Skip site navigation (1)Skip section navigation (2)
Date:      Fri, 11 Jun 2010 14:03:08 +0800
From:      Jansen Gotis <jtgotis@gmail.com>
To:        freebsd-stable@freebsd.org
Subject:   Re: "calcru: runtime went backwards" messages
Message-ID:  <AANLkTinHSQsHZF1JdVrndP4NsDNWCBwoE_kwpm_DlUYh@mail.gmail.com>
In-Reply-To: <20100610230300.GA51804@stack.nl>
References:  <AANLkTimpKW8-MyWKKo7cylqyb3sND8BGX-woMd2P5YE5@mail.gmail.com> <20100610230300.GA51804@stack.nl>

next in thread | previous in thread | raw e-mail | index | archive | help
On Fri, Jun 11, 2010 at 7:03 AM, Jilles Tjoelker <jilles@stack.nl> wrote:
> On Fri, Jun 11, 2010 at 12:35:05AM +0800, Jansen Gotis wrote:
>> Hi, for the past couple of months since moving to RELENG_8 I've been
>> receiving "calcru: runtime went backwards" messages on the console.
>
<snip>
>
> This may well be a manifestation of a brokenness (which should not be
> unknown) in how FreeBSD stores CPU time utilization. The time is
> maintained in "CPU ticks" (CPU clock cycles), so if the clock frequency
> changes, the values of existing processes will be wrong (a jump when
> converted to seconds). When calcru detects this, it generates messages
> like the above. If this analysis is right, the messages can be ignored,
> but indicate that CPU time statistics may be inaccurate.
>

You're probably right, the messages can be ignored. I don't see any issues
other than the messages being printed on the console; I don't experience
freezing, etc. It just struck me as weird because searching the -current and
-stable mailing lists does not show anyone else having the issue as recently
as I have.

Just some more info to add which I forgot about last time...setting kern.hz to
100 did not help.

Thanks for the reply.


Best regards,
Jansen



Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?AANLkTinHSQsHZF1JdVrndP4NsDNWCBwoE_kwpm_DlUYh>