Skip site navigation (1)Skip section navigation (2)
Date:      Sun, 1 Dec 2013 23:14:36 -0800
From:      John-Mark Gurney <jmg@funkthat.com>
To:        Venkata Duvvuru <VenkatKumar.Duvvuru@Emulex.Com>
Cc:        Matthew Fleming <mdf@freebsd.org>, "freebsd-current@freebsd.org" <freebsd-current@freebsd.org>
Subject:   Re: sysctl add macros
Message-ID:  <20131202071436.GI55638@funkthat.com>
In-Reply-To: <BF3270C86E8B1349A26C34E4EC1C44CB2C7E46D7@CMEXMB1.ad.emulex.com>
References:  <BF3270C86E8B1349A26C34E4EC1C44CB2C7E0C74@CMEXMB1.ad.emulex.com> <CAMBSHm9K_Yu9SDdHP1exh99RXq9tta7kwVWQbEY_zs2ZJa5RjQ@mail.gmail.com> <BF3270C86E8B1349A26C34E4EC1C44CB2C7E0D3E@CMEXMB1.ad.emulex.com> <20131130213006.GC55638@funkthat.com> <BF3270C86E8B1349A26C34E4EC1C44CB2C7E46D7@CMEXMB1.ad.emulex.com>

next in thread | previous in thread | raw e-mail | index | archive | help
Venkata Duvvuru wrote this message on Mon, Dec 02, 2013 at 07:10 +0000:
> I could use an int variable but if I have to dump huge number of statistics through sysctl in which case I need to add many such variables to the nodes and even if most of these variables are char I have to declare them as int, hence resulting in an increased footprint.

If it's a few 10s of vars, then it isn't a big deal, but if it is 1000's,
then you might want to look at another method to extract the data since
the overhead of sysctl is expensive...  Something like writing a _PROC
routine that will copy them all out in a single sysctl call..

> -----Original Message-----
> From: John-Mark Gurney [mailto:jmg@funkthat.com] 
> Sent: Sunday, December 01, 2013 3:00 AM
> To: Venkata Duvvuru
> Cc: Matthew Fleming; freebsd-current@freebsd.org
> Subject: Re: sysctl add macros
> 
> Venkata Duvvuru wrote this message on Mon, Nov 25, 2013 at 14:58 +0000:
> > The problem with using int or u_int for 1 or 2 byte values is that while printing these 1 or 2 byte values I observed that sysctl module is considering 4 bytes. Hence I see an undesired output. It is actually considering the next two bytes also as the value.
> 
> If you _NEED_ to use a char or short, you need to write your own/clone it from the macros...
> 
> Why can't you use an int for this variable?
> 
> > From: mdf356@gmail.com [mailto:mdf356@gmail.com] On Behalf Of Matthew 
> > Fleming
> > Sent: Monday, November 25, 2013 8:18 PM
> > To: Venkata Duvvuru
> > Cc: freebsd-current@freebsd.org
> > Subject: Re: sysctl add macros
> > 
> > On Mon, Nov 25, 2013 at 3:35 AM, Venkata Duvvuru <VenkatKumar.Duvvuru@emulex.com<mailto:VenkatKumar.Duvvuru@emulex.com>> wrote:
> > Hi,
> > I'm unable to figure out how to add an unsigned short or an unsigned char values to a sysctl node.
> > SYSCTL_ADD_INT, SYSCTL_ADD_UINT, etc., are present but to add a char or a short values I couldn't find any macros.
> > 
> > Could you please let me know how to add them?
> > 
> > FreeBSD does not have any sysctl handlers for 1 or 2 byte values.  FreeBSD code that wants to do this has used int or u_int instead of a smaller type.
> 
> -- 
>   John-Mark Gurney				Voice: +1 415 225 5579
> 
>      "All that I will do, has been done, All that I have, has not."
> _______________________________________________
> freebsd-current@freebsd.org mailing list
> http://lists.freebsd.org/mailman/listinfo/freebsd-current
> To unsubscribe, send any mail to "freebsd-current-unsubscribe@freebsd.org"

-- 
  John-Mark Gurney				Voice: +1 415 225 5579

     "All that I will do, has been done, All that I have, has not."



Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?20131202071436.GI55638>