Date: Fri, 18 Oct 2002 10:27:04 -0700 (PDT) From: Kelly Yancey <kbyanc@posi.net> To: Petri Helenius <pete@he.iki.fi> Cc: Luigi Rizzo <rizzo@icir.org>, Lars Eggert <larse@ISI.EDU>, <freebsd-net@FreeBSD.org> Subject: Re: ENOBUFS Message-ID: <20021018102515.V1611-100000@gateway.posi.net> In-Reply-To: <0d0b01c27680$b553ba90$8c2a40c1@PHE>
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On Fri, 18 Oct 2002, Petri Helenius wrote:
> >
> > just reading the source code, yes, it appears that the card has
> > support for delayed rx/tx interrupts -- see RIDV and TIDV definitions
> > and usage in sys/dev/em/* . I don't know in what units are the values
> > (28 and 128, respectively), but it does appear that tx interrupts are
> > delayed a bit more than rx interrupts.
> >
> The thing what is looking suspect is also the "small packet interrupt" fe=
ature
> which does not seem to get modified in the em driver but is on the define=
s.
>
> If that would be on by default, we=B4d probably see interrupts "too often=
"
> because it tries to optimize interrupts for good throughput on small numb=
er
> of TCP streams.
>
Hmm. Might that explain the abysmal performance of the em driver with
packets smaller than 333 bytes?
Kelly
--
Kelly Yancey -- kbyanc@{posi.net,FreeBSD.org}
FreeBSD, The Power To Serve: http://www.freebsd.org/
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