, Eitan Adler <lists@eitanadler.com> wrote:
> On Tue, Sep 6, 2011 at 6:44 PM, Manish Vachharajani
> <manishv@lineratesystems.com> wrote:
>> Lots of libraries assume that time is fast because it
>> is fast under Linux.
>
> Silly question, but why can't we make it fast too?
>
> --
> Eitan Adler
>

Manish



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