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Date:      Sat, 29 Jul 2000 11:11:25 -0700
From:      "Justin C. Walker" <justin@apple.com>
To:        freebsd-net@freebsd.org
Subject:   Re: sub-optimal tcp_ouput() performance in the face of ENOBUFS
Message-ID:  <200007291810.LAA14583@scv2.apple.com>

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On Saturday, July 29, 2000, at 10:56 AM, Mike Silbersack wrote:

>
> On Sat, 29 Jul 2000, Justin C. Walker wrote:
>
> > On Friday, July 28, 2000, at 07:58 PM, Mike Silbersack wrote:
> > > Hm, I was going to wager that some calling procedure was acting
> > > differently depending on the return value of tcp_output, but since =
=20
ENOBUFS
> > > returns 0, and the error isn't checked anyway.
> >
> > Forgive my early-morning density, but I've read this sentence =
several  =20
> > times, and it just doesn't look right.  Could you try again?  I know =
 =20
> > there's value in it, but it isn't making it through.
> >
> > Regards,
> >
> > Justin
>
> In the case of ip_output returning ENOBUFS to tcp_output, tcp_output
> returns 0, even though there's an error.  (I guess if the ENOBUFS case =
was=20
> handled properly, 0 would be correct.  But for now, it's certainly an
> error.)
>
> But tcp_output returning an error wouldn't matter anyway, since =
nothing
> which calls tcp_output actually checks the return value.

Thanks for the clarification.

FWIW in our source (FB3.2-based), while a lot of calls are cast as =
(void), =20
the returned error actually is checked in a number of places =20
(tcp_usrreq.c).  These eventually wander back into user space, I think.

Regards,

Justin

Justin C. Walker, Curmudgeon-At-Large *
Institute for General Semantics =A0=A0               |
Manager, CoreOS Networking =A0=A0                | =A0=A0Men are from =
Earth.
Apple Computer, Inc.                               =A0=A0=A0 =A0| =
=A0=A0Women are from Earth.
2 Infinite Loop=A0=A0=A0=A0=A0=A0                                        =
  | =20
=A0=A0=A0=A0=A0=A0Deal with it.
Cupertino, CA 95014=A0=A0=A0=A0                               |
=
*------------------------------------------------------*------------------=
------------------*


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